Very short note today! Yay!
Ex-Tropical Depression Nicole:
She's fully merged with that front that stretches up the eastern side of the US. It's dumped a lot of rain all over the place, as expected. The NHC went back and changed their assessment on Nicole for the 12 hours (possibly longer) before they initially called her a Tropical Storm, so in the final records she will officially be a Tropical Storm for longer than 6 hours. It'll all be looked at much more carefully after the season is over but there is clearly some ambiguity about this system in the 'real-time' analysis. Personally, I don't think she was a Tropical Storm. Oh well. With all this rain, it'll all come out in the wash. ;-) This is my last entry on this system.
Atlantic Blob:
Blob (10% chance of forming) + Blobette (20% chance of forming) = Blob (30% chance of forming). Nice (thanks to Karen M. for the maths idea). The two systems from yesterday got together to make a cute Blob. (Awww). And to make life easier for the rest of us. Vorticity in the lowest half of the troposphere has improved, but it covers a large area around 15 N, from 45-50W. However, the convection is not really very cohesive. It is a perfect Blob! We'll see if this develops further. It's currently heading WNW at 15-20mph. It is already bringing wet weather to some of the Caribbean Islands. The next name is Otto, but no more on this unless it develops.
It's raining here in the UK too. Again. ;-)
Toodle pippy!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Thursday, September 30, 2010
Wednesday, September 29, 2010
Tropical Storm Nicole, and a couple of Atlantic Blobs: September 29, Update A
Ever get the feeling it's just about the numbers? Sigh.
Not-Tropical Storm Nicole:
<open Sarcasm> This was the most amazing Tropical Storm I've ever come across. It developed whilst crossing the mountainous regions of Cuba, an area that has knocked larger storms (actual, real, genuine, honest-to-goodness hurricanes) to their feet. It was also remarkably asymmetric for a Tropical Storm, with the center of circulation quite clearly off to one side of the really strong convection. It was fabulous how the vorticity and low pressure extended from the northern Caribbean across Cuba to Florida - a rather large area. The same area of vorticity that is connected at some levels of the atmosphere to the low front that extends up the eastern US seaboard. And finally, it's the only Tropical Storm I can think of that formed over land, but dissipated as soon as it got to water.... Yes indeed, quite an amazing 'Tropical Storm'. <close Sarcasm>
But hey, we have another named storm to add to the number, right? (oops, sorry, that was residual sarcasm. Don't know how that escaped from the bit above!)
The NHC upgraded our Tropical Depression to Tropical Storm Nicole in their 11am advisory... and 6 hours later, in their 5pm advisory they wrote "NICOLE DISSIPATES OVER THE STRAITS OF FLORIDA". Remarkable. I'm actually just astounded. They said the upgrade was based on land, buoy and ship observations. So, being the grouchy old person that I am and being *slightly* suspicious that it 'formed' over land with 'hills', I went and had a look at ALL the buoy and coastal station observations I could find - both south of Cuba and to the north along the Keys and up towards Miami. I also looked at the satellite winds. I'd like to know exactly what data they were looking at that showed sustained winds of 39mph please (I think they should post links to show those of us who might be a tad er... skeptical, shall we say?). The most I found were around 32mph. Sigh. And they were doing so well yesterday!
The basis for her dissipating was "AIRCRAFT AND SURFACE OBSERVATIONS INDICATE THAT THE CIRCULATION OF NICOLE HAS DEGENERATED INTO AN ELONGATED AREA OF LOW PRESSURE." (from the NHC 5pm advisory). She's ALWAYS had an elongated area of low pressure!! None of this 'degeneration' went on as far as I can see! And so, with the official word being that she has dissipated, the NHC have said they are done issuing advisories on this storm (THE CENTER... WHICH WAS NEVER VERY WELL DEFINED...HAS BECOME UN-TRACKABLE AND THIS WILL BE THE LAST NHC ADVISORY ON THIS SYSTEM.)
<breathe><breathe><think of happy place> Ok... better now. ;-)
Anyway, she's now officially "dissipated" over the warm waters of the Straits of Florida. Her 'center' was last seen at 24.5N, 80W, and her central pressure was 996mb. Winds are officially 40mph still, which in some people's books would make her a weak TS (Range 39-73mph), but she's not a Tropical Storm beastie and never has been! She's a different sort of system as I mentioned yesterday (and as the NHC recognized yesterday too!) - so although she's 'dissipated' she can still be a bit breezy. She's moving NNE at 12mph and she'll merge with that front as expected. She's still got a heck of a lot of convection - poor Jamaica really got hammered with strong thunderstorms today (as well as yesterday). Basically, the southeast US, Bahamas, Cuba, PR, maybe the VIs etc... will get some stormy rainy windy sort of weather, but its not a Tropical Storm.
I can't seem to access the satellite data - server must be down. So I might write about this again tomorrow instead of closing this one down now.
Atlantic Blob and Blobette:
There are a couple of blobby things to look out for. One is somewhere in the 15N, 55W region, heading NW (towards the northern Leeward Isles). It has more convection than vorticity at the moment, but the vorticity has been picking up in the lowest part of the troposphere. The second one is east of this, somewhere around 10N, 30W and is moving WNW. This, too, has convection, but it also has more vorticity in the lower half of the troposphere so I think this has a higher chance of developing (if I were to choose between the two). Best to keep an eye on them both! Umm... keep two eyes on them both. One on each. Yeah. That's the plan. ;-)
What an odd day. I still can't believe they named Nicole. I was *so* impressed because they totally had the right call yesterday (in my book). I wish I knew what they were looking at when they made that call today! <resigned shaking of head>.
More tomorrow - if only to say that I'm not going to say anything about the former Nicole!
Toodle pip!
J.
p.s.: I finally joined Twitter today and am officially a 'twit', which some of you probably suspected all along. ;-) I'll be tweeting when I post a new blog entry. (That sentence barely makes sense to me). I don't know if I'll tweet about much else because, as you know, although I am a person of few words I'm not sure how anyone can say anything in 140 characters or less! Signing off now, 'JyovianStorm'. ;-)
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Not-Tropical Storm Nicole:
<open Sarcasm> This was the most amazing Tropical Storm I've ever come across. It developed whilst crossing the mountainous regions of Cuba, an area that has knocked larger storms (actual, real, genuine, honest-to-goodness hurricanes) to their feet. It was also remarkably asymmetric for a Tropical Storm, with the center of circulation quite clearly off to one side of the really strong convection. It was fabulous how the vorticity and low pressure extended from the northern Caribbean across Cuba to Florida - a rather large area. The same area of vorticity that is connected at some levels of the atmosphere to the low front that extends up the eastern US seaboard. And finally, it's the only Tropical Storm I can think of that formed over land, but dissipated as soon as it got to water.... Yes indeed, quite an amazing 'Tropical Storm'. <close Sarcasm>
But hey, we have another named storm to add to the number, right? (oops, sorry, that was residual sarcasm. Don't know how that escaped from the bit above!)
The NHC upgraded our Tropical Depression to Tropical Storm Nicole in their 11am advisory... and 6 hours later, in their 5pm advisory they wrote "NICOLE DISSIPATES OVER THE STRAITS OF FLORIDA". Remarkable. I'm actually just astounded. They said the upgrade was based on land, buoy and ship observations. So, being the grouchy old person that I am and being *slightly* suspicious that it 'formed' over land with 'hills', I went and had a look at ALL the buoy and coastal station observations I could find - both south of Cuba and to the north along the Keys and up towards Miami. I also looked at the satellite winds. I'd like to know exactly what data they were looking at that showed sustained winds of 39mph please (I think they should post links to show those of us who might be a tad er... skeptical, shall we say?). The most I found were around 32mph. Sigh. And they were doing so well yesterday!
The basis for her dissipating was "AIRCRAFT AND SURFACE OBSERVATIONS INDICATE THAT THE CIRCULATION OF NICOLE HAS DEGENERATED INTO AN ELONGATED AREA OF LOW PRESSURE." (from the NHC 5pm advisory). She's ALWAYS had an elongated area of low pressure!! None of this 'degeneration' went on as far as I can see! And so, with the official word being that she has dissipated, the NHC have said they are done issuing advisories on this storm (THE CENTER... WHICH WAS NEVER VERY WELL DEFINED...HAS BECOME UN-TRACKABLE AND THIS WILL BE THE LAST NHC ADVISORY ON THIS SYSTEM.)
<breathe><breathe><think of happy place> Ok... better now. ;-)
Anyway, she's now officially "dissipated" over the warm waters of the Straits of Florida. Her 'center' was last seen at 24.5N, 80W, and her central pressure was 996mb. Winds are officially 40mph still, which in some people's books would make her a weak TS (Range 39-73mph), but she's not a Tropical Storm beastie and never has been! She's a different sort of system as I mentioned yesterday (and as the NHC recognized yesterday too!) - so although she's 'dissipated' she can still be a bit breezy. She's moving NNE at 12mph and she'll merge with that front as expected. She's still got a heck of a lot of convection - poor Jamaica really got hammered with strong thunderstorms today (as well as yesterday). Basically, the southeast US, Bahamas, Cuba, PR, maybe the VIs etc... will get some stormy rainy windy sort of weather, but its not a Tropical Storm.
I can't seem to access the satellite data - server must be down. So I might write about this again tomorrow instead of closing this one down now.
Atlantic Blob and Blobette:
There are a couple of blobby things to look out for. One is somewhere in the 15N, 55W region, heading NW (towards the northern Leeward Isles). It has more convection than vorticity at the moment, but the vorticity has been picking up in the lowest part of the troposphere. The second one is east of this, somewhere around 10N, 30W and is moving WNW. This, too, has convection, but it also has more vorticity in the lower half of the troposphere so I think this has a higher chance of developing (if I were to choose between the two). Best to keep an eye on them both! Umm... keep two eyes on them both. One on each. Yeah. That's the plan. ;-)
What an odd day. I still can't believe they named Nicole. I was *so* impressed because they totally had the right call yesterday (in my book). I wish I knew what they were looking at when they made that call today! <resigned shaking of head>.
More tomorrow - if only to say that I'm not going to say anything about the former Nicole!
Toodle pip!
J.
p.s.: I finally joined Twitter today and am officially a 'twit', which some of you probably suspected all along. ;-) I'll be tweeting when I post a new blog entry. (That sentence barely makes sense to me). I don't know if I'll tweet about much else because, as you know, although I am a person of few words I'm not sure how anyone can say anything in 140 characters or less! Signing off now, 'JyovianStorm'. ;-)
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Tuesday, September 28, 2010
Tropical Depression 16: September 28, Update A
Well I must say that was lovely ... a whole day off! Gosh. What a luxury!! ;-)
So we have one pesky little blobette out there in the Caribbean, huh? It may be the future Nicole, but I'm not very convinced of that. The NHC upgraded it to a Tropical Depression earlier today, and for once I must say I approve of this and their reasoning! It's a good spot to put it in becuse this is a funny little thing - not quite a Tropical or Subtropical Storm in structure, but not quite a front either. And it formed in a topsy turvy sort of manner. The word on the street (amongst the hurricane hommies - ooh... band name? ;-)) is that this is something that is more frequently seen in the Western Pacific, and is a monsoon-sort of system which may or may not develop into a tropical storm. It's not often we see this in the Atlantic. But this has been a topsy turvy sort of tropical storm year across the planet, with more storms in the Atlantic than in the Pacific. Usually the Atlantic is the slow one! I don't really watch the other basins as intently as I do the Atlantic (because I don't have enough hours in the day) so I'm afraid that for now it's a bit out of my realm to talk about monsoonal systems and whatnots in the Western Pacific. I'll see what I can dig up for some future quiz!
This Tropical Depression is still a blobette at heart and has more ferocious looking convection (rain, thunderstorms etc) than wind speed. It is officially centered at 21.4N, 82.0W, but it covers such a broad area of circulation that it's a bit tricky getting a good handle on that 'center'. It is moving NNE at 8mph. A minimum central pressure of 997mb was observed by Hurricane Hunter planes (again this was over a broad area) and the maximum winds are 35mph. BUT, because this isn't a Tropical Storm, the strongest winds are actually about 200 nautical miles southeast of the center. Southeast is also where the heaviest convection happens to be - the strongest thunderstorms, heaviest rains.
This TD is looking a bit lopsided - the official center of circulation is to one side of the heavy convection. The track takes it over Cuba and on to Southeast Florida - this is along a low pressure front that has also been responsible for dumping rain over the Carolinas. There will be rain over the next few days - the Caribbean islands are already getting drenched. I haven't seen the little Cayman Islands all day, and Jamaica is really getting some severe thunderstorms at the moment! In the US, get your wellies and brollies ready... and possibly your canoes too! ;-) Parts (all?) of the southeastern seaboard have already had some rain from the front that is attached to this, but there will probably be quite a few bucket-fulls to come. The forecast has it as a Tropical Storm within a few hours, as it gets to Cuba, and then all the way up to North Carolina. I don't see it becoming a Tropical Storm as it crosses Cuba (the convection will decrease as it crosses that land), but there is a possibility that it will become a bit better organized as it moves over the Florida Current and Gulf Stream, after leaving Florida. Of course by then it might be completely part of that low pressure front and not a Tropical Storm at all! I also think it might be going a little east of the center of cone track, but it doesn't really matter because, if anything, this is mostly going to be a rain event for people in the US.
Until tomorrow,
A bientot!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
So we have one pesky little blobette out there in the Caribbean, huh? It may be the future Nicole, but I'm not very convinced of that. The NHC upgraded it to a Tropical Depression earlier today, and for once I must say I approve of this and their reasoning! It's a good spot to put it in becuse this is a funny little thing - not quite a Tropical or Subtropical Storm in structure, but not quite a front either. And it formed in a topsy turvy sort of manner. The word on the street (amongst the hurricane hommies - ooh... band name? ;-)) is that this is something that is more frequently seen in the Western Pacific, and is a monsoon-sort of system which may or may not develop into a tropical storm. It's not often we see this in the Atlantic. But this has been a topsy turvy sort of tropical storm year across the planet, with more storms in the Atlantic than in the Pacific. Usually the Atlantic is the slow one! I don't really watch the other basins as intently as I do the Atlantic (because I don't have enough hours in the day) so I'm afraid that for now it's a bit out of my realm to talk about monsoonal systems and whatnots in the Western Pacific. I'll see what I can dig up for some future quiz!
This Tropical Depression is still a blobette at heart and has more ferocious looking convection (rain, thunderstorms etc) than wind speed. It is officially centered at 21.4N, 82.0W, but it covers such a broad area of circulation that it's a bit tricky getting a good handle on that 'center'. It is moving NNE at 8mph. A minimum central pressure of 997mb was observed by Hurricane Hunter planes (again this was over a broad area) and the maximum winds are 35mph. BUT, because this isn't a Tropical Storm, the strongest winds are actually about 200 nautical miles southeast of the center. Southeast is also where the heaviest convection happens to be - the strongest thunderstorms, heaviest rains.
This TD is looking a bit lopsided - the official center of circulation is to one side of the heavy convection. The track takes it over Cuba and on to Southeast Florida - this is along a low pressure front that has also been responsible for dumping rain over the Carolinas. There will be rain over the next few days - the Caribbean islands are already getting drenched. I haven't seen the little Cayman Islands all day, and Jamaica is really getting some severe thunderstorms at the moment! In the US, get your wellies and brollies ready... and possibly your canoes too! ;-) Parts (all?) of the southeastern seaboard have already had some rain from the front that is attached to this, but there will probably be quite a few bucket-fulls to come. The forecast has it as a Tropical Storm within a few hours, as it gets to Cuba, and then all the way up to North Carolina. I don't see it becoming a Tropical Storm as it crosses Cuba (the convection will decrease as it crosses that land), but there is a possibility that it will become a bit better organized as it moves over the Florida Current and Gulf Stream, after leaving Florida. Of course by then it might be completely part of that low pressure front and not a Tropical Storm at all! I also think it might be going a little east of the center of cone track, but it doesn't really matter because, if anything, this is mostly going to be a rain event for people in the US.
Until tomorrow,
A bientot!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Sunday, September 26, 2010
Remnant Lows Lisa and Matthew and a Caribbean Blobette: September 25, Update A
And the lazy weekend theme continues for me (who hiked 21 miles over some hilly coastal terrain this weekend and can no longer move her legs. And people run marathons??? how? why? how?!?) and our storms. (yay!)
Both Lisa and Matthew are now officially remnant lows. I agree with this assesment.
Tropical Depression Lisa:
Lisa is at 26.1N, 29.4W, moving NNW at 7pm. Winds are estimated to be 30mph and her central pressure is 1008mb. Although vorticity (circulation) is strong in the lowest half of the troposphere, the convection has pretty much dropped away. This is my last update on this system.
Tropical Depression Matthew:
Matthew is at 17.4N, 92.9W, moving W at 9mph. As I thought, he is now moving westward rather than northwest, so his track has changed slightly and instead of dissipating over the Yucatan Peninsula, he'll go bid farewell over central Mexico. Winds are 25mph and central pressure is 1003mb. Finally! After a couple of days over land the vorticity and convection are beginning to decrease. Woo-hoo! There is still a lot of rain in the system but the thunderstorm level activity has diminished. This is my last update on this system.
Caribbean Blobette:
There is an area in the Caribbean that the NHC have marked as having 10% chance of becoming a storm in the next 48 hours. This is an area that was highlighted by those experimental long-term (7-10 days) forecast models that I mentioned in a much earlier blog (well it seemed like a long time ago). Although there is a bit of convection (as a result of Matthew I think), there is not much vorticity so we'll see if this develops. The NHC mentioned this as a possiblity at least twice (that I saw) during their Matthew write-ups. The models envision this blobette becoming a thing to chat about on Weds or Thurs. Something to look forward to, hey? ;-)
That is all for this rather lovely weekend! :-)
Toodle pip!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Both Lisa and Matthew are now officially remnant lows. I agree with this assesment.
Tropical Depression Lisa:
Lisa is at 26.1N, 29.4W, moving NNW at 7pm. Winds are estimated to be 30mph and her central pressure is 1008mb. Although vorticity (circulation) is strong in the lowest half of the troposphere, the convection has pretty much dropped away. This is my last update on this system.
Tropical Depression Matthew:
Matthew is at 17.4N, 92.9W, moving W at 9mph. As I thought, he is now moving westward rather than northwest, so his track has changed slightly and instead of dissipating over the Yucatan Peninsula, he'll go bid farewell over central Mexico. Winds are 25mph and central pressure is 1003mb. Finally! After a couple of days over land the vorticity and convection are beginning to decrease. Woo-hoo! There is still a lot of rain in the system but the thunderstorm level activity has diminished. This is my last update on this system.
Caribbean Blobette:
There is an area in the Caribbean that the NHC have marked as having 10% chance of becoming a storm in the next 48 hours. This is an area that was highlighted by those experimental long-term (7-10 days) forecast models that I mentioned in a much earlier blog (well it seemed like a long time ago). Although there is a bit of convection (as a result of Matthew I think), there is not much vorticity so we'll see if this develops. The NHC mentioned this as a possiblity at least twice (that I saw) during their Matthew write-ups. The models envision this blobette becoming a thing to chat about on Weds or Thurs. Something to look forward to, hey? ;-)
That is all for this rather lovely weekend! :-)
Toodle pip!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Saturday, September 25, 2010
Tropical Storm Lisa and Tropical Depression Matthew: September 25, Update A
It's saturday today and nothing much is going on ... so I'm going to do a weekend thing and be lazy. ;-)
Tropical Storm Lisa:
She's currently at 23.7N, 28.4W and moving N at 12mph. She's too disorganized for me to see her center, so I'll go with the official word. Her winds are now 50mph (far more reasonable, in my humbly opinionated point of view ;-) ) and central pressure is 996 mb, making her a mid-sized Tropical Storm (range: 39-73mph). There is wind shear, not much convection (there are clouds, but not too much rain and thunder) and vorticity is strong only in the lower half of the troposphere - mid-size TS sounds about right. She's just bothering the fish and anyone who happens to be in that part of the Atlantic. I agree with the NHC assessment on her today, so this is all I have to say.
Tropical Depression Matthew:
He is currently at 17.4N, 89.4W and moving NW at 14mph. Winds are (apparently, huh) 35mph and minimum pressure is 1003mb. The forecast calls for him to slow down and become stationary over the Yucatan peninsula soon, and because he'll be over land he will weaken further and dissipate. As expected, the dissipation is slower than was forecast yesterday and has been pushed back from Monday to Tuesday afternoon. You all know my take on the reason for that - because his intensity was (and continues) to be underestimated. I would put him as a Tropical Storm now, given that he has strong vorticity in the troposphere (including a small amount in the upper troposphere) and he is still producing torrential rain and thunderstorms, despite being in an area of wind shear and over land. Also, he's a bit messy and disorganized (he could do with a proper filing system! ;-)) but he looks a little southwest of that location, in which case I can see him maybe continuing to move westward(ish) for longer than forecast instead of becoming stationary. I'll be looking out for the forecasted slowing down tomorrow afternoon.
And that's it for my lazy Saturday. Enjoy the weekend! :-)
Ciao for now!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Tropical Storm Lisa:
She's currently at 23.7N, 28.4W and moving N at 12mph. She's too disorganized for me to see her center, so I'll go with the official word. Her winds are now 50mph (far more reasonable, in my humbly opinionated point of view ;-) ) and central pressure is 996 mb, making her a mid-sized Tropical Storm (range: 39-73mph). There is wind shear, not much convection (there are clouds, but not too much rain and thunder) and vorticity is strong only in the lower half of the troposphere - mid-size TS sounds about right. She's just bothering the fish and anyone who happens to be in that part of the Atlantic. I agree with the NHC assessment on her today, so this is all I have to say.
Tropical Depression Matthew:
He is currently at 17.4N, 89.4W and moving NW at 14mph. Winds are (apparently, huh) 35mph and minimum pressure is 1003mb. The forecast calls for him to slow down and become stationary over the Yucatan peninsula soon, and because he'll be over land he will weaken further and dissipate. As expected, the dissipation is slower than was forecast yesterday and has been pushed back from Monday to Tuesday afternoon. You all know my take on the reason for that - because his intensity was (and continues) to be underestimated. I would put him as a Tropical Storm now, given that he has strong vorticity in the troposphere (including a small amount in the upper troposphere) and he is still producing torrential rain and thunderstorms, despite being in an area of wind shear and over land. Also, he's a bit messy and disorganized (he could do with a proper filing system! ;-)) but he looks a little southwest of that location, in which case I can see him maybe continuing to move westward(ish) for longer than forecast instead of becoming stationary. I'll be looking out for the forecasted slowing down tomorrow afternoon.
And that's it for my lazy Saturday. Enjoy the weekend! :-)
Ciao for now!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Friday, September 24, 2010
Hurricane Lisa and Tropical Storm Matthew: September 24, Update A
I'm attaching (and on blog site) the latest Infrared satellite image of the Atlantic, taken by the GOES-East satellite. There are two blobs. One is over Central America (Nicaragua/Honduras) and has moisture and clouds associated with it that stretch across a large region of the Caribbean. The other is way over in the eastern Atlantic, at around 20N, 27W. Can you identify which storm is officially the weaker of the two (and is a weak Tropical Storm) and which is the one that has just strengthened to a Hurricane? Remember an Infrared image shows cloud top temperatures. The coldest cloud tops are marked by the red going into dark grey colours and one can expect pretty strong thunderstorms, torrential rain, and possible tornadoes in those areas, the orange areas are thunderstorms with heavy rain, the yellows (as cloud tops get warmer) indicate areas of rain, and the blues going into whites (warmest cloud tops) are just cloudy areas. (Answers in the rest of this entry - and er, in the subject header ;-)).
Hurricane Lisa:
She has some clouds, but not a lot of strong convection or rainfall. She also has vorticity (circulation) in the lowest half of the troposphere, but nothing at higher altitudes. Her center is officially at 20.0N, 27.8W and she's finally decided she's tired of hanging out in the same place so she's heading north at 8mph. Her central pressure is estimated to be 989mb and her wind speed is estimated to be 75mph, making her a cat 1 hurricane (range: 73-95mph). Hurricane force winds extend out a whopping 10 miles from the center. I agree, there is a little itsy bitsy eye trying to form, but yes, of course I disagree! ;-) Well... I agree with the name. The location is fractionally off - I think she's slightly to the east of that - and she's heading NNE. But the estimated winds I am really not sure about. I think she's weaker than that. I looked at the satellite wind field (also attached/on blog site) from a couple of hours ago. It's easy to see the circular pattern in winds that is Lisa. Even generously it seems to me that the wind speeds are about 40-45mph (35-40 knots; 1 knot = 1.15 mph), but if the hurricane force winds are only 10 miles from the center (which they are estimating from satellites as well) then we might not be able to detect it from this image.
Tropical Storm Matthew:
I am really not sure about their assessment on this 'little' guy. He was our Tropical Depression 15 from yesterday and I still think that, like Karl, they underestimated his intensity. The vorticity is *really* strong (a lot stronger than Lisa's) in the lowest half of the troposphere and he has vorticity in the upper levels of the troposphere which indicates a strong Tropical Storm, possibly close to a weak hurricane. He has a LOT of convection! Very strong thunderstorms, torrential rain, possible tornadoes. He's made landfall in Nicaragua, but this very strong convection is across Honduras too. It looks like his center at the moment is at 15N, 83.7W - at the Nicaragua/Honduras border. Officially he is moving West at 15mph - I think it's more WNW. His estimated central pressure is 998mb and winds are 45 mph, making him a weak (!?!) Tropical Storm (range: 39-73mph). A plane went into the system when he was still over water, about 7 or so hours ago and found winds of 45 knots... hmm... 45 x 1.15 = 51.75 mph winds. Not 45mph winds. He has made landfall since then, so I can see their reasoning that he'll have weakened. Sure doesn't look like it to me at the moment. I'm sure it doesn't feel like it to the people underneath either.
Earlier today (5am advisory - over 12 hours ago), the NHC wrote: "THE CURRENT SHEAR IS FORECAST TO SUBSIDE IN 12-24 HR...SO THE MAIN
FACTOR CONTROLLING THE INTENSITY WILL BE LAND INTERACTION." I don't think the impact of the ocean is fully being taken into account in these intensities - even though it's been shown time and time again that the deeper the warm water is, the stronger the storm generally becomes (barring strong atmospheric inhibition). The most famous examples were Katrina and Rita in 2005 - they became cat 5 as they went over the Loop Current.
Now he is over land there's certainly the possibility that the convection will decrease, especially as there is also a bit of wind shear at the moment, but he has got some lusciously warm waters to sustain him for a while. I think he's going to cause a bit of a mess in Central America. I wouldn't be overly surprised if his intensity increases a bit before decreasing. As for the track, the forecast has him staying on land (mostly), crossing Nicaragua, Honduras, and Guatemala, and then dissipating over Mexico by Monday afternoon. I can see this as a viable track, but if he is a little stronger then it might take him a little longer. Speaking of dissipation, that's what seems to have happened to the forecast track making a right turn and heading northeast. I can see the low pressure front that would have steered him in that direction - it's in the northern Gulf area at the moment. In fairness to the NHC, they did say yesterday that both the track and intensity forecasts for this storm had a high level of uncertainty and could change drastically.
More tomorrow. Time for some sleepings over here. Have fun over there!
Byee!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Hurricane Lisa:
She has some clouds, but not a lot of strong convection or rainfall. She also has vorticity (circulation) in the lowest half of the troposphere, but nothing at higher altitudes. Her center is officially at 20.0N, 27.8W and she's finally decided she's tired of hanging out in the same place so she's heading north at 8mph. Her central pressure is estimated to be 989mb and her wind speed is estimated to be 75mph, making her a cat 1 hurricane (range: 73-95mph). Hurricane force winds extend out a whopping 10 miles from the center. I agree, there is a little itsy bitsy eye trying to form, but yes, of course I disagree! ;-) Well... I agree with the name. The location is fractionally off - I think she's slightly to the east of that - and she's heading NNE. But the estimated winds I am really not sure about. I think she's weaker than that. I looked at the satellite wind field (also attached/on blog site) from a couple of hours ago. It's easy to see the circular pattern in winds that is Lisa. Even generously it seems to me that the wind speeds are about 40-45mph (35-40 knots; 1 knot = 1.15 mph), but if the hurricane force winds are only 10 miles from the center (which they are estimating from satellites as well) then we might not be able to detect it from this image.
Tropical Storm Matthew:
I am really not sure about their assessment on this 'little' guy. He was our Tropical Depression 15 from yesterday and I still think that, like Karl, they underestimated his intensity. The vorticity is *really* strong (a lot stronger than Lisa's) in the lowest half of the troposphere and he has vorticity in the upper levels of the troposphere which indicates a strong Tropical Storm, possibly close to a weak hurricane. He has a LOT of convection! Very strong thunderstorms, torrential rain, possible tornadoes. He's made landfall in Nicaragua, but this very strong convection is across Honduras too. It looks like his center at the moment is at 15N, 83.7W - at the Nicaragua/Honduras border. Officially he is moving West at 15mph - I think it's more WNW. His estimated central pressure is 998mb and winds are 45 mph, making him a weak (!?!) Tropical Storm (range: 39-73mph). A plane went into the system when he was still over water, about 7 or so hours ago and found winds of 45 knots... hmm... 45 x 1.15 = 51.75 mph winds. Not 45mph winds. He has made landfall since then, so I can see their reasoning that he'll have weakened. Sure doesn't look like it to me at the moment. I'm sure it doesn't feel like it to the people underneath either.
Earlier today (5am advisory - over 12 hours ago), the NHC wrote: "THE CURRENT SHEAR IS FORECAST TO SUBSIDE IN 12-24 HR...SO THE MAIN
FACTOR CONTROLLING THE INTENSITY WILL BE LAND INTERACTION." I don't think the impact of the ocean is fully being taken into account in these intensities - even though it's been shown time and time again that the deeper the warm water is, the stronger the storm generally becomes (barring strong atmospheric inhibition). The most famous examples were Katrina and Rita in 2005 - they became cat 5 as they went over the Loop Current.
Now he is over land there's certainly the possibility that the convection will decrease, especially as there is also a bit of wind shear at the moment, but he has got some lusciously warm waters to sustain him for a while. I think he's going to cause a bit of a mess in Central America. I wouldn't be overly surprised if his intensity increases a bit before decreasing. As for the track, the forecast has him staying on land (mostly), crossing Nicaragua, Honduras, and Guatemala, and then dissipating over Mexico by Monday afternoon. I can see this as a viable track, but if he is a little stronger then it might take him a little longer. Speaking of dissipation, that's what seems to have happened to the forecast track making a right turn and heading northeast. I can see the low pressure front that would have steered him in that direction - it's in the northern Gulf area at the moment. In fairness to the NHC, they did say yesterday that both the track and intensity forecasts for this storm had a high level of uncertainty and could change drastically.
More tomorrow. Time for some sleepings over here. Have fun over there!
Byee!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Thursday, September 23, 2010
Tropical Depression Lisa & Tropical Depression 15: September 23, Update A
Gollygeewhiz! Some of these storms are like boomerangs this year! We have the remnants of Julia in the middle of the Atlantic. She's been trying to stage a come-back tour but although the circulation has improved, her convection could do with a make-over. She's around 32N, 37W and is just bugging the fishies really. And then there is Lisa...
Tropical Depression Lisa:
The ultimate boomerang storm! Lisa formed near the Cape Verde Islands, headed west/northwest for a few days lulling the residents of the Cape Verde Islands into a false sense of security and sunshine, and has now returned to drop off some rain she forgot to leave the last time she was in the area. But at least she's been downgraded to a Tropical Depression because of that low pressure front to the northeast that I mentioned yesterday. She's around 17.5N, 28.9W and moving N at hardly any speed at all (2mph). Winds are 35mph and central pressure is 1002mb. Vorticity is still really good in the lowest half of the troposphere, but the convection just isn't there right now. The NHC think she might get back to being a Tropical Storm, but she won't be very strong and will stay in the Atlantic - I see nothing to disagree with in that assessment.
Tropical Depression 15:
This is the former Caribbean Blob. It was upgraded a few hours ago and is currently centered at 13.9N, 76.2W and is moving W at 15mph. Winds are 35mph and the central pressure is 1007mb. Convection has been really strong over much of the Caribbean because of this blob. I sure hope no-one is trying to get a tan on the deck of a cruise ship in the Caribbean this week! The vorticity (circulation) has slowly improved over the lowest half of the troposphere, but there's nothing higher up (which is a good thing). Although the official direction of movement is West, I think it's moving WNW and has started to move away from the South American landmass. I also think the forecast track on the NHC page is reasonable until a point. I think that it will continue to head WNW/NW towards the Nicaragua/Honduras region, and then possibly on to Belize and Mexico. It continues to experience a bit of wind shear, which is still why the development is slow. However water temperatures are rather warm at around 28-30 deg C and the warm waters of over 26.5 deg C can be found in the upper 75-100m. As it gets closer to Central America it will be closer to the deepest warm water in the ocean and, depending on it's proximity to land and how much wind shear there is, we might see it blossom like it's brother, Karl. The forecast track gets interesting after Monday (when it is over the Yucatan) - the forecast shows it doing a right turn and heading north. Although this looks odd, it is not unusual for a late-season storm. We saw it in 2005 with Hurricane Wilma, which ended up making landfall in southwestern Florida and crossing the state. It's really too soon for me to tell but just so you know a possible reason behind such a sharp turn - <weather science alert> it's because a low front is forecast to come down from the northwest, and will whisk the storm away along its frontal boundary and towards the northeast. A forecast track like this depends on three things:
1. If there is such a front,
2. if that front is strong enough relative to the storm to have an impact, and
3. where that front is when it meets the storm.
If the front moves faster than forecast, the sharp bend could occur sooner. If it is slower, a weak storm could dissipate over land and not be affected at all. Or a stronger storm could get farther north before turning. <end of weather science alert>
Until tomorrow my friends!
Ciao,
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Tropical Depression Lisa:
The ultimate boomerang storm! Lisa formed near the Cape Verde Islands, headed west/northwest for a few days lulling the residents of the Cape Verde Islands into a false sense of security and sunshine, and has now returned to drop off some rain she forgot to leave the last time she was in the area. But at least she's been downgraded to a Tropical Depression because of that low pressure front to the northeast that I mentioned yesterday. She's around 17.5N, 28.9W and moving N at hardly any speed at all (2mph). Winds are 35mph and central pressure is 1002mb. Vorticity is still really good in the lowest half of the troposphere, but the convection just isn't there right now. The NHC think she might get back to being a Tropical Storm, but she won't be very strong and will stay in the Atlantic - I see nothing to disagree with in that assessment.
Tropical Depression 15:
This is the former Caribbean Blob. It was upgraded a few hours ago and is currently centered at 13.9N, 76.2W and is moving W at 15mph. Winds are 35mph and the central pressure is 1007mb. Convection has been really strong over much of the Caribbean because of this blob. I sure hope no-one is trying to get a tan on the deck of a cruise ship in the Caribbean this week! The vorticity (circulation) has slowly improved over the lowest half of the troposphere, but there's nothing higher up (which is a good thing). Although the official direction of movement is West, I think it's moving WNW and has started to move away from the South American landmass. I also think the forecast track on the NHC page is reasonable until a point. I think that it will continue to head WNW/NW towards the Nicaragua/Honduras region, and then possibly on to Belize and Mexico. It continues to experience a bit of wind shear, which is still why the development is slow. However water temperatures are rather warm at around 28-30 deg C and the warm waters of over 26.5 deg C can be found in the upper 75-100m. As it gets closer to Central America it will be closer to the deepest warm water in the ocean and, depending on it's proximity to land and how much wind shear there is, we might see it blossom like it's brother, Karl. The forecast track gets interesting after Monday (when it is over the Yucatan) - the forecast shows it doing a right turn and heading north. Although this looks odd, it is not unusual for a late-season storm. We saw it in 2005 with Hurricane Wilma, which ended up making landfall in southwestern Florida and crossing the state. It's really too soon for me to tell but just so you know a possible reason behind such a sharp turn - <weather science alert> it's because a low front is forecast to come down from the northwest, and will whisk the storm away along its frontal boundary and towards the northeast. A forecast track like this depends on three things:
1. If there is such a front,
2. if that front is strong enough relative to the storm to have an impact, and
3. where that front is when it meets the storm.
If the front moves faster than forecast, the sharp bend could occur sooner. If it is slower, a weak storm could dissipate over land and not be affected at all. Or a stronger storm could get farther north before turning. <end of weather science alert>
Until tomorrow my friends!
Ciao,
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Wednesday, September 22, 2010
Post-Ex-Igor, Tropical Storm Lisa and the Caribbean Blob: September 22, Update A
Aww... northeastern Canada took a bit of a beating from the extratropical Igor/low front morphed storm. It looks like it might be the storm of the century for them! It caused a lot of damage and certainly will be talked about, probably for the next 100 years. Even though it was a lot weaker than when it passed Bermuda, the northern latitudes are not as used to such storms on an annual basis. The Canadian Broadcasting Corportation has post-storm updates and photos posted at http://www.cbc.ca/nl/blogs/seen/stormcentre.html. I believe the little bit of remaining rain and the still rather strong winds have now shifted towards Greenland.
Tropical Storm Lisa:
Lisa has been spinning her wheels all day! ;-) She's been stuck more-or-less in the same spot for over 24 hours, resulting in a decrease in underlying sea surface temperatures from about 26-27 deg C to 25-26 deg C (an estimate). Her convection has decreased since yesterday. Officially her current location is 17.7N, 30.5W and she's moving E at 3mph and officially winds have been kept at 45 mph, making her a very weak Tropical Storm (range: 39-73mph). Her estimated central pressure is 1002mb. I think it is possible that she is moving NE, and is at something like 17.9N, 29.6W. The circulation (vorticity) is interesting. She still has the vorticity I would associate with a Tropical Storm in the lowest levels of the troposphere, but at mid-levels it looks like she is now connected to a low pressure front that extends off to the northeast. You can see this in satellite images. I've included a picture on the blog site... because I can :-) (it just tickles me that I can put pictures on there. It's the little things in life. ;-)). In the picture (taken by the METEOSAT-8 satellite) Lisa is the red dot (heavy convection) at about 18N, 30W (this was taken at 18:00 UTC, which is 1pm in the afternoon EST). The front is marked by the stream of blue and yellow convective area streaming off to the northeast. There's a chance she'll head northeast and get absorbed into that front. The NHC forecast has her moving NW and dissipating in the mid-Atlantic by Monday.
Caribbean Blob:
The chance of this developing into a tropical cyclone in the next 2 days is now officially 60%. The vorticity has slowly improved in the lower half of the troposphere today but it is just clipping the northern edge of South America, which I think is one reason it has been slow to develop. The other reason is that there is a bit of wind shear. It is difficult to tell if it will get a chance to fully develop in the Caribbean because if it continues to go west it will reach Central America and possibly cross into the Pacific before it forms into a proper storm. Yesterday I was thinking that it might head north towards the Hispaniola/Cuba region, but I see today that there are a line of clouds and thunderstorms that stretch from this blob towards Cuba, so maybe that is what I was seeing. Whether the area of higher vorticity follows that or not, I can't tell yet. It needs to move away from land really before it can develop.
Umm, gosh... I think that's it for today. All this time left! I can go and stare at a wall now. How exciting! ;-)
A bientot,
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Tropical Storm Lisa:
Lisa has been spinning her wheels all day! ;-) She's been stuck more-or-less in the same spot for over 24 hours, resulting in a decrease in underlying sea surface temperatures from about 26-27 deg C to 25-26 deg C (an estimate). Her convection has decreased since yesterday. Officially her current location is 17.7N, 30.5W and she's moving E at 3mph and officially winds have been kept at 45 mph, making her a very weak Tropical Storm (range: 39-73mph). Her estimated central pressure is 1002mb. I think it is possible that she is moving NE, and is at something like 17.9N, 29.6W. The circulation (vorticity) is interesting. She still has the vorticity I would associate with a Tropical Storm in the lowest levels of the troposphere, but at mid-levels it looks like she is now connected to a low pressure front that extends off to the northeast. You can see this in satellite images. I've included a picture on the blog site... because I can :-) (it just tickles me that I can put pictures on there. It's the little things in life. ;-)). In the picture (taken by the METEOSAT-8 satellite) Lisa is the red dot (heavy convection) at about 18N, 30W (this was taken at 18:00 UTC, which is 1pm in the afternoon EST). The front is marked by the stream of blue and yellow convective area streaming off to the northeast. There's a chance she'll head northeast and get absorbed into that front. The NHC forecast has her moving NW and dissipating in the mid-Atlantic by Monday.
Caribbean Blob:
The chance of this developing into a tropical cyclone in the next 2 days is now officially 60%. The vorticity has slowly improved in the lower half of the troposphere today but it is just clipping the northern edge of South America, which I think is one reason it has been slow to develop. The other reason is that there is a bit of wind shear. It is difficult to tell if it will get a chance to fully develop in the Caribbean because if it continues to go west it will reach Central America and possibly cross into the Pacific before it forms into a proper storm. Yesterday I was thinking that it might head north towards the Hispaniola/Cuba region, but I see today that there are a line of clouds and thunderstorms that stretch from this blob towards Cuba, so maybe that is what I was seeing. Whether the area of higher vorticity follows that or not, I can't tell yet. It needs to move away from land really before it can develop.
Umm, gosh... I think that's it for today. All this time left! I can go and stare at a wall now. How exciting! ;-)
A bientot,
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Tuesday, September 21, 2010
'Hurricane' Igor, Tropical Storm Lisa, and the Caribbean Blob: September 21, Update A
Let's see, it's September 21 and we have a new storm, Lisa. On August 21, Danielle was spinning up but not named. D, E, F, ... <a few more letters>... K, L. That's 9 storms in the past month. I don't think that's a record, but phew! I can't remember what it's like to just plonk oneself down in front of the telly... maybe because I haven't had a TV for a couple of years. Ok, I can't remember what it's like to just plonk oneself down in front of a blank wall....
Hurricane Igor:
Eeek... Igor's gone postal!!! Oh wait. Sorry. That's not quite the NHC headline. I mis-read. Oops. The actual headline is: IGOR BECOMES POST-TROPICAL. He's at 49.3N, 51.7W and in Canada (Newfoundland), so yes, I agree he's not 'Tropical'. I learned that Canada wasn't in the tropics when I was about 6 and it's a relief to know that piece of knowledge is finally paying off. ;-) Winds are 80mph, central pressure is still a very very low 950mb, and he's moving NNE at a rapid 39mph, but all of that is because he's actually part of a low pressure front now and hence an *extratropical* storm. Hurricane force winds (greater than 73mph) can be felt up to 80 miles from the 'center' and tropical force winds (39mph or higher) can be felt up to 520 miles from the center. Although he's still marked as a hurricane and then Tropical Storm until the end of this week (when he more-or-less reaches the Arctic !!), the NHC have stopped their advisories on this system because he's no longer Tropical... and therefore not topical. ;-) That's fine with me. If anyone wants to know what's going on 'up north' in more detail than my assessment of 'a bit of rain with very windy weather', visit the Canadian Met Service (http://www.weatheroffice.gc.ca/canada_e.html). This is my last entry on Eager Igor. Oh happy day!
Tropical Storm Lisa:
We have another named tropical storm. I am not surprised, and neither should you be. *We* knew it was a Tropical Depression for over a day. Lisa is in the eastern Atlantic, and has estimated winds of 45mph and a central pressure of 1002mb. She's almost stationary, even though officially she's 'moving' (crawling) in a northward direction at 2mph. She's centered at 18.3N, 31.6W. She's not very well organized so I'm not 100% convinced that is the center of circulation. Looks to me like it could be anywhere between 17.5-18.5N and 30-32W, but I'll go with the official word for now. She has a lot of vorticity in the lowest half of the troposphere - definitely the signal of a strong Tropical Storm, if not the start of a hurricane. Certainly stronger than her current official estimated strength. Convection has been waxing and waning all day though. Despite a small vorticity signal in the upper troposphere (further indicating potential hurricane development), until she gets her convection organized she won't get much stronger. The NHC forecast has her as a hurricane in just over a day. I can see that, provided the convection is there. The long term track is all over the place - it's difficult at the moment because she's not really moving anywhere and she's not very strong. I'll look into my tea leaves tomorrow.
Caribbean Blob:
This blob has been raining and thundering all over the eastern Caribbean for a couple of days, and today it finally began to get its vorticity sorted out. At the moment there's some weak circulation (vorticity) in the lowest levels of the troposphere, but nothing at the mid-to-upper levels. It's moving westward at 15mph and is really close to the South American landmass. We'll see how it develops. I don't think we'll see too much tomorrow but I'll check in with an update on it anyway. The next name is Matthew.
That's all. Yes, a nice and easy day! There's even time for a relaxing cup of tea and a nap. ;-)
Toodles!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Hurricane Igor:
Eeek... Igor's gone postal!!! Oh wait. Sorry. That's not quite the NHC headline. I mis-read. Oops. The actual headline is: IGOR BECOMES POST-TROPICAL. He's at 49.3N, 51.7W and in Canada (Newfoundland), so yes, I agree he's not 'Tropical'. I learned that Canada wasn't in the tropics when I was about 6 and it's a relief to know that piece of knowledge is finally paying off. ;-) Winds are 80mph, central pressure is still a very very low 950mb, and he's moving NNE at a rapid 39mph, but all of that is because he's actually part of a low pressure front now and hence an *extratropical* storm. Hurricane force winds (greater than 73mph) can be felt up to 80 miles from the 'center' and tropical force winds (39mph or higher) can be felt up to 520 miles from the center. Although he's still marked as a hurricane and then Tropical Storm until the end of this week (when he more-or-less reaches the Arctic !!), the NHC have stopped their advisories on this system because he's no longer Tropical... and therefore not topical. ;-) That's fine with me. If anyone wants to know what's going on 'up north' in more detail than my assessment of 'a bit of rain with very windy weather', visit the Canadian Met Service (http://www.weatheroffice.gc.ca/canada_e.html). This is my last entry on Eager Igor. Oh happy day!
Tropical Storm Lisa:
We have another named tropical storm. I am not surprised, and neither should you be. *We* knew it was a Tropical Depression for over a day. Lisa is in the eastern Atlantic, and has estimated winds of 45mph and a central pressure of 1002mb. She's almost stationary, even though officially she's 'moving' (crawling) in a northward direction at 2mph. She's centered at 18.3N, 31.6W. She's not very well organized so I'm not 100% convinced that is the center of circulation. Looks to me like it could be anywhere between 17.5-18.5N and 30-32W, but I'll go with the official word for now. She has a lot of vorticity in the lowest half of the troposphere - definitely the signal of a strong Tropical Storm, if not the start of a hurricane. Certainly stronger than her current official estimated strength. Convection has been waxing and waning all day though. Despite a small vorticity signal in the upper troposphere (further indicating potential hurricane development), until she gets her convection organized she won't get much stronger. The NHC forecast has her as a hurricane in just over a day. I can see that, provided the convection is there. The long term track is all over the place - it's difficult at the moment because she's not really moving anywhere and she's not very strong. I'll look into my tea leaves tomorrow.
Caribbean Blob:
This blob has been raining and thundering all over the eastern Caribbean for a couple of days, and today it finally began to get its vorticity sorted out. At the moment there's some weak circulation (vorticity) in the lowest levels of the troposphere, but nothing at the mid-to-upper levels. It's moving westward at 15mph and is really close to the South American landmass. We'll see how it develops. I don't think we'll see too much tomorrow but I'll check in with an update on it anyway. The next name is Matthew.
That's all. Yes, a nice and easy day! There's even time for a relaxing cup of tea and a nap. ;-)
Toodles!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Monday, September 20, 2010
Hurricane Igor, Tropical Storm Julia, and the Atlantic Blobette: September 20, Update A
I hear that all is more-or-less ok in Bermuda after the storm. I know some parts of the island lost power during the night, but everyone survived and it looks like a lot of the clean up involves assorted bits of trees. I've included a pic or two of the post-storm leafy mess from Steve B. on the blog site (address below), but won't clog up email boxes so if you want a gander, pop over to the blog. No fallen trees or anything quite so dramatic. But I don't envy them the sweeping and raking!
Hurricane Igor:
He's still a hurricane, but winds are only 75mph so he's barely a cat 1 (range: 74-95mph). The NHC have had him at this level for a large chunk of the day. The latest advisory says he is beginning to become an extratropical storm because the convection decreased substantially, his forward speed picked up, and he's becoming elongated along a frontal boundary - i.e. merging into a front. 'Eager Igor' (hee hee, wish I'd thought of that one sooner!) is now racing NE at 28 mph. His center is currently in the vicinity of 38.2N, 61.5W.
Despite the relatively weak storm (low wind speed), his central pressure has been unusually low. It's now at 968mb, but earlier today he had winds of 75mph and an even lower central pressure. This is the lowest central pressure I recall seeing for such a low category storm. I'll go into this and the central pressure/intensity malarky in more detail one day (advance warning of some science! ooh, aah! ;-)).
Newfoundland got some rain, and ... <pause... check google map of Canadian provinces>... so have parts Nova Scotia and Prince Edward Island. ;-) Nothing too bad from the looks of the satellite images. Not really any thunderstorms. They'll get some blustery weather up there... I'm sure it'll be just as nice as any other summer day for them.
The NHC still keep him as a 'post-tropical' cat 1 until Wednesday, and then he'll make landfall as a 'post-tropical' Tropical Storm (!!) in ... umm... Greenland (!) on Thursday, where he'll get thoroughly depressed at the melting ice and leave as a 'post-tropical' Tropical Depression (!!). Hmm... I'm not sure this new nomenclature (jargon) of 'post-tropical Tropical' stuff is quite working for me. Can't we go back to 'he'll become an extratropical storm' and leave it at that?
Tropical Storm Julia:
As for Julia, the latest NHC advisory about Tropical Storm Julia says "JULIA LOSES TROPICAL CHARACTERISTICS". So umm... why persist in calling her a Tropical storm? Why not an extratropical storm or low pressure system with wind speeds of 45mph and a low pressure of 999mb? She's at around 34.7N, 46.4W. That's not in the tropics. That's in the extratropics. And she's more of a low pressure front now than a tropical storm. Oh well. She's moving E at 8mph. She's not very strong at all. This is my last entry on Julia. She did a good thing back there making friends with Igor. It kept him from being too boisterous! :-)
Atlantic Blobette:
This picked up in convective activity today. I am not sure why it's not yet a Tropical Depression. Looks like closed circulation to me. Vorticity is good in the lower troposphere. Ho hum. Maybe tomorrow.
On another note... I got an email about possible Caribbean storms from Teresa F.. Storms tend to develop in the western side of the Atlantic - the Caribbean, the Gulf of Mexico, and the western Atlantic - late in the season (October/November) or early in the season (June/July).
The sun has gone to sleep here, and so must I!
Another batch of ramblings tomorrow. :-)
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Hurricane Igor:
He's still a hurricane, but winds are only 75mph so he's barely a cat 1 (range: 74-95mph). The NHC have had him at this level for a large chunk of the day. The latest advisory says he is beginning to become an extratropical storm because the convection decreased substantially, his forward speed picked up, and he's becoming elongated along a frontal boundary - i.e. merging into a front. 'Eager Igor' (hee hee, wish I'd thought of that one sooner!) is now racing NE at 28 mph. His center is currently in the vicinity of 38.2N, 61.5W.
Despite the relatively weak storm (low wind speed), his central pressure has been unusually low. It's now at 968mb, but earlier today he had winds of 75mph and an even lower central pressure. This is the lowest central pressure I recall seeing for such a low category storm. I'll go into this and the central pressure/intensity malarky in more detail one day (advance warning of some science! ooh, aah! ;-)).
Newfoundland got some rain, and ... <pause... check google map of Canadian provinces>... so have parts Nova Scotia and Prince Edward Island. ;-) Nothing too bad from the looks of the satellite images. Not really any thunderstorms. They'll get some blustery weather up there... I'm sure it'll be just as nice as any other summer day for them.
The NHC still keep him as a 'post-tropical' cat 1 until Wednesday, and then he'll make landfall as a 'post-tropical' Tropical Storm (!!) in ... umm... Greenland (!) on Thursday, where he'll get thoroughly depressed at the melting ice and leave as a 'post-tropical' Tropical Depression (!!). Hmm... I'm not sure this new nomenclature (jargon) of 'post-tropical Tropical' stuff is quite working for me. Can't we go back to 'he'll become an extratropical storm' and leave it at that?
Tropical Storm Julia:
As for Julia, the latest NHC advisory about Tropical Storm Julia says "JULIA LOSES TROPICAL CHARACTERISTICS". So umm... why persist in calling her a Tropical storm? Why not an extratropical storm or low pressure system with wind speeds of 45mph and a low pressure of 999mb? She's at around 34.7N, 46.4W. That's not in the tropics. That's in the extratropics. And she's more of a low pressure front now than a tropical storm. Oh well. She's moving E at 8mph. She's not very strong at all. This is my last entry on Julia. She did a good thing back there making friends with Igor. It kept him from being too boisterous! :-)
Atlantic Blobette:
This picked up in convective activity today. I am not sure why it's not yet a Tropical Depression. Looks like closed circulation to me. Vorticity is good in the lower troposphere. Ho hum. Maybe tomorrow.
On another note... I got an email about possible Caribbean storms from Teresa F.. Storms tend to develop in the western side of the Atlantic - the Caribbean, the Gulf of Mexico, and the western Atlantic - late in the season (October/November) or early in the season (June/July).
The sun has gone to sleep here, and so must I!
Another batch of ramblings tomorrow. :-)
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Sunday, September 19, 2010
Hurricane Igor, Tropical Storm Julia, and the Atlantic Blobette: September 19, Update A
Today is a good day. I didn't meet any wild creatures and things are looking relatively good for Bermuda. Well, much better than they were a couple of days ago anyway.
Hurricane Igor:
Igor's convection has decreased A LOT and he's now a mid-level cat 1 storm with winds of 85mph (cat 1 range: 74-95 mph) and a central pressure of 952mb. He's at 30.8 N, 65.7W and is moving N at 16mph. His center will pass just west of Bermuda, which means that you guys will get a batch of really strong winds and thunderstorms, but after that it'll die down rapidly because he's not really got much convective activity on his southern side - it's just cloudy and windy. Not even much rain. I'm guessing another 7-10 hours and the main part of him will have passed by. He's still got high vorticity (circulation) in the lowest half of the troposphere, but it is slowly decreasing in the upper levels. Sea surface temperatures are 26-27 deg C.The lack of convection to the south is from a combination of wind shear from the south and also dry air and the farther north he gets, the more wind shear he's going to experience and of course, the colder the water gets.
From Steve B. (on Bermuda):
at 2.10pm (local time): " just went for walk in rain. very wet and a little windy. warm, so good walking conditions."
at 6.10pm (local time): " i am tired of this storm. it's windy"
I think he might be a bit bored. He's reading about heat transfer. And we are discussing whether latent heat processes belong in the field of chemistry or physics. I think we've got as far as agreeing that 'the Sun is important'. It's all very profound and philosophical stuff. ;-)
The NHC have Igor as a cat 1 hurricane until Wednesday morning, when it reaches the northern North Atlantic where water temperatures are less than 24 deg C - far too cold to sustain a storm. I think that might be keeping him at that level too long and it should deteriorate before then. They might keep him at that level because they do things like that but he won't be a tropical storm, he'll be an extra-tropical storm (or post-tropical or whatever the new lingo is this year).
Tropical Storm Julia:
She's still a mid-to-weak Tropical Storm with winds of 50mph and an estimated central pressure of 998mb. She's zipping off in an East-Northeast direction at 15mph and is currently centered at 34.2N, 50.3W. There is still some convection - and although it's not as wide-spread as Igor's, it is actually stronger. The vorticity has decreased a lot in this system and is now only strong in the lowest half of the troposphere. She's still undergoing wind shear from Igor as well. She's forecast to dissipate by Tuesday morning. It all seems quite reasonable to me.
Atlantic Blobette:
I mention it now because it's certainly improved in structure today and circulation looks good in the lowest half of the troposphere. It looks like a Tropical Depression to me, even though the NHC still have it marked at the 80% level of storm formation. Convection is also slowly improving. I think the center is somewhere around 15.5-16N, 31W, and it's moving generally northwestward at 5mph. They anticipate upgrading it to a Tropical Depression tonight or tomorrow. I'll look at pressure fields etc when it's a TD.
So for my Bermudian friends, the worst weather is almost there but after that it should get better quickly. (And hello to the new Bermudian readers - Helene M. told me there are more people on the island reading this than I previously suspected! I hope you were sufficiently warned about my <ahem> intellectual and <ahem> literary writing! ;-) )
Be safe!
More tomorrow.
J.
p.s. I did manage to post a picture on the blog site! It IS a new era. Let's see... I think I shall call it 'The dawning of the Age of Aquarius' (because I am one). Surely no-one has thought of that before, have they?
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Hurricane Igor:
Igor's convection has decreased A LOT and he's now a mid-level cat 1 storm with winds of 85mph (cat 1 range: 74-95 mph) and a central pressure of 952mb. He's at 30.8 N, 65.7W and is moving N at 16mph. His center will pass just west of Bermuda, which means that you guys will get a batch of really strong winds and thunderstorms, but after that it'll die down rapidly because he's not really got much convective activity on his southern side - it's just cloudy and windy. Not even much rain. I'm guessing another 7-10 hours and the main part of him will have passed by. He's still got high vorticity (circulation) in the lowest half of the troposphere, but it is slowly decreasing in the upper levels. Sea surface temperatures are 26-27 deg C.The lack of convection to the south is from a combination of wind shear from the south and also dry air and the farther north he gets, the more wind shear he's going to experience and of course, the colder the water gets.
From Steve B. (on Bermuda):
at 2.10pm (local time): " just went for walk in rain. very wet and a little windy. warm, so good walking conditions."
at 6.10pm (local time): " i am tired of this storm. it's windy"
I think he might be a bit bored. He's reading about heat transfer. And we are discussing whether latent heat processes belong in the field of chemistry or physics. I think we've got as far as agreeing that 'the Sun is important'. It's all very profound and philosophical stuff. ;-)
The NHC have Igor as a cat 1 hurricane until Wednesday morning, when it reaches the northern North Atlantic where water temperatures are less than 24 deg C - far too cold to sustain a storm. I think that might be keeping him at that level too long and it should deteriorate before then. They might keep him at that level because they do things like that but he won't be a tropical storm, he'll be an extra-tropical storm (or post-tropical or whatever the new lingo is this year).
Tropical Storm Julia:
She's still a mid-to-weak Tropical Storm with winds of 50mph and an estimated central pressure of 998mb. She's zipping off in an East-Northeast direction at 15mph and is currently centered at 34.2N, 50.3W. There is still some convection - and although it's not as wide-spread as Igor's, it is actually stronger. The vorticity has decreased a lot in this system and is now only strong in the lowest half of the troposphere. She's still undergoing wind shear from Igor as well. She's forecast to dissipate by Tuesday morning. It all seems quite reasonable to me.
Atlantic Blobette:
I mention it now because it's certainly improved in structure today and circulation looks good in the lowest half of the troposphere. It looks like a Tropical Depression to me, even though the NHC still have it marked at the 80% level of storm formation. Convection is also slowly improving. I think the center is somewhere around 15.5-16N, 31W, and it's moving generally northwestward at 5mph. They anticipate upgrading it to a Tropical Depression tonight or tomorrow. I'll look at pressure fields etc when it's a TD.
So for my Bermudian friends, the worst weather is almost there but after that it should get better quickly. (And hello to the new Bermudian readers - Helene M. told me there are more people on the island reading this than I previously suspected! I hope you were sufficiently warned about my <ahem> intellectual and <ahem> literary writing! ;-) )
Be safe!
More tomorrow.
J.
p.s. I did manage to post a picture on the blog site! It IS a new era. Let's see... I think I shall call it 'The dawning of the Age of Aquarius' (because I am one). Surely no-one has thought of that before, have they?
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Saturday, September 18, 2010
Hurricane Igor, Tropical Storm Julia, ex-storm Karl, and the Atlantic Blobette: September 18, Update A
Here we go. After days and days of waiting, the outer bands and wind from Igor have reached Bermuda.
Hurricane Igor:
He's still a big storm in spatial extent, but meeting a girl-storm (Julia) softened his 'I'm a tough guy' act so he's now officially a low-to-mid sized cat 2 with winds of 100mph (cat 2 range: 96-110mph) and a central pressure of 945mb. Unfortunately she couldn't persuade him to move away from the path he'd decided to follow so he's still aiming for the Bermuda region. Sigh. He's currently centered at 27.1N, 64.3W and is still moving NW (alas) at 14mph. Hurricane force winds can be felt up to 90 miles from the center, and Tropical Storm force winds up to 345 miles. He's 360 miles south of Bermuda. You can do the maths.
Although the wind speed has dropped to a mere 100 mph (!!!) and he's a low-to-mid cat 2, there are still two things that will make him feel stronger. First, he's a big storm. It's one thing to have a small or quick storm pass by, but another to have a large or slow storm because the winds will be hanging out for longer. The other thing to watch out for with Igor is that his convective activity is really rather strong. The temperature of the cloud tops indicate how deep the convection is in the atmosphere, so the colder the cloud tops, the more thunderstorms, heavy rain, etc. If you look at Infra-red satellite images (e.g. http://www.ssd.noaa.gov/goes/flt/t1/avn-l.jpg), the red and dark grey colours indicate cold temperatures and therefore areas where the convection is really strong. Blue colours are warm (I know, I know, it's not quite what you were taught when you were learning your colours as a kid), and generally indicate areas where it's just cloudy, no rain. Yellow and orange are rain - some light, some heavy, dotted with a few thunderstorms here and there. The hurricane category is just based on wind speed, and doesn't really take into consideration the severity of the convection.
On-the-ground conditions update from Steve B. on Bermuda:
3pm local Bermuda time: "we have ominous clouds. we wait in trepidation. novelty turns to nervousness"
8.25pm local time: "just went outside and moved car away from Casurina trees. Now seems high winds (altitude) and breezy below."
9.37pm: "feels like a storm. we'll muddle through."
As the NHC says, conditions will continue to deteriorate on Bermuda and the center won't get to that vicinity for another 36 or so hours... it's going to be a long few days for you guys! Officially he's not forecast to re-strengthen too much more because, as I mentioned yesterday, he's already getting some wind shear to the north and he's also being truncated to the east by Julia. His vorticity is still very strong throughout the troposphere, so really he's probably got the vorticity of a cat 3 or higher storm, but Julia is really messing things up for him. I don't know how the next couple of days will play out given their interaction, but personally I'd prefer to see that vorticity come down a bit before I say that he's going to be a cat 2 or less.
If you are reading this on the listserve, I've attached a GOES satellite image that shows Igor and Julia. They look like two halves of the same storm, with a big gap in between where the winds are all sorts of squirly (a non-technical term ;-)) and there isn't any convection. If you are reading this on the blog site, I'm going to try and add a picture. My first ever! After all these years of words only! This could usher in a new era! Yes... I might finally reach the advanced technical capabilities of bloggers from circa 2002! How thrilling! (umm... don't hold your breath waiting though! ;-)).
Tropical Storm Julia:
She's now officially got winds of 50mph and a central pressure of 998mb, making her a weak Tropical Storm (range: 39-73mph). Like Igor, although wind speeds are low there is still a lot of convection and her vorticity is still strong in the lowest half of the troposphere - much too strong for a normal low-level Tropical Storm, but things are a little murky because of Igor. She's moving NNW at 20mph, and is located at about 30.6N, 51.8W.
Ex-storm Karl:
Karl dissipated over the mountains of central Mexico today after dumping a lot of rain. There is a lot of convection in the western Gulf of Mexico, which may or may not be his final swan-song. I don't know because I didn't see his demise and subsequent data because I was away from a computer all day today (trying to avoid stepping on a wild poisonous snake that was sunning itself on a well-walked path!!! Yes, in the UK! I know, it's an unbelivable tale because I mention sun and UK in consecutive sentences... ;-)) Ummm... so, yes, storm. I don't know if the convection in the Gulf is connected to the vorcity signature from Karl or not. But the convection in qustion is right along the western edge of the Gulf and should move west over land before it develops much. In this I agree with the NHC. It will dump a lot of rain on Texas and Mexico (because that's just what they need after the soaking they got from Karl). Anyway, this is my last entry on Karl.
Atlantic Blobette:
Yup, another one. This entry is just a heads-up. There is some circulation in the lowest levels of the troposphere but it's not very well structured at the moment. There is also some convection with this blobette. Next name is Lisa, but I'm not going to mention this again until it does something worth mentioning.
That's it for now. Be safe in Bermuda!!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Hurricane Igor:
He's still a big storm in spatial extent, but meeting a girl-storm (Julia) softened his 'I'm a tough guy' act so he's now officially a low-to-mid sized cat 2 with winds of 100mph (cat 2 range: 96-110mph) and a central pressure of 945mb. Unfortunately she couldn't persuade him to move away from the path he'd decided to follow so he's still aiming for the Bermuda region. Sigh. He's currently centered at 27.1N, 64.3W and is still moving NW (alas) at 14mph. Hurricane force winds can be felt up to 90 miles from the center, and Tropical Storm force winds up to 345 miles. He's 360 miles south of Bermuda. You can do the maths.
Although the wind speed has dropped to a mere 100 mph (!!!) and he's a low-to-mid cat 2, there are still two things that will make him feel stronger. First, he's a big storm. It's one thing to have a small or quick storm pass by, but another to have a large or slow storm because the winds will be hanging out for longer. The other thing to watch out for with Igor is that his convective activity is really rather strong. The temperature of the cloud tops indicate how deep the convection is in the atmosphere, so the colder the cloud tops, the more thunderstorms, heavy rain, etc. If you look at Infra-red satellite images (e.g. http://www.ssd.noaa.gov/goes/flt/t1/avn-l.jpg), the red and dark grey colours indicate cold temperatures and therefore areas where the convection is really strong. Blue colours are warm (I know, I know, it's not quite what you were taught when you were learning your colours as a kid), and generally indicate areas where it's just cloudy, no rain. Yellow and orange are rain - some light, some heavy, dotted with a few thunderstorms here and there. The hurricane category is just based on wind speed, and doesn't really take into consideration the severity of the convection.
On-the-ground conditions update from Steve B. on Bermuda:
3pm local Bermuda time: "we have ominous clouds. we wait in trepidation. novelty turns to nervousness"
8.25pm local time: "just went outside and moved car away from Casurina trees. Now seems high winds (altitude) and breezy below."
9.37pm: "feels like a storm. we'll muddle through."
As the NHC says, conditions will continue to deteriorate on Bermuda and the center won't get to that vicinity for another 36 or so hours... it's going to be a long few days for you guys! Officially he's not forecast to re-strengthen too much more because, as I mentioned yesterday, he's already getting some wind shear to the north and he's also being truncated to the east by Julia. His vorticity is still very strong throughout the troposphere, so really he's probably got the vorticity of a cat 3 or higher storm, but Julia is really messing things up for him. I don't know how the next couple of days will play out given their interaction, but personally I'd prefer to see that vorticity come down a bit before I say that he's going to be a cat 2 or less.
If you are reading this on the listserve, I've attached a GOES satellite image that shows Igor and Julia. They look like two halves of the same storm, with a big gap in between where the winds are all sorts of squirly (a non-technical term ;-)) and there isn't any convection. If you are reading this on the blog site, I'm going to try and add a picture. My first ever! After all these years of words only! This could usher in a new era! Yes... I might finally reach the advanced technical capabilities of bloggers from circa 2002! How thrilling! (umm... don't hold your breath waiting though! ;-)).
Tropical Storm Julia:
She's now officially got winds of 50mph and a central pressure of 998mb, making her a weak Tropical Storm (range: 39-73mph). Like Igor, although wind speeds are low there is still a lot of convection and her vorticity is still strong in the lowest half of the troposphere - much too strong for a normal low-level Tropical Storm, but things are a little murky because of Igor. She's moving NNW at 20mph, and is located at about 30.6N, 51.8W.
Ex-storm Karl:
Karl dissipated over the mountains of central Mexico today after dumping a lot of rain. There is a lot of convection in the western Gulf of Mexico, which may or may not be his final swan-song. I don't know because I didn't see his demise and subsequent data because I was away from a computer all day today (trying to avoid stepping on a wild poisonous snake that was sunning itself on a well-walked path!!! Yes, in the UK! I know, it's an unbelivable tale because I mention sun and UK in consecutive sentences... ;-)) Ummm... so, yes, storm. I don't know if the convection in the Gulf is connected to the vorcity signature from Karl or not. But the convection in qustion is right along the western edge of the Gulf and should move west over land before it develops much. In this I agree with the NHC. It will dump a lot of rain on Texas and Mexico (because that's just what they need after the soaking they got from Karl). Anyway, this is my last entry on Karl.
Atlantic Blobette:
Yup, another one. This entry is just a heads-up. There is some circulation in the lowest levels of the troposphere but it's not very well structured at the moment. There is also some convection with this blobette. Next name is Lisa, but I'm not going to mention this again until it does something worth mentioning.
That's it for now. Be safe in Bermuda!!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Friday, September 17, 2010
Hurricanes Igor, Julia and Karl: September 17, Update A
Another interesting day out there. Not quite as interesting as I was hoping regarding Igor and Julia, but more interesting than I was expecting regarding Karl!
Hurricane Igor:
After the plane returned data from Igor yesterday the NHC downgraded him to a strong cat 3, which is what I thought they would find. He's been slowly decreasing in strength and, based on the latest Hurricane Hunter plane observations, he is currently a strong cat 2 storm with winds of 105mph (cat 2 range: 96 - 110mph) and a central pressure of 947mb. He's moving NW at 10mph and officially his center is at 23.7N, 61.1W. It looks to me as though he's about 0.5 degree east of this - at 23.7N, 60.7W, but the satellite image I have is a couple of hours old, so maybe he took a sharp westward turn in the past couple of hours. Still, he's generally doing the NW path thing, but is forecast to turn NNW tomorrow afternoon and then North - the sooner he makes that turn, the better for Bermuda.
Spatially, Igor is HUGE! From north to south his outer bands cover something like 1200 miles! So although his center is 665 miles SSE of Bermuda, everyone from Bermuda to the Leeward Islands in the Caribbean are feeling some effects from Igor. Fortunately there aren't too many people in that area, mostly fish and possibly some aliens, depending on what you believe about the Bermuda Triangle ;-). Hurricane force winds (greater than 73mph) can be felt up to 105 miles from the center, and tropical storm force winds extend out 345 miles. Vorticity is still very strong throughout the troposphere for Igor, which means there's a small chance he could get a little stronger before weakening (this is in agreement with the NHC). Convection is also quite good too - plenty of thunder and lightning and stuff closer to the center. There is some wind shear affecting his northern edge and you can see that in the satellite images as clouds stream off to the northeast. As he moves farther north, this shear will be a greater impact so he shouldn't get too strong by the time he gets that far north (past Bermuda).
A hurricane warning was issued for Bermuda earlier today (about 3-4 hours ago), meaning they will get Tropical Force winds (greater than 39mph) within the next 36 hours. The current center of cone track does take the eye close to Bermuda.
Dear Igor, I would like you to shift to the east a smidge and turn NNW tomorrow morning. Or overnight. Thank you.
Hurricane Julia:
Again as I expected yesterday, they downgraded her intensity quite rapidly to a cat 1 (range: 74-95mph), and then gradually decreased it after that. I won't bother telling you my opinion, cos you can read it in the last two entries if you missed it. I've recovered now. ;-)
She's still being held as a cat 1 storm, but barely, with winds of 75mph and an estimated central pressure of 987mb. I think this is perfectly acceptable. Her vorticity (circulation) is still strong in the lowest half of the troposphere, but her convection has decreased a lot.
I was so hoping she'd do a little dance with Igor today and we'd see the Fujiwhara interaction in all it's glory because that would have been so cool, but it looks like she was just too little compared to Igor and instead she reminded me of a tree trunk meeting a wood chipper... any time she got close to the swirling saw of Igor's winds her clouds kept getting lopped off so she got smaller and smaller. Maybe there will be a little of the Fujiwhara effect still though, and maybe she will tug Igor to the east a bit. We'll see. (I'm remain optimistic!). However, in her limited interactions with Igor I think she still did us all a favour because I think that's what helped to bring Igor's intensity down. He didn't (and still doesn't) have much room to expand on his east side (outflow was inhibited).
She's currently at 25.2N, 48.2W, moving WNW at 18mph.
Hurricane Karl:
As well behaved as Igor and Julia have been today, bad boy Karl more than made up for that! He turned into a cat 3 storm!! I was wrong in thinking he'd remain a cat 1. The vorticity still wasn't strong enough to support a cat 3 storm, but he definitely had a lot of convection and a good looking eye. I'm thinking that there is a piece of this intensification that is connected solely to the convection which he really picked up before he crossed the Yucatan, but interestingly, he also got from the entire western Gulf despite being so far south. He was actually also a large storm spatially, and although he was in the Bay of Campeche (I think is the southernmost cat 3 storm detected so far) he was affecting the atmosphere as far as the northern Gulf (clouds and some rain). We were just really really lucky that he was partly over land, otherwise he would have been a monster storm!
He made landfall just north-northwest of Veracruz, Mexico this morning (around 9.30 or 10.30 am local time). He generally remained south of the forecast center of cone track. He's over land now and they still have him as a strong cat 1 hurricane with winds of 90mph (cat 1 range: 74-95mph) with a central pressure of 985mb. I'd agree with a strong cat 1 at this stage. He is at 19.1N, 96.6W and is moving WSW at 9mph.
He's forecast to decrease in intensity as one would expect over land, and then dissipate by Sunday as he gets to the mountains in Mexico. I think this is a likely scenario, but his vorticity is still quite strong in the lowest half of the troposphere, and there is still a signal in the upper troposphere, even though he is over land. Something to keep an eye on (but not a hurricane eye! ;-)).
More fun and games from the Atlantic tomorrow... where we might have another Blobette in the making (you didn't really think we were done yet, did you?).
Adios amigos!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Hurricane Igor:
After the plane returned data from Igor yesterday the NHC downgraded him to a strong cat 3, which is what I thought they would find. He's been slowly decreasing in strength and, based on the latest Hurricane Hunter plane observations, he is currently a strong cat 2 storm with winds of 105mph (cat 2 range: 96 - 110mph) and a central pressure of 947mb. He's moving NW at 10mph and officially his center is at 23.7N, 61.1W. It looks to me as though he's about 0.5 degree east of this - at 23.7N, 60.7W, but the satellite image I have is a couple of hours old, so maybe he took a sharp westward turn in the past couple of hours. Still, he's generally doing the NW path thing, but is forecast to turn NNW tomorrow afternoon and then North - the sooner he makes that turn, the better for Bermuda.
Spatially, Igor is HUGE! From north to south his outer bands cover something like 1200 miles! So although his center is 665 miles SSE of Bermuda, everyone from Bermuda to the Leeward Islands in the Caribbean are feeling some effects from Igor. Fortunately there aren't too many people in that area, mostly fish and possibly some aliens, depending on what you believe about the Bermuda Triangle ;-). Hurricane force winds (greater than 73mph) can be felt up to 105 miles from the center, and tropical storm force winds extend out 345 miles. Vorticity is still very strong throughout the troposphere for Igor, which means there's a small chance he could get a little stronger before weakening (this is in agreement with the NHC). Convection is also quite good too - plenty of thunder and lightning and stuff closer to the center. There is some wind shear affecting his northern edge and you can see that in the satellite images as clouds stream off to the northeast. As he moves farther north, this shear will be a greater impact so he shouldn't get too strong by the time he gets that far north (past Bermuda).
A hurricane warning was issued for Bermuda earlier today (about 3-4 hours ago), meaning they will get Tropical Force winds (greater than 39mph) within the next 36 hours. The current center of cone track does take the eye close to Bermuda.
Dear Igor, I would like you to shift to the east a smidge and turn NNW tomorrow morning. Or overnight. Thank you.
Hurricane Julia:
Again as I expected yesterday, they downgraded her intensity quite rapidly to a cat 1 (range: 74-95mph), and then gradually decreased it after that. I won't bother telling you my opinion, cos you can read it in the last two entries if you missed it. I've recovered now. ;-)
She's still being held as a cat 1 storm, but barely, with winds of 75mph and an estimated central pressure of 987mb. I think this is perfectly acceptable. Her vorticity (circulation) is still strong in the lowest half of the troposphere, but her convection has decreased a lot.
I was so hoping she'd do a little dance with Igor today and we'd see the Fujiwhara interaction in all it's glory because that would have been so cool, but it looks like she was just too little compared to Igor and instead she reminded me of a tree trunk meeting a wood chipper... any time she got close to the swirling saw of Igor's winds her clouds kept getting lopped off so she got smaller and smaller. Maybe there will be a little of the Fujiwhara effect still though, and maybe she will tug Igor to the east a bit. We'll see. (I'm remain optimistic!). However, in her limited interactions with Igor I think she still did us all a favour because I think that's what helped to bring Igor's intensity down. He didn't (and still doesn't) have much room to expand on his east side (outflow was inhibited).
She's currently at 25.2N, 48.2W, moving WNW at 18mph.
Hurricane Karl:
As well behaved as Igor and Julia have been today, bad boy Karl more than made up for that! He turned into a cat 3 storm!! I was wrong in thinking he'd remain a cat 1. The vorticity still wasn't strong enough to support a cat 3 storm, but he definitely had a lot of convection and a good looking eye. I'm thinking that there is a piece of this intensification that is connected solely to the convection which he really picked up before he crossed the Yucatan, but interestingly, he also got from the entire western Gulf despite being so far south. He was actually also a large storm spatially, and although he was in the Bay of Campeche (I think is the southernmost cat 3 storm detected so far) he was affecting the atmosphere as far as the northern Gulf (clouds and some rain). We were just really really lucky that he was partly over land, otherwise he would have been a monster storm!
He made landfall just north-northwest of Veracruz, Mexico this morning (around 9.30 or 10.30 am local time). He generally remained south of the forecast center of cone track. He's over land now and they still have him as a strong cat 1 hurricane with winds of 90mph (cat 1 range: 74-95mph) with a central pressure of 985mb. I'd agree with a strong cat 1 at this stage. He is at 19.1N, 96.6W and is moving WSW at 9mph.
He's forecast to decrease in intensity as one would expect over land, and then dissipate by Sunday as he gets to the mountains in Mexico. I think this is a likely scenario, but his vorticity is still quite strong in the lowest half of the troposphere, and there is still a signal in the upper troposphere, even though he is over land. Something to keep an eye on (but not a hurricane eye! ;-)).
More fun and games from the Atlantic tomorrow... where we might have another Blobette in the making (you didn't really think we were done yet, did you?).
Adios amigos!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Thursday, September 16, 2010
Hurricanes Igor, Julia and Karl: September 16, Update A
Boy oh boy, this is going to be a loooong month! So, we have three hurricanes out there and I actually agree that they are all hurricanes! I'm not so keen on the official categories, but the status at least. This is just the 9th time (I think) that we've had three active hurricanes at the same time since records began (1851), the last time being in 1998. The caveat to this (hence the 'I think') is that we didn't really know what was going on in the eastern Atlantic until around the 1940s, when planes flew across the remote parts of the ocean basin. In 1998 we actually had four simultaneously active hurricanes: Georges, Ivan, Jeanne, and Karl. And if you are reading this on my blog page (link is below if you want to check it out), the satellite image slice at the top is from 2004 and from left to right you see the fully formed Hurricane Ivan, the northern edge of the almost-developed Hurricane Jeanne, and the African Easterly Wave that became Hurricane Karl! Obviously Karl is a sociable fellow and likes to hang out with his 'peeps'. ;-)
Hurricane Igor:
Igor is still a big storm and holding onto that cat 4 mantle. There are some fluctuations, which are to be expected, but currently his estimated winds are about 140mph so he's a mid-sized cat 4 (range: 131-155mph), with an estimated central pressure of 934mb. His center is currently at 21.5N, 57.6W and he is moving NW at 7mph.
I agree with the NW track for now. The intensity might be a fraction too high, but he still has a pretty good eye so a strong cat 3 or weak cat 4 is where I'd place him. He's experiencing a little bit of wind shear from the northwest, which you can see in the satellite images because the eye is just a bit closer to the northwestern edge. Although the shear is not strong its enough to allow some dry air into the system, which continues to inhibit his growth. Once that shear goes he's got enough oomph to get stronger again. A plane will be sent into the system today to get a better reading of what's going on.
In the back of my head is a little voice that's wondering if he's going to slow down a bit or move a bit more westward. It looked like there was an area of higher pressure in front of him, but I don't have high enough resolution pressure field data to be sure. I guess we'll find out tomorrow. In either case, it'll be a close pass by Bermuda on Sunday (or possibly Monday if he slows down).
Hurricane Julia:
I agree she's a hurricane, but only just. I still completely disagree with the category! She's not had an eye all day, and the wind shear was so strong that most of the convection was to her northeast. Not only that, but the convection consists of a bit of rain with hardly any thunderstorms. Daily summer showers in the tropics have more to them! The only reason I'd put her as a weak cat 1 (if I ruled this gig) would be because she is a bit on the breezy side and has very strong vorticity in the lowest half of the troposphere. The mid-to-upper troposphere does not have the structure of a tropical storm but rather that of a low pressure front.
Anyway, the NHC have steadily decreased her intensity (I am *so* not surprised). She's now officially a weak cat 2 (range: 96-110mph) with estimated winds of 100mph and an estimated central pressure of 971mb. I expect a further decrease in the next advisory or two, down to a cat 1, and then gradually downward. She's centered at 22.4N, 38.6W and is moving WNW at a whopping 25mph (hmm... usually the sort of speeds one sees when a storm is embedded in a front...hmm... funny that).
About her future track. This might get interesting. We'll see how close she gets to Igor because that will affect how strong she remains and whether or not she survives as a stand-alone storm. There's a small chance we'll see the Fujiwhara effect yet (see http://jyotikastorms.blogspot.com/2010/08/hurricane-earl-tropical-storm-fiona.html). That would be SO COOL! (although it might be a bit of a mess in terms of forecasting and storms and whatnot). We'll know in the next couple of days.
Hurricane Karl:
As I said yesterday, I think this little guy's intensity was underestimated before landfall and they continued to underestimate him until they sent in a plane to investigate earlier today (over the Gulf). I think he was a cat 1 at landfall, because he downgraded as he crossed the Yucatan Peninsula to a Tropical Storm, which was his status in as he emerged into the Gulf. If he was a TS, he'd have been a Tropical Depression by the time he reached the Gulf. Anyway, he got into the southern Gulf today (overnight = local time), and after the plane sent back better information, the NHC quickly bumped him up to a very strong Tropical Storm and then Hurricane shortly thereafter.
Also as I suspected yesterday, he's taken a more southern track than the center of cone forecast had for him initially. He's now at 19.8N, 93.5W and moving W at 12mph (possibly WNW I think). I still think he'll continue to move slightly south of the center of the cone. His central pressure is 983mb with winds of 75mph, making him a weak cat 1 storm (cat 1 range: 74-95mph). Again, I think he's a bit stronger than that, but I don't think he'll get beyond a cat 1. His convection has been very good, but in the last few hours it's started to decrease as he's interacting with land to the south, west and to the east, and he's also experiencing some wind shear from the north. His vorticity (circulation) is good in the lower half of the troposphere, but there's only a small signal in the upper troposphere - the sort we see with a cat 1 storm but not a cat 2.
And there we have the reckoning from today. Wasn't I far more agreeable today? ;-) That wine and ice cream must have worked. ;-)
Until tomorrow!
Toodle pip!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Hurricane Igor:
Igor is still a big storm and holding onto that cat 4 mantle. There are some fluctuations, which are to be expected, but currently his estimated winds are about 140mph so he's a mid-sized cat 4 (range: 131-155mph), with an estimated central pressure of 934mb. His center is currently at 21.5N, 57.6W and he is moving NW at 7mph.
I agree with the NW track for now. The intensity might be a fraction too high, but he still has a pretty good eye so a strong cat 3 or weak cat 4 is where I'd place him. He's experiencing a little bit of wind shear from the northwest, which you can see in the satellite images because the eye is just a bit closer to the northwestern edge. Although the shear is not strong its enough to allow some dry air into the system, which continues to inhibit his growth. Once that shear goes he's got enough oomph to get stronger again. A plane will be sent into the system today to get a better reading of what's going on.
In the back of my head is a little voice that's wondering if he's going to slow down a bit or move a bit more westward. It looked like there was an area of higher pressure in front of him, but I don't have high enough resolution pressure field data to be sure. I guess we'll find out tomorrow. In either case, it'll be a close pass by Bermuda on Sunday (or possibly Monday if he slows down).
Hurricane Julia:
I agree she's a hurricane, but only just. I still completely disagree with the category! She's not had an eye all day, and the wind shear was so strong that most of the convection was to her northeast. Not only that, but the convection consists of a bit of rain with hardly any thunderstorms. Daily summer showers in the tropics have more to them! The only reason I'd put her as a weak cat 1 (if I ruled this gig) would be because she is a bit on the breezy side and has very strong vorticity in the lowest half of the troposphere. The mid-to-upper troposphere does not have the structure of a tropical storm but rather that of a low pressure front.
Anyway, the NHC have steadily decreased her intensity (I am *so* not surprised). She's now officially a weak cat 2 (range: 96-110mph) with estimated winds of 100mph and an estimated central pressure of 971mb. I expect a further decrease in the next advisory or two, down to a cat 1, and then gradually downward. She's centered at 22.4N, 38.6W and is moving WNW at a whopping 25mph (hmm... usually the sort of speeds one sees when a storm is embedded in a front...hmm... funny that).
About her future track. This might get interesting. We'll see how close she gets to Igor because that will affect how strong she remains and whether or not she survives as a stand-alone storm. There's a small chance we'll see the Fujiwhara effect yet (see http://jyotikastorms.blogspot.com/2010/08/hurricane-earl-tropical-storm-fiona.html). That would be SO COOL! (although it might be a bit of a mess in terms of forecasting and storms and whatnot). We'll know in the next couple of days.
Hurricane Karl:
As I said yesterday, I think this little guy's intensity was underestimated before landfall and they continued to underestimate him until they sent in a plane to investigate earlier today (over the Gulf). I think he was a cat 1 at landfall, because he downgraded as he crossed the Yucatan Peninsula to a Tropical Storm, which was his status in as he emerged into the Gulf. If he was a TS, he'd have been a Tropical Depression by the time he reached the Gulf. Anyway, he got into the southern Gulf today (overnight = local time), and after the plane sent back better information, the NHC quickly bumped him up to a very strong Tropical Storm and then Hurricane shortly thereafter.
Also as I suspected yesterday, he's taken a more southern track than the center of cone forecast had for him initially. He's now at 19.8N, 93.5W and moving W at 12mph (possibly WNW I think). I still think he'll continue to move slightly south of the center of the cone. His central pressure is 983mb with winds of 75mph, making him a weak cat 1 storm (cat 1 range: 74-95mph). Again, I think he's a bit stronger than that, but I don't think he'll get beyond a cat 1. His convection has been very good, but in the last few hours it's started to decrease as he's interacting with land to the south, west and to the east, and he's also experiencing some wind shear from the north. His vorticity (circulation) is good in the lower half of the troposphere, but there's only a small signal in the upper troposphere - the sort we see with a cat 1 storm but not a cat 2.
And there we have the reckoning from today. Wasn't I far more agreeable today? ;-) That wine and ice cream must have worked. ;-)
Until tomorrow!
Toodle pip!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Wednesday, September 15, 2010
Hurricanes Igor and Julia, Tropical Storm Karl: September 15, Update A
Oh dear. I hardly know where to begin today. A rant? Nope, did that earlier already (in person). Sarcasm? Perhaps. Scientific skepticism? Ok then. Glass of wine? Definitely YES, jolly good idea. :-)
I know the NHC have the most up-to-date and bestest information, and they do an amazing job given the stresses and strains of issuing public forecasts of such magnitude, but today I'm afraid I have to disagree with them on the grounds of umm... er... on the grounds of er... well, just because. And so I do a thorough job of this, I disagree with them on all three Atlantic storms out there today.
Hurricane Igor:
Overnight Igor had 'estimated' winds of 155mph. You might recognize this number. It's the threshold between a Cat 4 and Cat 5 storm. A Cat 5 has winds of 156 mph or higher. The NHC kept him as a Cat 4, but I think for a few hours there he was a cat 5. 1mph in a 155mph storm is well within the error margins and his vorticity was extraordinarily strong. I believe they are reticent to call a storm a cat 5 if they don't have a plane that flies through to provide them in situ (latin for 'in the place') observations ... which might partly explain why cat 5's rarely form outside the recon flight area. Funny coincidence that, don't you think?
Anyway, he's officially been a cat 4 (range: 131-155 mph) all day today. However he has been weakening for the past few hours and personally I'd say that now he is a strong cat 3 (range: 111-130mph) because the eye is no longer clear, but the NHC are being cautious and keeping him as a weak cat 4 with estimated winds of 135mph and a central pressure of 942mb. He's moving WNW at 8mph, and is currently centered at 19.9N, 55.1W (I think he's moving NW, but that's just me). He's still about 1055 miles southeast of Bermuda, with hurricane force winds found up to 45 miles from the centre, and tropical storm force winds out to 225 miles.
He is moving slightly to the east of the center of cone track, which will take him east of Bermuda. If that trend continues and he carries on weakening, you guys in Bermuda might get away with another kite-flying sort of day. I'm working on that as a plan - I got until about Sunday. ;-)
He's weakening slowly at the moment because that dry air that I've mentioned before managed to creep in (sneaky!). We'll see if it'll keep him in check. Wind shear is not too strong, and water temperatures are still around 29 deg C with 26.5 deg C water in the upper 75-100m. So it's dry air or 'nowt' (a fine northern English colloquial term) that'll keep his intensity down.
Hurricane Julia:
Yeah, so here we start to really disagree. I've been pretty flabbergasted all day today as the NHC persisted in calling Julia a Cat 4 storm. As I suspected yesterday, she was stronger than the NHC had her but I didn't think they'd bump her up to a Cat 4!! Especially as she's the weakest, most pathetic looking cat 4 I've ever seen. I'd go with a cat 3 now, but earlier today I was more inclined towards a strong cat 2. I know she's the farthest east a cat 4 storm has ever been detected, but I am not convinced she ever got to that stage and I don't think I'm the only one who thinks this. But I saved my evidence during the day to make my case in the future if I have to. I completely disagree with the NHC on this one (in case you hadn't figured that out by now ;-)). My evidence includes:
1. She's over sea surface water temperatures of 27 deg C. Warm enough for a storm, but not particularly high.
2. Sub-surface waters of 26.5 deg C only extend down to in the upper 50-75m.
3. Actual tropical cyclone circulation (vorticity) structure is only in the lowest half of the troposphere. Above that, she's merged with a large front/trough thingy (technical term ;-) ) which is adding to her vorticity, but not in a tropical way.
4. There was an eye, but it's not been clearly defined at all in the visible satellite imagery, which it always is in a cat 4 storm - it's quite cloudy, and at some times it looks like there wasn't really one at all!
5. There is some wind shear - and you can see the impact of that in satellite images as clouds stream off to the northeast from the storm.
6. They are using estimated winds (135mph) and central pressure (950mb) based on satellite measurements, which are not 100% accurate.
7. This is the farthest east a cat 4 has been detected - surely something like that should have set off alarm bells and warranted further investigation of all these factors?
So, having ranted about this all day to anyone who would listen (i.e. my poor colleagues - I'm sure they have ear plugs by now), I've been trying to work out why they think (and continue to think) she's a cat 4 when ALL signs indicate otherwise. All except their estimated winds - and I'm not privvy to that information but maybe there's a glitch in that system or something? I don't know.
She's currently at 18.7N, 32.7W (officially they have her at 18.2N, 32.7W, but I think her center is a bit farther north) and is officially moving NW at 15mph. I think she's moving just east of the forcast center of cone track, but still in a general NW-NNW direction.
Tropical Storm Karl:
He made landfall in the morning (Mexico local time) in the Yucatan, just north of Belize. That warm water I mentioned yesterday did help him to intensify somewhat, and officially he had 65mph winds at landfall, making him a strong Tropical Storm (range: 39-73mph). Guess what... yeah, I disagree. ;-) Sigh. I think he was definitely a weak cat 1 storm at landfall. The convection was really strong, the vorticity signature was strong in the lowest half of the troposphere and had started to pick up in the upper troposphere (a sign he was a hurricane), and there was an eye!! The eye was just visible before landfall on the satellite images, but also on the radar from Belize. However, they kept him as a TS. I think the underestimation of his intensity is because the NHC didn't account for the really deep warm water he was crossing, they only considered the sea surface temperature (at least I didn't see any indication that they were considering the impact the sub-surface water would have). Luckily he was pretty close to land, otherwise he would have grown quite a lot more.
He's still a TS, located at 18.8N, 88.7W and moving W at 14mph. His winds have dropped to 55mph as expected because he's over land. Pressure is 994mb. He's crossing the Yucatan but still has a lot of convection - thunderstorms galore! Fortunately landfall was in a sparsly populated area. The forecast track takes him out into the southern Gulf tomorrow, where he is forecast to intensify to a hurricane before making landfall in Mexico (again). I think he's going to follow the southern edge of the cone, so he won't be over water as much as the track currently suggests. Whether he makes hurricane strength (again in my humble opinion) depends on how long he stays over water. The vorticity in the lowest half of the troposphere remains strong for now.
KF told me that wunderground was showing Karl surviving into the Pacific. I'm not convinced that will happen. He's going to be a remanent low before he gets that far.
That's all I have today. Sorry it's such a long entry... and I'm so disagreeable! Maybe some ice cream will help. ;-)
We'll see what excitement tomorrow brings! Fun fun!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
I know the NHC have the most up-to-date and bestest information, and they do an amazing job given the stresses and strains of issuing public forecasts of such magnitude, but today I'm afraid I have to disagree with them on the grounds of umm... er... on the grounds of er... well, just because. And so I do a thorough job of this, I disagree with them on all three Atlantic storms out there today.
Hurricane Igor:
Overnight Igor had 'estimated' winds of 155mph. You might recognize this number. It's the threshold between a Cat 4 and Cat 5 storm. A Cat 5 has winds of 156 mph or higher. The NHC kept him as a Cat 4, but I think for a few hours there he was a cat 5. 1mph in a 155mph storm is well within the error margins and his vorticity was extraordinarily strong. I believe they are reticent to call a storm a cat 5 if they don't have a plane that flies through to provide them in situ (latin for 'in the place') observations ... which might partly explain why cat 5's rarely form outside the recon flight area. Funny coincidence that, don't you think?
Anyway, he's officially been a cat 4 (range: 131-155 mph) all day today. However he has been weakening for the past few hours and personally I'd say that now he is a strong cat 3 (range: 111-130mph) because the eye is no longer clear, but the NHC are being cautious and keeping him as a weak cat 4 with estimated winds of 135mph and a central pressure of 942mb. He's moving WNW at 8mph, and is currently centered at 19.9N, 55.1W (I think he's moving NW, but that's just me). He's still about 1055 miles southeast of Bermuda, with hurricane force winds found up to 45 miles from the centre, and tropical storm force winds out to 225 miles.
He is moving slightly to the east of the center of cone track, which will take him east of Bermuda. If that trend continues and he carries on weakening, you guys in Bermuda might get away with another kite-flying sort of day. I'm working on that as a plan - I got until about Sunday. ;-)
He's weakening slowly at the moment because that dry air that I've mentioned before managed to creep in (sneaky!). We'll see if it'll keep him in check. Wind shear is not too strong, and water temperatures are still around 29 deg C with 26.5 deg C water in the upper 75-100m. So it's dry air or 'nowt' (a fine northern English colloquial term) that'll keep his intensity down.
Hurricane Julia:
Yeah, so here we start to really disagree. I've been pretty flabbergasted all day today as the NHC persisted in calling Julia a Cat 4 storm. As I suspected yesterday, she was stronger than the NHC had her but I didn't think they'd bump her up to a Cat 4!! Especially as she's the weakest, most pathetic looking cat 4 I've ever seen. I'd go with a cat 3 now, but earlier today I was more inclined towards a strong cat 2. I know she's the farthest east a cat 4 storm has ever been detected, but I am not convinced she ever got to that stage and I don't think I'm the only one who thinks this. But I saved my evidence during the day to make my case in the future if I have to. I completely disagree with the NHC on this one (in case you hadn't figured that out by now ;-)). My evidence includes:
1. She's over sea surface water temperatures of 27 deg C. Warm enough for a storm, but not particularly high.
2. Sub-surface waters of 26.5 deg C only extend down to in the upper 50-75m.
3. Actual tropical cyclone circulation (vorticity) structure is only in the lowest half of the troposphere. Above that, she's merged with a large front/trough thingy (technical term ;-) ) which is adding to her vorticity, but not in a tropical way.
4. There was an eye, but it's not been clearly defined at all in the visible satellite imagery, which it always is in a cat 4 storm - it's quite cloudy, and at some times it looks like there wasn't really one at all!
5. There is some wind shear - and you can see the impact of that in satellite images as clouds stream off to the northeast from the storm.
6. They are using estimated winds (135mph) and central pressure (950mb) based on satellite measurements, which are not 100% accurate.
7. This is the farthest east a cat 4 has been detected - surely something like that should have set off alarm bells and warranted further investigation of all these factors?
So, having ranted about this all day to anyone who would listen (i.e. my poor colleagues - I'm sure they have ear plugs by now), I've been trying to work out why they think (and continue to think) she's a cat 4 when ALL signs indicate otherwise. All except their estimated winds - and I'm not privvy to that information but maybe there's a glitch in that system or something? I don't know.
She's currently at 18.7N, 32.7W (officially they have her at 18.2N, 32.7W, but I think her center is a bit farther north) and is officially moving NW at 15mph. I think she's moving just east of the forcast center of cone track, but still in a general NW-NNW direction.
Tropical Storm Karl:
He made landfall in the morning (Mexico local time) in the Yucatan, just north of Belize. That warm water I mentioned yesterday did help him to intensify somewhat, and officially he had 65mph winds at landfall, making him a strong Tropical Storm (range: 39-73mph). Guess what... yeah, I disagree. ;-) Sigh. I think he was definitely a weak cat 1 storm at landfall. The convection was really strong, the vorticity signature was strong in the lowest half of the troposphere and had started to pick up in the upper troposphere (a sign he was a hurricane), and there was an eye!! The eye was just visible before landfall on the satellite images, but also on the radar from Belize. However, they kept him as a TS. I think the underestimation of his intensity is because the NHC didn't account for the really deep warm water he was crossing, they only considered the sea surface temperature (at least I didn't see any indication that they were considering the impact the sub-surface water would have). Luckily he was pretty close to land, otherwise he would have grown quite a lot more.
He's still a TS, located at 18.8N, 88.7W and moving W at 14mph. His winds have dropped to 55mph as expected because he's over land. Pressure is 994mb. He's crossing the Yucatan but still has a lot of convection - thunderstorms galore! Fortunately landfall was in a sparsly populated area. The forecast track takes him out into the southern Gulf tomorrow, where he is forecast to intensify to a hurricane before making landfall in Mexico (again). I think he's going to follow the southern edge of the cone, so he won't be over water as much as the track currently suggests. Whether he makes hurricane strength (again in my humble opinion) depends on how long he stays over water. The vorticity in the lowest half of the troposphere remains strong for now.
KF told me that wunderground was showing Karl surviving into the Pacific. I'm not convinced that will happen. He's going to be a remanent low before he gets that far.
That's all I have today. Sorry it's such a long entry... and I'm so disagreeable! Maybe some ice cream will help. ;-)
We'll see what excitement tomorrow brings! Fun fun!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Tuesday, September 14, 2010
Hurricane Igor, Hurricane Julia, and Tropical Storm Karl: September 14, Update A
Three named systems at the same time! My my, aren't we going up in the world? ;-)
Hurricane Igor:
Igor took a little rest earlier today and dropped down to a weak cat 4, with light breezy winds of only 135mph (!). It was a well-earned break because he's been working quite a lot lately, poor fellow. But clearly he wasn't going to sit around doing so little for long because his vorticity is WAY too strong throughout the entire troposphere (the lowest section of our atmosphere which, in the vicinity of Igor, goes up to a height of about 10-12km above the earth's surface). Officially he's now got estimated winds of 145mph so he's a mid-sized cat 4 (range: 131-155mph) but I think he's going to get stronger. Central pressure is estimated to be 933mb. I will not be surprised if he becomes the first official cat 5 of the season - as you know, I thought he was a cat 5 briefly yesterday and he might get there again.
He's currently located at 18.9N, 53.2W, and is officially moving WNW at a slow 8mph. At least he crossed that 18N line, so he's moving in that general direction and away from the northern Leeward Islands. But it means he's moving towards Bermuda instead. One or two of you may have noticed that the center of the cone goes directly over the little itsy bitsy island of Bermuda. He's forecast to get there on Sunday afternoon as a major hurricane (probably a cat 4). Now, whether it's a direct hit on Bermuda or not, he's strong enough and big enough to cause some problems there. For you Bermudians, make sure you've got your supplies ready: plenty of rum, water, wine, rum (I figured that would be cheapest thing out there), ice cream, batteries, rum, a book or two to read etc. You know... the usual stuff. Oh, and a raincoat too. Just in case. ;-) Seriously, I know you have gone through this sort of thing before so you know the drill. The chances are he won't pay a direct visit anyway, but will be swing by on one side. There is also a possibility that he will decrease in intensity before he gets to you because you are days away yet. Wouldn't that be nice?
Convection continues to remain really strong of course, with associated tornadoes and thunderstorms. He still has dry air ahead of him that is trying, somewhat unsuccessfully, to get into the system. Sea surface temperatures are around 29 deg C, with 26.5 deg C in the upper 75-100m. There is actually a bit of wind shear to his west. It's not big compared to the storm, but it's enough to make a small dent and may keep him as a cat 4 for a while longer - at least overnight and into tomorrow. It's difficult for me to assess how long this shear will last.
Hurricane Julia:
She's now officially a mid-size cat 1 storm with estimated winds of 85 mph (range: 74-95mph) and a central pressure of 982 mb. Her center is at about 16.7N, 30.2W and she's moving WNW at 9mph. Although she has circulation throughout the troposphere and some strong convective activity, she is experiencing wind shear which is keeping her from intensifying too quickly and is keeping the bulk of the convection to the east and south of the center of circulation. You can see the impact of wind shear in satellite images as well because there's a long stream of convection spreading away from her to the northeast. Water temperatures are around 27-28 deg C. I think she's a little stronger than the official intensity, maybe a strong cat 1. At the moment I agree with the NHC on her track forecast. She will move in a more WNW/NWestward direction for the next day at least, and will most likely remain in the Atlantic instead of crossing it, like Igor.
Tropical Storm Karl:
He's formerly my Caribbean Blob, and before that he was a Blobette. It's all so confusing sometimes! ;-)
Karl went straight from an area of invest to a weak Tropical Storm with winds of 40mph (TS range: 39-73mph) and a central pressure of 1001mb. A plane was sent to investigate this so these are actual values not estimates. His center is at 18.3N, 84.2W.
The good thing about this baby is that he decided to develop in the northwestern Caribbean and is heading WNW at 15mph, towards the Yucatan Peninsula. This is good because he's already close to land, so hopefully he won't become all bulked up before landfall. The bad thing about this baby is that he decided to develop in the northwestern Caribbean, which has the deepest warm water anywhere in the Atlantic/Caribbean/Gulf of Mexico region. The surface water temperatures are 29-30 deg C, but waters warmer than 26.5 deg C can be found as deep as 150-175m! So, no matter how much churning of the water he does, he'll still have warm water to feed from. I think that the land will be the greater of the two influences, so he shouldn't get too strong before landfall.
Circulation (Vorticity) is good in the lowest half of the troposphere - it's slightly stronger than it was yesterday. Nothing going on in the upper levels of the troposphere. This means he's not anywhere near hurricane strength. We can see this also in the satellite imagery because the convection is not very well organized.
That's it for today.
I think I'll take a nap now, but will be back tomorrow. Lots to see and do. It's all shiney. ;-)
Adieu,
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Hurricane Igor:
Igor took a little rest earlier today and dropped down to a weak cat 4, with light breezy winds of only 135mph (!). It was a well-earned break because he's been working quite a lot lately, poor fellow. But clearly he wasn't going to sit around doing so little for long because his vorticity is WAY too strong throughout the entire troposphere (the lowest section of our atmosphere which, in the vicinity of Igor, goes up to a height of about 10-12km above the earth's surface). Officially he's now got estimated winds of 145mph so he's a mid-sized cat 4 (range: 131-155mph) but I think he's going to get stronger. Central pressure is estimated to be 933mb. I will not be surprised if he becomes the first official cat 5 of the season - as you know, I thought he was a cat 5 briefly yesterday and he might get there again.
He's currently located at 18.9N, 53.2W, and is officially moving WNW at a slow 8mph. At least he crossed that 18N line, so he's moving in that general direction and away from the northern Leeward Islands. But it means he's moving towards Bermuda instead. One or two of you may have noticed that the center of the cone goes directly over the little itsy bitsy island of Bermuda. He's forecast to get there on Sunday afternoon as a major hurricane (probably a cat 4). Now, whether it's a direct hit on Bermuda or not, he's strong enough and big enough to cause some problems there. For you Bermudians, make sure you've got your supplies ready: plenty of rum, water, wine, rum (I figured that would be cheapest thing out there), ice cream, batteries, rum, a book or two to read etc. You know... the usual stuff. Oh, and a raincoat too. Just in case. ;-) Seriously, I know you have gone through this sort of thing before so you know the drill. The chances are he won't pay a direct visit anyway, but will be swing by on one side. There is also a possibility that he will decrease in intensity before he gets to you because you are days away yet. Wouldn't that be nice?
Convection continues to remain really strong of course, with associated tornadoes and thunderstorms. He still has dry air ahead of him that is trying, somewhat unsuccessfully, to get into the system. Sea surface temperatures are around 29 deg C, with 26.5 deg C in the upper 75-100m. There is actually a bit of wind shear to his west. It's not big compared to the storm, but it's enough to make a small dent and may keep him as a cat 4 for a while longer - at least overnight and into tomorrow. It's difficult for me to assess how long this shear will last.
Hurricane Julia:
She's now officially a mid-size cat 1 storm with estimated winds of 85 mph (range: 74-95mph) and a central pressure of 982 mb. Her center is at about 16.7N, 30.2W and she's moving WNW at 9mph. Although she has circulation throughout the troposphere and some strong convective activity, she is experiencing wind shear which is keeping her from intensifying too quickly and is keeping the bulk of the convection to the east and south of the center of circulation. You can see the impact of wind shear in satellite images as well because there's a long stream of convection spreading away from her to the northeast. Water temperatures are around 27-28 deg C. I think she's a little stronger than the official intensity, maybe a strong cat 1. At the moment I agree with the NHC on her track forecast. She will move in a more WNW/NWestward direction for the next day at least, and will most likely remain in the Atlantic instead of crossing it, like Igor.
Tropical Storm Karl:
He's formerly my Caribbean Blob, and before that he was a Blobette. It's all so confusing sometimes! ;-)
Karl went straight from an area of invest to a weak Tropical Storm with winds of 40mph (TS range: 39-73mph) and a central pressure of 1001mb. A plane was sent to investigate this so these are actual values not estimates. His center is at 18.3N, 84.2W.
The good thing about this baby is that he decided to develop in the northwestern Caribbean and is heading WNW at 15mph, towards the Yucatan Peninsula. This is good because he's already close to land, so hopefully he won't become all bulked up before landfall. The bad thing about this baby is that he decided to develop in the northwestern Caribbean, which has the deepest warm water anywhere in the Atlantic/Caribbean/Gulf of Mexico region. The surface water temperatures are 29-30 deg C, but waters warmer than 26.5 deg C can be found as deep as 150-175m! So, no matter how much churning of the water he does, he'll still have warm water to feed from. I think that the land will be the greater of the two influences, so he shouldn't get too strong before landfall.
Circulation (Vorticity) is good in the lowest half of the troposphere - it's slightly stronger than it was yesterday. Nothing going on in the upper levels of the troposphere. This means he's not anywhere near hurricane strength. We can see this also in the satellite imagery because the convection is not very well organized.
That's it for today.
I think I'll take a nap now, but will be back tomorrow. Lots to see and do. It's all shiney. ;-)
Adieu,
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Monday, September 13, 2010
Hurricane Igor, Tropical Storm Julia, and the Caribbean Blob: September 13, Update A
This week is the statistical peak of the hurricane season... it's all downhill from here and then it'll be hibernation time. Yay! ;-)
Hurricane Igor:
I must say, Igor is a very handsome looking storm! His mum (Mother Nature) must be proud. He's been holding pretty steady all day today as a very strong category 4 storm with winds of 150mph (cat 4 range: 131-155mph) and a central pressure of 933mb. He has also continued to head west and has slowed down a bit to 10mph. The center of the storm is at 17.7N, 50.5W but hurricane force winds (greater than 73mph) extend out 50 miles from the center and tropical force winds (greater than 39 mph) can be found upto 195 miles from the center.
Intensity: "The Force is Strong with this one" (Star Wars). ;-) It looks like his vorticity has improved throughout the troposphere so I wouldn't be overly surprised if he's actually a cat 5 storm (cat 5 winds >155mph), but if the NHC want to keep his winds officially at 150mph that's fine. At those velocities, what's 5mph between friends, hey? Wind shear is low and looks like it will remain low for the next day at least, so that won't hinder him. Convection is, of course, strong. Sea surface temperatures are a warm 29 deg C with waters warmer than 26.5 deg C in the upper 75m (and he's heading towards areas where the warm water is in the upper 100m). There is some dry air ahead of him and to the north but I don't think it's enough to do him much harm anytime soon. I think I'd have to agree with the NHC at the moment and say he's going to remain a major hurricane for the next day or two at least.
Track: Hmmm. I'm not overly pleased that he's still moving westward. The forecast track has been slowly inching to the west, but they still say he's going to turn to WNW and then NW tonight. He is following the southern edge of a high pressure (science snippet: in the northern hemisphere things move clockwise around a high pressure system). The models (with a couple of exceptions) are forecasting that the high pressure will erode and be replaced by a low pressure, which will allow him to move NW (clockwise) around what's left of the high pressure. This is forecast to occur any second now and I think he might actually be doing that. Either that or he's having a wobble. We won't know for a few hours (by which time I'll be asleep) so tomorrow morning let's see if he's crossed 18N. Of course, the farther west he travels, the closer he gets to the northern Leeward Islands of the Caribbean. And if he turn WNW and then NW, he's heading towards the Bermuda region. Sigh.
Tropical Storm Julia:
My Atlantic Blob turned into a Julia. ;-) She's currently a weak-to-mid-sized Tropical Storm with winds of 50mph (range: 39-73mph) and an estimated central pressure of 1000mb. She's too disorganized for me to see her center so I'll go with the official NHC location at 15.3N, 27.5W. She is moving WNW at 14mph - following in her big brother's footsteps. Water temperatures are 27-28 deg C, so warm enough to keep her going (tropical storms need sea surface temperatures warmer than 26.5 deg C). Her vorticity is really quite strong for this size Tropical Storm. I think she might be a bit stronger than the official forecast (but I don't think she's a hurricane).
Caribbean Blob:
I know I wasn't going to mention this blob until it got enough signatures to petition to become an official Tropical Depression, but I thought it worth mentioning that the vorticity (circulation) has improved during the day and is stronger in the lower half of the troposphere now. The convection still remains a mess, but Jamaica and parts of Cuba got a good shower or 10 today. It's moving WNW at 20mph. If it can pull itself together (circulation and convection), there's a chance it will develop further.
That's all for today.
Ciao!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Hurricane Igor:
I must say, Igor is a very handsome looking storm! His mum (Mother Nature) must be proud. He's been holding pretty steady all day today as a very strong category 4 storm with winds of 150mph (cat 4 range: 131-155mph) and a central pressure of 933mb. He has also continued to head west and has slowed down a bit to 10mph. The center of the storm is at 17.7N, 50.5W but hurricane force winds (greater than 73mph) extend out 50 miles from the center and tropical force winds (greater than 39 mph) can be found upto 195 miles from the center.
Intensity: "The Force is Strong with this one" (Star Wars). ;-) It looks like his vorticity has improved throughout the troposphere so I wouldn't be overly surprised if he's actually a cat 5 storm (cat 5 winds >155mph), but if the NHC want to keep his winds officially at 150mph that's fine. At those velocities, what's 5mph between friends, hey? Wind shear is low and looks like it will remain low for the next day at least, so that won't hinder him. Convection is, of course, strong. Sea surface temperatures are a warm 29 deg C with waters warmer than 26.5 deg C in the upper 75m (and he's heading towards areas where the warm water is in the upper 100m). There is some dry air ahead of him and to the north but I don't think it's enough to do him much harm anytime soon. I think I'd have to agree with the NHC at the moment and say he's going to remain a major hurricane for the next day or two at least.
Track: Hmmm. I'm not overly pleased that he's still moving westward. The forecast track has been slowly inching to the west, but they still say he's going to turn to WNW and then NW tonight. He is following the southern edge of a high pressure (science snippet: in the northern hemisphere things move clockwise around a high pressure system). The models (with a couple of exceptions) are forecasting that the high pressure will erode and be replaced by a low pressure, which will allow him to move NW (clockwise) around what's left of the high pressure. This is forecast to occur any second now and I think he might actually be doing that. Either that or he's having a wobble. We won't know for a few hours (by which time I'll be asleep) so tomorrow morning let's see if he's crossed 18N. Of course, the farther west he travels, the closer he gets to the northern Leeward Islands of the Caribbean. And if he turn WNW and then NW, he's heading towards the Bermuda region. Sigh.
Tropical Storm Julia:
My Atlantic Blob turned into a Julia. ;-) She's currently a weak-to-mid-sized Tropical Storm with winds of 50mph (range: 39-73mph) and an estimated central pressure of 1000mb. She's too disorganized for me to see her center so I'll go with the official NHC location at 15.3N, 27.5W. She is moving WNW at 14mph - following in her big brother's footsteps. Water temperatures are 27-28 deg C, so warm enough to keep her going (tropical storms need sea surface temperatures warmer than 26.5 deg C). Her vorticity is really quite strong for this size Tropical Storm. I think she might be a bit stronger than the official forecast (but I don't think she's a hurricane).
Caribbean Blob:
I know I wasn't going to mention this blob until it got enough signatures to petition to become an official Tropical Depression, but I thought it worth mentioning that the vorticity (circulation) has improved during the day and is stronger in the lower half of the troposphere now. The convection still remains a mess, but Jamaica and parts of Cuba got a good shower or 10 today. It's moving WNW at 20mph. If it can pull itself together (circulation and convection), there's a chance it will develop further.
That's all for today.
Ciao!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Sunday, September 12, 2010
Hurricane Igor, Tropical Depression 12, and the Caribbean Blob(ette): September 12, Update A
Great googliemooglies! and Crikey too! I've just looked at the Atlantic situation. Double crikey! I know I said I thought they had underestimated the intensity of Igor by "quite a bit", but boy did he grow up in a rush!
Hurricane Igor:
A cat 4!! when did that happen? Hmm... looking through the storm archives I see that they had him as a cat 2 and then upgraded him to a cat 4 a mere 6 hours later. Hmm. I'm not convinced. I suspect he's been a bit underestimated in terms of the intensity, but I've been away from a computer since yesterday so that's just my guess based on my reading of the storm versus the advisories issued at that time. Anyway, I think they have a better handle on the intensity now. They get my seal of approval about that.
So, Igor. Cat 4, hey? He has winds of 140 mph and a central pressure of 942mb. Those winds make him a mid-sized cat 4 (range: 131-155mph). He's still moving west at 14mph and is a good looking storm with a very clear and large eye centered at 17.7N, 46.9W. I don't see anything in the vorticity that suggests he will diminsh any time soon. Wind shear doesn't appear to be strong either. At the moment it looks like he will remain on a westward track. There is a low pressure from the north that might allow him to carve a path to the WNW and then NW before he gets to the northern Caribbean area. That turn, if its going to happen, should occur in the next 24 hours, so that's something to watch for.
Tropical Depression 12:
Goodness me! The NHC have finally decided to label blobs and blobettes (or invests as they call them) as Tropical Depressions again instead of going directly to a named Tropical Storm. This was formerly the Atlantic Blob that just came off the coast of Africa yesterday (or was it the day before?). It's still waaay out there to the east. It has very good vorticity in the lowest half of the troposphere now, but nothing above the mid-levels. It also has some convection, but not much from what I can see. It's a little too far east for me to see it clearly yet. More on this tomorrow if it develops further.
Caribbean Blob(ette):
Formerly the Caribbean blobette, but it looks like it was beaten to the Tropical Depression goal post by the far eastern Atlantic Blob. The vorticity has decreased in this system since yesterday, but the convection is still on-going and is bringing a lot of rain to Haiti and the Dominican Republic. It's still moving west across the Caribbean, but mostly as a blob of thundery weather. No more on this unless it develops into a TD or TS!
That's it for today! I'll be more awake tomorrow (the weekend is over, I suppose I have to be! ;-) ).
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Hurricane Igor:
A cat 4!! when did that happen? Hmm... looking through the storm archives I see that they had him as a cat 2 and then upgraded him to a cat 4 a mere 6 hours later. Hmm. I'm not convinced. I suspect he's been a bit underestimated in terms of the intensity, but I've been away from a computer since yesterday so that's just my guess based on my reading of the storm versus the advisories issued at that time. Anyway, I think they have a better handle on the intensity now. They get my seal of approval about that.
So, Igor. Cat 4, hey? He has winds of 140 mph and a central pressure of 942mb. Those winds make him a mid-sized cat 4 (range: 131-155mph). He's still moving west at 14mph and is a good looking storm with a very clear and large eye centered at 17.7N, 46.9W. I don't see anything in the vorticity that suggests he will diminsh any time soon. Wind shear doesn't appear to be strong either. At the moment it looks like he will remain on a westward track. There is a low pressure from the north that might allow him to carve a path to the WNW and then NW before he gets to the northern Caribbean area. That turn, if its going to happen, should occur in the next 24 hours, so that's something to watch for.
Tropical Depression 12:
Goodness me! The NHC have finally decided to label blobs and blobettes (or invests as they call them) as Tropical Depressions again instead of going directly to a named Tropical Storm. This was formerly the Atlantic Blob that just came off the coast of Africa yesterday (or was it the day before?). It's still waaay out there to the east. It has very good vorticity in the lowest half of the troposphere now, but nothing above the mid-levels. It also has some convection, but not much from what I can see. It's a little too far east for me to see it clearly yet. More on this tomorrow if it develops further.
Caribbean Blob(ette):
Formerly the Caribbean blobette, but it looks like it was beaten to the Tropical Depression goal post by the far eastern Atlantic Blob. The vorticity has decreased in this system since yesterday, but the convection is still on-going and is bringing a lot of rain to Haiti and the Dominican Republic. It's still moving west across the Caribbean, but mostly as a blob of thundery weather. No more on this unless it develops into a TD or TS!
That's it for today! I'll be more awake tomorrow (the weekend is over, I suppose I have to be! ;-) ).
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Saturday, September 11, 2010
Tropical Storm Igor, the Caribbean ex-Atlantic Blobette & yet another Atlantic Blob: September 11, Update A
I heard from John L. that the Klingon Opera was sold out so there's no point in going. Oh well. Maybe some other time then. ;-)
Tropical Storm Igor:
He's at 17.4N, 41.2W, heading west(ish) at 18mph. Winds are officially up to 70mph and have been for a chunk of the day, with central pressure at 995mb. This makes him a strong Tropical Storm (range: 39-73mph). Continuing the theme from yesterday, I think the NHC again have him at a lower intensity than he is - by quite a bit. Satellite images show an eye forming, but even worse... his vorticity is now strong throughout the troposphere. I think he might be a mid-to-strong cat 1, and he has the potential to become a cat 2. The track is a little murky for me to get a handle on today, but maybe tomorrow I'll have a better idea. I'm sure folks in the northern Caribbean and Bermuda are prepared anyway.
Caribbean ex-Atlantic Blobette:
Potentially the next Tropical Storm, this blobette has improved in looks over the past couple of days. Both circulation (vorticity) and convection had increased during the day, although convection just went bye-bye over the past few hours. Vorticity is still only in the lower half of the troposphere, and it's not very strong. I think it's definitely a Tropical Depression, but won't get to Tropical Storm status unless convection picks up again. It's undergoing some wind shear from the south, so most of the convection earlier today looked like it was a little north of where the center should be. But this is not very organized as storms go, so it's a bit difficult to see where the center is. Maybe somewhere around 15N, 67W. Maybe. It's bringing (or had brought) some squally weather to the VIs, PR, and Hispaniola already. The NHC have it at 60% chance of tropical depression formation in the next couple of days. It's moving westward(ish).
Atlantic Blob:
Hot off the press... well, hot off the coast of Africa anyway. This one has some decent vorticity (circulation) in the lowest half of the troposphere and convection is slowly picking up. I'll mention it again when it develops further (probably tomorrow in that case! ;-)). Next name is Karl. The NHC have this at a 70% chance of development. Personally, I think it's a little weaker than the Caribbean blobette at the moment.
Hmmm... that 'if I ignore them, they will go away' philosophy doesn't seem to be working very well. I might just need to re-think that one. ;-)
Toodle pips!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Tropical Storm Igor:
He's at 17.4N, 41.2W, heading west(ish) at 18mph. Winds are officially up to 70mph and have been for a chunk of the day, with central pressure at 995mb. This makes him a strong Tropical Storm (range: 39-73mph). Continuing the theme from yesterday, I think the NHC again have him at a lower intensity than he is - by quite a bit. Satellite images show an eye forming, but even worse... his vorticity is now strong throughout the troposphere. I think he might be a mid-to-strong cat 1, and he has the potential to become a cat 2. The track is a little murky for me to get a handle on today, but maybe tomorrow I'll have a better idea. I'm sure folks in the northern Caribbean and Bermuda are prepared anyway.
Caribbean ex-Atlantic Blobette:
Potentially the next Tropical Storm, this blobette has improved in looks over the past couple of days. Both circulation (vorticity) and convection had increased during the day, although convection just went bye-bye over the past few hours. Vorticity is still only in the lower half of the troposphere, and it's not very strong. I think it's definitely a Tropical Depression, but won't get to Tropical Storm status unless convection picks up again. It's undergoing some wind shear from the south, so most of the convection earlier today looked like it was a little north of where the center should be. But this is not very organized as storms go, so it's a bit difficult to see where the center is. Maybe somewhere around 15N, 67W. Maybe. It's bringing (or had brought) some squally weather to the VIs, PR, and Hispaniola already. The NHC have it at 60% chance of tropical depression formation in the next couple of days. It's moving westward(ish).
Atlantic Blob:
Hot off the press... well, hot off the coast of Africa anyway. This one has some decent vorticity (circulation) in the lowest half of the troposphere and convection is slowly picking up. I'll mention it again when it develops further (probably tomorrow in that case! ;-)). Next name is Karl. The NHC have this at a 70% chance of development. Personally, I think it's a little weaker than the Caribbean blobette at the moment.
Hmmm... that 'if I ignore them, they will go away' philosophy doesn't seem to be working very well. I might just need to re-think that one. ;-)
Toodle pips!
J.
Blog archives at http://jyotikastorms.blogspot.com/
-------------------------------------------
DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.
-------------------------------------------
Subscribe to:
Posts (Atom)
Posts
