The Former Hurricane Joaquin: October 8, Update A

Time for a final update on the-storm-formerly-known-as-Hurricane-Joaquin. 

He's decided that the UK isn't worth visiting at this time of year after all... the weather is too bad. ;-) Instead, apparently he's heading back home for a bit of Spanish sunshine (where else would Joaquin be from? :-))...

Actually, he is pretty weak and barely has any circulation, and probably won't be much by the time he gets across the Atlantic. From the satellite images, it looks like it may be cloudy and slightly rainy all the way from southern England to Portugal over the next day or so.

And that's about it on Joaquin. Time for a break now methinks. Should there be another storm this season, the next name is Kate.

Ciao for now!
J.

Blogs archived at http://jyotikastorms.blogspot.com/
Twitter @JyovianStorm
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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 "run away, run away" (Monty Python), I'll let you know.

Hurricane Joaquin: October 6, Update A

Goodness me, Hurricane Joaquin is persistent, isn't he? He's still hanging in there as a Hurricane. He is actually over the Gulf Stream, so sea surface water temperatures are still higher than 26 deg C, even though he's at 39N, 56.9W (in case you hadn't noticed, that is definitely outside the tropics!). And he just went through a region of very low wind shear, which allowed him to maintain his structure. So now he's left Bermuda, where is he going? 

He is heading ENE at 23 mph towards... the UK! Da da daaah! 

Heading home for a nice cuppa tea and a jaffa cake perhaps? Or scones with clotted cream and jam. Yummy.  

He does have very good circulation in the lower and middle troposphere, and just a tad in the upper troposphere so I would classify him as a very weak cat 1 now (cat 1 range: 74-95mph), possibly with winds around 75mph (the NHC have his winds at 80 mph - I reckon that's close enough). 

He is heading into a region of higher shear, and the water temperatures will drop, so I do expect him to be a Tropical Storm sometime in the next 24 hours (in this, I agree with the NHC). You can see that he's already wilting - in fact, he's mostly blustery and the convection has already started to decrease quite a bit:

By the time he gets to the UK region, it should be a breezy sort of day with maybe a few drops of rain. Usual summertime weather really. ;-)

Time for ice cream and an episode of Poirot now I think.
Toodle pip,
J.

Blogs archived at http://jyotikastorms.blogspot.com/
Twitter @JyovianStorm
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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 "run away, run away" (Monty Python), I'll let you know.

Hurricane Joaquin: October 4, Update A

Hurricane Joaquin is passing to the west-northwest of Bermuda, however his outer bands did go over the island. Luckily for Bermuda, he was not as strong as he was over the Bahamas! 

He is currently at 32.6N, 65.9W, about 65 miles from Bermuda, heading NNE at 14mph. The satellite images show us that he is considerably weaker now, and continues to weaken:

The NHC still have him as a mid-sized cat 2 storm, with winds of 100mph, central pressure of 961 mb (cat 2 range: 96-110mph). I think this is an large over-estimate of his winds given his structure and convection and I think he's really a weak cat 1 storm now. 

Regarding rainfall, they say that Bermuda should expect 3-5 inches of rain overnight. Here's the radar from Bermuda showing the surface rainfall in mm/hour:

3-5 inches is about 76-127 mm of rainfall. From the radar, even if you got 4mm/hour (on average), that mean it would have to rain solidly at that rate for 19 - 31 hours (tonight!). Hmm. Isn't mathematics fun? That is a very very long night! I'd be interested to see if that is how much you get. By the way, you can find the radar loop for this at: http://www.weather.bm/tools/animateimages.asp?name=RADAR_250KM_SRI. 

Speaking of rainfall, I saw that South Carolina got a wallop and half of rain! Crickey! Here's the water vapor satellite imagery for the US:

You can see that the predominant source of rain was that front that spans from south to north over a number of states, with some (but not too much) of the moisture being pulled in from Joaquin. 

Between the US east coast (esp. S. Carolina) and France flooding, H. Joaquin, Typhoon Mujigae (hit China as a cat 1), TS Choi-Wan, TS Oho, its a bit of a busy day in the weather-world!  

Ooof, I think it's time for a Sunday evening G&T!
Toodles,
J.

Blogs archived at http://jyotikastorms.blogspot.com/
Twitter @JyovianStorm
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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 "run away, run away" (Monty Python), I'll let you know.

Hurricane Joaquin: October 3, Update A

The news today isn't so good, alas. The cargo ship is still missing, and as the Bahamas emerges into the 'sunlight', there are reports of loss of life and, as we expected, severe damage on a number of islands. And on top of that, tenacious Hurricane Joaquin decided to strengthen, which I have a lot to say about! 

He is currently at 27.3N, 69.6W, heading NE at a really rapid 17mph. The track has been shifted slightly to the east and at this rate, he is expected to pass close to/over Bermuda late tomorrow:

I would go with the NHC track from here on out, because as I said yesterday, I don't have the  best information on this. 

His winds are officially 145mph, central pressure is 937mb. This makes him a strong cat 4 storm (cat 4 range: 130-156mph). I would agree that he did reach cat 4 strength today because he has had a good looking and persistent eye. Here is what he looks like now:

I know the winds that the planes reported were around 150-155mph, but the convection is not been as strong or well formed (circular) as you would normally see in such a strong cat 4/borderline cat 5 storm. Also, the eye is not as clear as it was, indicating that he is probably around a cat 3 now, possibly a cat 2. So I don't agree with the official word as far as the intensity. However, as he is heading towards Bermuda, I would prepare according to the official intensity!

Regarding intensity... <Soapbox Alert!> Joaquin has been a classic example of how poor our collective knowledge of hurricanes and their intensity really is.

The NHC statement at 11am today was: "...SEVERE HURRICANE JOAQUIN WITH 130 MPH WINDS MOVES AWAY FROM THE BAHAMAS..."

Just one hour later, they issued a special statement: "...RECONNAISSANCE PLANE FINDS SEVERE HURRICANE JOAQUIN WITH 155 MPH WINDS..."

First, I also thought that Joaquin would gradually weaken, so I'm not surprised that they were on the same page. The wind shear is actually quite strong (around 30-40 knots - in fact, I think it is that wind shear that is probably stopping him from becoming a cat 5 right now!) and he is heading into a region of even stronger wind shear. His vorticity (circulation) has remained strong throughout the troposphere, and I think that turned out to be more important than wind shear in this case. Also, he is interacting with the front that brought rain to the east coast this week, which is complicating things. Luckily he had moved away from the islands before intensifying (the islands, although small, may have been enough to stop him from intensifying at that time). 

Second, the reason the NHC increased his wind speed so drastically after an hour is because they got data back from a hurricane hunter plane. In this day, why are they still depending on sending people in planes into a storm to gather the data they need to work out the intensity? Surely we can do better than this? This has been our method of gathering data from these storms for ~70 years -  since the 2nd World War! Surely it's time to rethink this and get continuous, good data? (by the way, if you have a few $100k lying around and are interested in figuring this out send me a note, I know exactly how I would go about sorting this out!)

Third, there is now of course the inevitable debate over computer models, tracks, and our ability to forecast weather. Three/four days ago, the NHC track had Joaquin clipping/hitting the US east coast, the best US model (that NOAA uses) - the GFS), was showing a track to the east of that, and the Europeans model (ECMWF) was showing a track that took him close to/over Bermuda. Here's a pretty good article from the New York Times on this: http://www.nytimes.com/2015/10/03/upshot/hurricane-joaquin-forecast-european-model-leads-pack-again.html. I agree with this, it isn't ultimately about 'how big is my computer', but rather 'how good is the observational data' and 'how good is the model'. The observations are used to set the stage for models, and then the models calculate what will happen in the future, based on what we know about the physics of the storms. Bad data in = bad data out. And incorrect physics (i.e. not understanding the system) = Incorrect forecast. In this case, both the US and European models are very good, so it therefore boils down to the good data in piece. 

<End Soapbox Alert!>

I'm a bit parched after all that... time for a cuppa tea and a jaffa cake or two. 

Stay safe Bermuda!!

Until tomorrow,

J.

Blogs archived at http://jyotikastorms.blogspot.com/
Twitter @JyovianStorm
-------------------------------
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 "run away, run away" (Monty Python), I'll let you know.

Hurricane Joaquin: October 2, Update A

The good news is that Joaquin is finally on the move! I can only imagine what it's been like to be living under a hurricane of any magnitude for about 3 days! From the early reports there are no signs of loss of life on the islands, although some of the smaller islands/central Bahamas have sustained a lot of structural damage. The search is on now for a large cargo ship with a crew of 33 on board (28 American and 5 Polish citizens), but of course the weather is still making that a bit tough. 

Joaquin is currently at around 24.7N, 74 W and is heading NE at nice 7mph. Although his official wind speed is 125mph (central pressure is 944mb), which makes him a strong cat 3 storm, I think he is weaker than this. He hasn't had a good clear eye for quite a few hours so I would place him as a cat 2 storm at the most. All indications are that he is definitely weaker, although he is still a large storm in area! The vorticity (circulation) has decreased in the upper troposphere - it is still good, so I would definitely say Joaquin was still a hurricane. The visible and infrared satellite images also show a weaker storm. The convection is elongated, and if you look at the latest infrared satellite loop you can see that the red area of really strong convection is breaking up...

This is because on his east side he is experiencing some stronger wind shear, and on the west side, there is dry air. His eye did also directly pass over one of the smaller islands today, which would have brought him down a peg or two. Sea surface temperatures are still in the 28-29 deg C, but as he moves northward, the depth at which water warmer than 26 deg C exists gets shallower (it is now around 75m as opposed to over 100m around the Bahamas). I expect him to continue to weaken as he moves north because he's moving into a region of stronger wind shear and cooler waters. 

Here's his latest official forecast track: 

I would agree with this for the next 24 hours, but I see some adjustments to this in his future. Unfortunately I don't have good enough data over the oceans at the moment to say whether this will shift to the east or west, but of course, you folks on Bermuda should be getting ready too (although he will be weaker). 

And in case you missed this a few days ago, here's one of the first picture of water on Mars (thanks to Keith L. for this one!)... 

(Yummy Mars, the edible planet! ;-)). 

Until tomorrow, 
J.

Blogs archived at http://jyotikastorms.blogspot.com/
Twitter @JyovianStorm
-------------------------------
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 "run away, run away" (Monty Python), I'll let you know.

Hurricane Joaquin and a Landmark Moment: October 1, Update A

What a topsy-turvey sort of day today turned out to be! I spent most of the day flying across the country (from DC to LA) and below me, The Good, The Ugly, And The Uglier was playing out! You have probably already heard about The Ugly (or The Uglier - the jury is still out) from Orgeon (something I will never understand!), but you may not have heard about The Good yet...  

... I have to take a moment to tell all of you wonderful amazing intelligent readers to grab a G&T, a wine, an ice cream, a cup of tea, some cheese, whatever you like that makes you happy, and partake! Today, because of YOU, the number of page views on my blog crossed the 100,000 level!! (Thanks to my husband for capturing the moment for me! :-))

Never did I imagine when I started this about 9 years ago that we would get to this point! And these numbers don't include the many years of having a separate list serve! For once, I may be a bit speechless (as evidenced by excessive use of exclamation marks)! (so I'll just have another sip of my G&T ;-)). 

Enough of that! Moving right along, and then we have The Uglier (I think, although we won't know until he leaves the Bahamas). Sigh. Hurricane Joaquin is a cat 3 storm, borderline cat 4 storm and is continuing to try and demolish the Bahamas - I have to say, it doesn't look too good for them. I'm not sure what will be left after he's done! The visible satellite image showed a clear and good looking eye during the day:

His current official wind speed is 130mph, central pressure is 935mb. This makes him barely a cat 4 storm (cat 4 range: 130-155mph). I missed most of today so I don't know if he got that strong, but I can say he was definitely a cat 3. It looks like he has diminished recently, and I don't see a clear eye anymore, so I would place him at the most as a cat 2 now, but I'm sure the NHC will decrease that slowly so he'll probably be downgraded to a cat 3. You can see that he's weakened from his infrared satellite imagery too:

His interaction with land is keeping him 'in check' - the little land that is the Bahamas, as well as the slightly larger land of Cuba and Hispaniola. 

The vorticity (circulation) remains very strong throughout the troposphere, which indicates that he is a well built storm. I haven't seen that decreasing yet, which means he will continue as a strong storm for now. 

As for his track, here's the latest... 

Oops, sorry, wrong file (thank Ai-Ning in North Carolina for that one!). You know it was only a matter of time before someone made this. Although to be more accurate, I think he's a hairier storm over the Bahamas than I think he will be to the north! 

The real track...

This shift to the east is a bit more realistic, although I still don't think we have a good handle on his track. We won't really until he clears the Bahama and starts to head north. He is currently at 22.9N, 74.6W, heading W at a measly 3 mph! I could probably walk faster than that! He is still pretty much stationary over the Bahamas, as expected. Ugh. 

If I were you on the east coast and Bermuda, I would be getting ready, just in case. The forecast has him on his northward trek late Friday/early Saturday, so we'll have a clearer idea by this time tomorrow. Hopefully.

That's about it. Oh, and before I sign off, to mark this landmark day in the life of this blog, and in case you are confused about hurricane intensity and what a cat 1 versus a cat 2 versus a cat 3 and so on looks like... here's a little pictorial clarification I received from Jen D. (also from North Carolina) today:

Cats... always popular on the internet! :-) 

Toodle Pip!!
J. 

Blogs archived at http://jyotikastorms.blogspot.com/
Twitter @JyovianStorm
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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 "run away, run away" (Monty Python), I'll let you know.

Hurricane Joaquin: October 1, Update A

The poor Bahamas are really getting a beating! Hurricane Joaquin continued to move southwards and he grew, and now the islands are under the truly worst part of the convection. The red/grey areas in the infrared satellite image show the areas of highest cloud tops and therefore the strongest thunderstorms, tornadoes etc.:

If you want a quick reminder of how to read these IR satellite images, look at the technical alert here!

He is officially currently at 23.4N, 73.7W, heading WSW at 5mph. This means he's barely moving, which of course makes it even worse for the Bahamas! Speaking of track, here's the latest from the NHC:

He'll start to move away from the Bahamas on Saturday. It is interesting that the cone of uncertainty is so broad, but that is because this storm has pretty much stalled, which adds another level of uncertainty (plus we are looking at 4-6 days out, which is always poorly forecast - I trust the 1-2 day forecast at the most!). If he had continued to move, we would have more certainty because he would have been swept into the Atlantic by the low pressure front that is moving through the US east coast (that's why you all had so much rain this week). But because he stalled, that front is moving through and not really interacting with him. The uncertain track is in trying to figure out how much the front will impact Joaquin. You can see that in the low tropospheric level vorticity map - the low is that streak of yellow/green along the US east coast:

I think he will stay off shore for most of the way up and by the time he gets up to the general New York area, he should be a bit weaker so hopefully the impact won't be that much (and he may even be quite far offshore by that time). HOWEVER, it's best to get ready (if you don't already have your supplies of water, ice cream, candles, and wine ;-)) and pay attention to your emergency managers as they have the most up-to-date local information. 

His winds are officially estimated to be 120mph (central pressure 942mb), which makes him a strong cat 3 storm (cat 3 range: 111-129mph). The upper levels of the troposphere also have a good signal, which means he is very strong. Here's the map from 200mb (the highest level of the troposphere):

I don't see a solid eye in Joaquin in the visible satellite imagery though, which indicates that he may not be quite that strong at the moment...

But, he has just emerged from the night and there is a hazy eye, so I would definitely place him as a cat 2 storm at least. 

Another travel day today. More tomorrow!
Ciao,
J.

Blogs archived at http://jyotikastorms.blogspot.com/
Twitter @JyovianStorm
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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 "run away, run away" (Monty Python), I'll let you know.

Hurricane Joaquin: September 30, Update A

Just time for a quick update. It's no surprise that TS Joaquin got stronger as he was already stronger than the official estimate I saw before I got on a plane yesterday. It looks likes the wind shear wasn't enough to keep him in place, and that vorticity signal I saw in the upper troposphere has also intensified which makes him a hurricane.

He is currently centered at 24.9N, 72.2W, moving SW at 6mph. Winds are 75mph, central pressure is 971mb. At 75mph, he is barely a cat 1 storm (range: 74-95mph), but I think this is still an underestimate, especially if that is his central pressure. That is quite low, which means that the winds will 'rush' in faster. The other indication that this is low is the vorticity (circulation) in the upper half of the troposphere, which is much stronger and better developed today than it was yesterday. Here's the 500mb level - which is the middle of the troposphere:

You can see a lovely red distinct splodge (technical term ;-)) at that level. Looking even higher, up to 200mb (about 10km above the earth's surface):

The 'red splodge' at those heights is now distinct from that larger red region to the northwest (a low pressure region), so it is really connected to this storm and not that system. This is what I would see with a hurricane. 

He is beginning to develop into a good looking storm with those lovely outflow bands, which you can begin to see in the visible imagery: 

I can't be sure that he had an eye overnight or not from this imagery. If he did, then his winds were closer to 90mph. I would place him as a storm with winds around 85mph at the moment. 

Fortunately the strong convection is not as spread out as the visible imagery would suggest, with those outer bands to the north being just clouds (blue in the infrared imagery):

The Bahamas are getting some rain, but the worst weather is offshore. Unfortunately, Joaquin will stay in that area for a while, so it will bring a lot of rain to the islands so they will have a rough few days. Also, the winds will be pushing water onto the northern sides of the islands, so expect storm surge! 

I'll try and pop back later today and check in on him.

Adieu,

J. 

Blogs archived at http://jyotikastorms.blogspot.com/
Twitter @JyovianStorm
-------------------------------
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 "run away, run away" (Monty Python), I'll let you know.

Tropical Storm Joaquin: September 29, Update A

Another travel day, another quick blog written from LAX airport. :-) Did you catch the water on Mars news yesterday? How exciting. And in today's news, a big day at XPRIZE (see the end of the post for that). But first... 

Tropical Storm Joaquin was named yesterday and is currently at 26.6N, 70.6W, heading W at a very sedate 5 mph. His winds are officially 40mph, and central pressure is 1006mb,which makes him a really weak storm (TS range: 39-73mph). I think this is a bit of an underestimate and he slightly stronger - he has exceedingly good circulation in the lower half of the troposphere, with a small vorticity (circulation) signal in the upper troposphere (because he is interacting with a low pressure system up there). I'd place him at 50-60mph at least! He is a decent looking Tropical Storm, as you can see in the visible satellite imagery:

He also has quite a lot of convective activity as you can see in the infrared satellite image - I hope the Turks and Caicos folks had their wellies dusted! 

The major thing keeping him in check is wind shear, which is around 20-30 knots. It looks like he may move into a region of stronger wind shear, so I don't think he'll get much stronger (at the moment anyway). I'll be back tomorrow. 

Meanwhile at XPRIZE: today (and tomorrow) is the launch of the Carbon XPRIZE! $20 million for a bright, innovative team who can turn CO2 into a valuable product... more details are here: carbon.xprize.org.

Ok, must run, but more from the east coast of the US! 
Toodles,
J. 

Blogs archived at http://jyotikastorms.blogspot.com/
Twitter @JyovianStorm
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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 "run away, run away" (Monty Python), I'll let you know.

Tropical Depression Ida, the Caribbean Blob, and the Atlantic Blobette: September 26, Update A

Just popping in to check on how Ida and her friends are doing in the Atlantic and Caribbean. I see that she's still trying her best to hang on, but is now a Tropical Depression. 

Officially her winds are 35mph, central pressure is 1006mb. She does still have a closed circulation in the lower half of the troposphere, but she is not as well developed in the middle and upper parts of the troposphere, so a Tropical Depression seems about right to me. You can see her location and the closed circulation in the visible satellite imagery:

She is centered at around 24.3N, 47.4W, and is heading WNW at 5mph. You can also see that her convection is off to the east of the center and is struggling to get a foothold (it's been on a pattern of getting stronger/weaker/stronger/weaker):

It's to one side because of wind shear of course, and it's a bit wimpy because there is a spectacular amount of dry air all around her, as you see in this lovely water vapor imagery of the Atlantic:

So even if the wind shear drops (which it is expected to do), the dry air will stop her from growing too much. In fact, I think this will be my last update on Ida (unless something unexpected happens - and really, how often does that happen? ;-)).

Now, a quick note about a Caribbean Blob and it's friend, the Atlantic Blobette. You can see them in the water vapor satellite image above. 

One is in the region of Nicaragua, with quite a lot of convection just off the coast there, in the western Caribbean. The reason for the strong convection is because the sea surface water is over 30 deg C (phew... definitely balmy!), and the upper 100 - 150m of the water column is warmer than 26 deg C. We always see a lot of convection in this area for this reason. There is some circulation in the lower half of the troposphere, but it is interacting with land which is inhibiting the development of this system. It does look like it will move over water though (it's moving very slowly north-eastward) and away from land, which will give it a chance to get a bit stronger.

The second one is just north of the Bahamas. This one doesn't have much convection at the moment but again, there is weak circulation in the lower parts of the troposphere. 

The next name up is Joaquin. 

I'll keep an eye on both of these and if they look like they are going to misbehave, I'll be back. 

Ciao for now!
J. 

Blogs archived at http://jyotikastorms.blogspot.com/
Twitter @JyovianStorm
-------------------------------
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 "run away, run away" (Monty Python), I'll let you know.

Tropical Storm Ida: September 22, Update A

Time for a quick update. 

Tropical Storm Ida is at 20.9N, 46.8W, and is drifting ESE at a whopping 2mph! (i.e. she's stationary). She's been hovering over the same place for a few hours and is actually showing signs of weakening now, and you can see that the circulation (vorticity) in the middle troposphere is no longer a well formed as it was yesterday:

No circular red blob anymore at the 500mb level. 

There are a couple of reasons for this but the primary one is that there is actually quite strong wind shear today, with the shear being around 20-40 knots from the northwest. Her official wind speed is currently 40mph (central pressure 1005mb). So, with such strong wind shear we would expect the convection to be 'pushed off' to one side of the center, and sure enough, it is trailing spectacularly off to the east: 

If you are paying attention (like Mitch R.), you may have noticed a swirly-gig to the west of Ida, between Puerto Rico and Bermuda. This was ordered especially for Steve B. who is sailing this week from PR to Bermuda. ;-) (sorry Steve!). It is even more spectacular in the water vapor satellite imagery:

Although this blob has some circulation, it is not very well organized as you can see from the 500mb vorticity map above and more importantly, there is absolutely no circulation in the lower troposphere:

So I wouldn't worry too much about this one. 

Alas, that's all I have time for today. I'll try and get back tomorrow, but if not, then the following day!

Toodle pip,
J.

Blogs archived at http://jyotikastorms.blogspot.com/
Twitter @JyovianStorm
-------------------------------
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 "run away, run away" (Monty Python), I'll let you know.

Tropical Storm Ida: September 21, Update A

Distressingly little time for sloth or idleness today, alas! TS Ida has slowed down, and is now officially at 21.7N, 49.5W, moving NNW at 5mph. It is a bit difficult to see her center at the moment because it's night time (obviously! ;-)), and also because she appears to be a a bit disheveled. I think the center may be slightly to the south and east of the official location.

The NHC did increase her wind speed today, but have brought it back down to a very weak 45mph (Tropical Storm range: 39-73mph). I continue to think this is a bit of an underestimate (British understatement strikes again). There are a few clues that lead me to believe she is stronger than they think:

1. The vorticity (circulation) is stronger in the lower half of the troposphere than it was yesterday. For example... 

Yesterday's 500mb vorticity field: 

Today's 500mb vorticity field: 

See how much better formed (rounder and redder) she is? You too can look at the evolution of the circulation if you go to the University of Wisconsin page - at the top left are buttons that allow you to move back in time in 3 hour increments. (By the way, if you have forgotten how to get to this page, check out the <Science Alert!> here).

2. They claim strong wind shear. The wind shear is somewhere between 10-20 knots. Her winds are 45mph, which translates to about 40 knots. If this is really her wind speed, this means she is experiencing wind shear that is half as strong as she is. That would be really strong relatively speaking and she should have fallen to bits already!  

3. Oh, and then there's the convective activity. Does this really look like a system that is barely eking a living as a Tropical Storm to you? 

 

And looking at her on the larger Atlantic stage:

Yes, ladies and gentlemen, that big red blob that could swallow most of Florida is, supposedly, a very very weak Tropical Storm. Really?

Huh. 

So, to sum up: I agree with the NHC that she's slowed down and her name is still Ida. 

Until tomorrow! 

J. 

Blogs archived at http://jyotikastorms.blogspot.com/
Twitter @JyovianStorm
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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 "run away, run away" (Monty Python), I'll let you know.