Friday, July 31, 2020

Hurricane Isaias: July 30, Update A

It's Thursday again, isn't it? Wasn't it just Thursday a couple of days ago? I never can get the hang of Thursdays... they are especially rocky when there's an earthquake (a good pun is it's own re-word by the way). ;-) 

Still, the two pieces of good news from today are that we (humans) have three missions on their way to Mars and, of equal importance of course, that we (the NHC and I) are finally in agreement over Hurricane Isaias!

They increased his intensity, which I fully agree with.... Isaias is now a fully-fledged hurricane. This makes a lot of sense given that there has been a vorticity (circulation) signal in his upper troposphere (sign of a hurricane!) since yesterday. It's still not perfectly round and contained, so a cat 1 seems reasonable - he's currently a weak cat 1 storm with winds of 80mph, central pressure of 995mb (cat 1 range: 74-95mph). You can see that he's got a lot of convection (rain, thunder, and I expect tornadoes in there somewhere) from the infrared satellite imagery:
There isn't a clear eye and the convection doesn't quite wrap around the center fully which aligns with winds around 80mph (and eye starts to appear somewhere around 90mph). 

He is still being impacted by wind shear, which we can see as the clouds stream off to the northeast. And he also still has dry and dusty air ahead of him, which is still keeping his convection in check. 

As for his track, he did turn to the NW overnight/during the day today and he did go over Hispaniola, which is as the NHC forecast. For the most part along the Greater Antilles he wasn't as much of a wind issue as a rain and thundery weather sort of storm. I heard things are ok on St. Thomas, apart from a propane gas explosion that blew up a yacht in a marina earlier in the week (just because this week was going to be slow). 

Once they had the center location, that track forecast improved dramatically. His center is now at 20.4N, 72.2W and he's heading NW at a more reasonable hurricane pace of 18mph. It is a little more straightforward from here on out, so I would agree with the NHC track: 

As he crosses the Turks & Caicos and Bahamas, I expect he will get a little stronger - most likely a mid-to-strong cat 1 (but no more than a weak cat 2). As I said, he has some dry and dusty air ahead of him as well as that wind shear. And if his center goes directly over one of those islands, it will help keep his intensity in check - even just a very little.

That track forecast is now better than any data I have, so I'll go with that. Keep an eye on the entire cone of course, not just the center. 

Also, just in case those of you in Florida haven't seen this yet - your Emergency Managers have been busy working with hotels across the state to set up shelters that allow for social distancing. The link takes you to a website/map with those places. The notice when you get to this site says that all decisions on using those shelters will be made by local emergency managers. 

I think that's almost all for this Thursday. I'm also keeping half an eye on the new Atlantic Blobette that's just come off the coast of Africa - currently around 12.5N, 20W. She has a 40% chance of developing in the next 48 hours. I'm not going to mention her unless she gets a little more robust. 

More tomorrow!
Toodles,
J. 

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 local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know. 
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Thursday, July 30, 2020

Tropical Storm Isaias: July 29, Update A

Tomorrow is a big day - the third launch to Mars in as many weeks (ish). It'll be NASA's turn with Perseverance. Ah, I still remember the first image from the Curiosity Rover... 
I was not overly surprised. ;-) 

So, they finally tossed this storm to the pterodactyls and took him from 'Potential' to 'IRL' (In Real Life). He's now finally achieved Tropical Storm Isaias (pronounced: ees-ah-EE-ahs) status. He is currently 'centered' at 15.8N, 76W, officially heading WNW at 20mph. 
They have consistently been moving his center south, which is why he didn't head to Puerto Rico, as they expected he would yesterday: 
Instead, in fact, his current center is directly south of Puerto Rico and quite far outside yesterday's Cone of Uncertainty - making this one of the worst track forecasts we've seen in a very long time (years). As I said, I think that's because they had his center too far north by at least 2 degrees latitude in the first place. 

However, for some reason they are still insisting that his track will head to Florida, which means that if he is to keep within his Cone of Uncertainty for today, he's going to have to move NW within the next few hours, not WNW. Clearly there is still some confusion on the track for this storm. From the NHC: 

"Since the cyclone is expected to move over Hispaniola on Thursday  some weakening is likely within the next 24 hours.... Also, a re-formation of the center to the north of Hispaniola may occur. 

The scatterometer data show that the center of the system is south of the previously estimated track, so there is a lot of uncertainty in the initial motion estimate of 285/17 kt." 

(285 is the degrees on a compass... where 270 deg is due W, so 285 is WNW). 

I'm not sure how the storm is expected to move over Hispaniola AND re-form to the north. Some form of Klein tunnel, perhaps? ;-)  

I'm still not convinced he's going to head NW - I think he'll stay a little more to the south and on the WNW track, but we'll know this in the next few hours. But I do think they finally have a relatively good general area for the center - so today I agree that 'x' marks the spot. 

As for the intensity... he is currently a relatively weak Tropical Storm with winds of 50mph, central pressure estimated to be 1004mb (Ts range: 39-73mph). He does have a few buckets of rain (with some thundery weather) that he's pouring over the islands - cleaning the cars, washing the Saharan Dust away...

Interestingly, his intensity is based on consistent winds in the Atlantic! Not in the Caribbean, near his center? From the NHC:

"The current intensity is estimated to be 45 kt, but these winds are currently occurring over the Atlantic waters well to the north and northeast of the center."

But there is no doubt he would be a fully fledged Tropical Storm and from the size of him, if there wasn't any Saharan Air Layer or wind shear keeping him in check, he would be a big boy! Here's the SAL image, which really brings home how large of an area his clouds actually cover:

I estimate from south to north, those clouds cover around 1400 miles! 

But what about his intensity? His vorticity (circulation) has been improving over the past couple of days. Officially, he is a weak TS, however there is now a vorticity signal (circulation) in the upper troposphere, which indicates that he is actually quite a bit stronger than the 50mph that they have him at. Another indication of strengthening is that we see some deep convection solidifying in the center from the satellite imagery - that's because he's over very warm water (warmer than 29 deg C) with the upper ~125m now warmer than 26 deg C. His center is also quite far from the dry, dusty Saharan Air Layer, so that isn't stopping the gooey marshmallow center from developing. 

So, the bouncy ball I'd like to leave you with is that today, for the first time, I agree with the NHC on the location of his center. I think he'll continue on a more WNW track for at least another day or so. If, in the next 12 hours, he doesn't move more sharply NW then he won't be moving over Hispaniola, but instead he'll intensify further as he stays over that deliciously warm water in the Caribbean.

Regardless, everyone should be ready anyway - I have my wine and cheese so I'm ready!

Until the 'morrow!
Ciao,
J. 

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 local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know. 
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Wednesday, July 29, 2020

'Potential Tropical Cyclone' Nine (The Atlantic Blob): July 28, Update A

Oh what?! No time for dilly-dallying today! What is this made up 'Potential Tropical Cyclone' Nine business?? Either it is a Tropical Depression (in which case, feel free to give it a number) OR it's a Tropical Storm with a name! This 'Potential' is a bit of a wishy-washy designation that's neither one nor t'other. 
 
Here's the story so far... this Atlantic Blob does NOT have a well-developed closed circulation as we expect to see in Tropical Storms, but  it clearly has some areas of strong convection which are here in the satellite imagery: 

The Lesser Antilles are currently getting quite a drenching with some thundery weather, but not much sustained winds and there isn't a clearly defined center of circulation. This is confirmed if we look at the vorticity map to see what the circulation actually is...in the lowest levels of the troposphere (850mb) it does not have the signature of a tropical storm because it is far too broad and not very circular (it's more like a lava lamp blob actually):

And the vorticity in the middle of the troposphere (at 500mb) shows there are two conjoined areas of circulation - also not a tropical storm signal: 
And there isn't any vorticity in the upper troposphere. So, all the vorticity data indicates that this is NOT a Tropical Storm or a Tropical Depression (because there isn't a single center of circulation). 

It has clearly been trying to develop since yesterday, but the SAL has done an excellent job of keeping it otherwise occupied. I think the reason it is still around and trying to become something is because the dry and dusty air is not near the 'center' - there is a really large band of humid area and clouds around wherever the center should be:
And it's that outer band of clouds to the north and west that are 'battling' the dusty SAL air. 

There is also some wind shear that is at play here which is also helping the SAL to keep it in check. We can see that in the satellite imagery (and the SAL image) with the clouds trailing to the northeast. But it is still producing heavy convection (rain, thunder etc) because it is over water that is 28-29 deg C at the surface of the ocean, with the upper ~100m being warmer than 26 deg C - that is enough to keep a storm well-fed and happy. 

I think by calling it a 'Potential Tropical Cyclone' they can issue warnings and a track, in case it makes a sudden move - which of course means they aren't sure how much it will develop. It is currently officially centered at 14.6N, 59.4W (even though they inferred a center), heading WNW at 25 mph (which, by the way, is super-fast for a Tropical Storm - usually less than 20mph). 
Winds are officially estimated to be 40mph (set just above the magic 39mph threshold which means it can be moved directly to a named Tropical Storm once it has a closed center of circulation), and central pressure is estimated to be 1007mb (which is about right for something that's a depression).

This is a tricky one with all of these complicated factors at play. But why stop here, let's add one more shall we?  The path it will take may take it directly over islands - which are a bit hilly. If the 'center' goes over land and it's a weak system it will get knocked down a notch. 

The story going forward... I think it may slow down very soon (they think it'll slow down in about 48 hours). If it slows down it will most likely intensify, given that the dusty air is quite far from the center and the water is rather toasty warm. However, I think they have put the center too far north - I think it may be closer to 12.5-13N, not 14.6N. So I am not 100% convinced of that track yet either. 

I'd get ready for a bit of a downpour in the VIs, Puerto Rico, and all along that track, but at the moment there is a lot of uncertainty in both the track and the intensity on this one.  

I'll be back tomorrow - maybe twice if I can. This is a very interesting one indeed!

Toodle pip!
J. 

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 local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know. 
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Tuesday, July 28, 2020

Tropical Storm Douglas and the Atlantic Blob: July 27, Update A

It's Monday, grab a glass of wine (which is not contingent upon it being a Monday of course ;-)) and have a seat.

Atlantic Blob
This blob's conversations with the Saharan Air Layer continue... his chances of developing in the next 48 hours have gone down another notch to 70%. He is trying to develop, as we can see with the bits of convection we see in the satellite imagery: 

Although he is over surface warm water with temperatures of 27 deg and he's about to move over warmer waters of 28 deg C (with the upper 75-100m warmer than 26 deg C), I'm not sure how much he will be able to get his act together because the atmosphere is working against him. First, it looks like he'll be having a few days of conversation with the dry dusty Saharan Air Layer (probably catching up on everything that's been going on in 2020 - could take a while!):

And second, wind shear will increase as he moves north and west. 

According to the NHC, he is currently somewhere around 13N, 48.5W and moving WNW at 15-20 mph. However, this location is very much a guess because the circulation is over such a broad area. There is some low level circulation in the lower half of the troposphere, but we can see from the lower tropospheric vorticity map that it is not very well developed at all and is spread out over a very large area indeed. 

The NHC think he will be bringing a few drops of rain and a bit of a breeze to the islands - the Leeward Islands on Wednesday, then on to the VIs and Puerto Rico on Wednesday night and into Thursday. Best to be ready if you are there, but he won't be too much of a storm unless that dust magically vanishes (I'm not going to do any vacuuming until the weekend, so it won't be vanishing from my house any time soon! ;-)). 

Tropical Storm Douglas
As for our friend who visited Hawaii. He's had a few pineapple-themed umbrella drinks and is now drunkenly staggering off into the sunset (well, heading west at 17mph anyway): 

He's currently at 22.9N, 163.3W and has now weakened to a strong Tropical Storm with winds of 70mph, central pressure 993mb (TS range: 39-74mph). There is no longer any vorticity in the highest level of the troposphere, just at the lowest-to-mid-levels, which means he's definitely a Tropical Storm and not a Hurricane. The wind shear is really taking it's toll because we can see the center in the satellite imagery, and what's left of the convection is all to the north: 


He may be a weaker TS than they say at this point, but he's pretty much going to wind down and fizzle out in a couple of days. I think this will be my last update on Douglas. 

By the way, did you realize that...
Hahaha... (thanks to hubby for pointing this one out to me). :-) 

And with that gem, I'll bid you adieu for today. 
J. 

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 local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know. 
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Sunday, July 26, 2020

Hurricane Douglas and the Atlantic Blob: July 26, Update A

Anyone else go to free virtual Comic Con online this weekend? :-) 
(Image from 'A Damn Fine Cup of Culture' blog, who may have got it from IMDB)

Hurricane Douglas
He has weakened a little to a mid-sized cat 1 storm with winds of 85mph, central pressure of 989mb. This seems about right to me. He still has quite a lot of convection, which we can see from the satellite imagery:

This is because he is over warm water. Although he is slowly weakening, it looks like the islands got a lot of rain and perhaps some strong thundery weather today. In addition to the convection, he still has some circulation throughout the troposphere, but it's much weaker in the upper troposphere now compared to a few days ago which backs up his cat 1 status. 

He's at 22N, 157.3W, heading WNW at 16mph and he'll continue moving past the island chain tomorrow before heading west:

Stay safe out there!

Atlantic Blob
Our Atlantic Blob now officially has a 80% chance of developing according to the NHC. I would say that he is currently somewhere around 11N, 38W, heading WNW at 15-20mph. You can see him as a large mass of disjointed clouds swirling in the Atlantic:

He has some circulation in the lower half of the troposphere, but it isn't very well developed at the moment and he certainly doesn't have a lot of convection - especially on his northern side: 


The lack of convection is because he's having a lovely chat with the Saharan Air Layer over a nice cup of tea:

They may name him tomorrow, but until he finished his jaffa cakes (with his tea of course) and moves along, he'll be restricted in growing - just like we saw with Gonzalo. 

At the moment, I think he'll continue on his generally westward track, maybe heading due W or a little southward. If he heads a little southward, he'll have a chance of getting stronger, but if he continues W or WNW, then the SAL between him and the Caribbean will play into keeping him weak. 

That's it for this weekend. 
Toodle pip, 
J. 

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 local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know. 
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Saturday, July 25, 2020

Remains of Gonzalo, Hurricane Hanna, Hurricane Douglas, and the Atlantic Blob: July 25, Update A

Saturday quiz time... 
25+ Best Wine Memes | Pringles Memes, Drinking Memes
Hmm. Tricky. What do you think? ;-)

Yesterday's Tropical Storm Gonzalo is now a bit of a will-o-the-wisp. Grenada had breezy winds of around 30mph and maybe a drop of rain. He's pretty much dissipated, so this is the last update on Mr TS Gonzalo.

Hurricane Hanna
She was finally upgraded to a hurricane this morning and is currently a cat 1 storm with winds of 85mph, central pressure 975mb. She did get close to cat 2 with winds of over 90mph (cat 2 range: 96-110mph) as she approached the Texas coastline, but since landfall has decreased in intensity a little. Landfall was on Padre Island in Texas about 3 hours ago (5pm CDT), and she is currently crossing Texas on her way to Mexico:


You can see that she is deteriorating quite rapidly as she interacts with land and her convection has decreased quite a lot. 

She's currently at 26.7N, 97.5W, heading WSW at 8mph. Her plans are to cross the US/Mexico Border and then settle down in Mexico. As we know, storms don't really care about walls. ;-) 
Unless something odd happens, I think this will be my last update on Hurricane Hanna as well as she's expected to be a Tropical Depression tomorrow. 

Two down, two to go.... :-)

Hurricane Douglas
Meanwhile, over in the Pacific, things are looking much better for Magnum PI and his pals on Hawaii (by the way, we've been re-watching the classic shows from the 80s and it is a hoot! :-)).

Douglas is now a cat 1 storm with winds of 90mph, central pressure 982mb, which makes him a mid-to-strong cat 1 (cat 1 range: 74-95mph). He is currently at 19.7N, 150.7W, heading WNW at 16mph and the track takes him close to the Big Island of Hawai'i tonight and passing near/over Oahu tomorrow: 

As you can see, he's not quite as well formed as he was even yesterday because of a bit of dry air (although that's decreasing now) and some wind shear: 

He has just moved back into an area of slightly warmer water with sea surface temperatures of 26 deg C, but he will continue to get weaker as he gets closer to the islands because the wind shear is also increasing. We can see the impact of the wind shear already because the clouds are streaming off to the northeast. The NHC forecast that he'll be in the Oahu area with winds of around 80mph, so as a relatively weak cat 1 storm. He may actually be a little weaker, but not by much - s0 expect a strong Tropical Storm/weak cat 1. I agree with the NHC on their the track and generally in their intensity forecast. 

Atlantic Blob
And so we return to the hurricane bowling alley with another blobette... 

He currently has a 50% chance of development in the next 48 hours, so I'll have a proper look at him tomorrow as it's wine-o-clock here. :-)

The next name is Isaias. We've never had an Isaias before! Hurricane names are on a 6-year rotation so, for example, the last time we had a Tropical Storm Hanna was in 2014. In 2014, that was actually the last storm of the Atlantic season in late October 2014. However, 6 years before that, in 2008, Hurricane Hanna was in late August/early September, and she was followed by the disastrous Hurricane Ike which caused 195 fatalities and $38 billion in damage (2008 dollars). When a storm is so damaging, they retire the name. So hence needing a new 'I' name. 

Ciao for now,
J. 

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 local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know. 
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Tropical Storm Gonzalo, Tropical Storm Hanna, Hurricane Douglas: July 24, Update A

Aww, bless him! Dr. Fauci really doesn't want anyone to catch anything this year...  


(adapted from a tweet I saw) ;-) 

Tropical Storm Gonzalo
He continues to behave - continuing to weaken from his interactions with the Saharan Air Layer. He is officially still a TS with winds of 40mph, central pressure 1009mb, but officially he's barely one as the wind range is 39-73 mph. There is a plane in the system at the moment investigating, so he could be downgraded to a Tropical Depression before even getting to the Caribbean. However, he still has some strong convection, which we can see from the satellite imagery: 
And there is still some circulation in the lower half of the troposphere. 

He currently at 10N, 57.1W (finally, making that WNW move), so as he gets close to land (or island), he will weaken even more and the NHC have now downgraded his forecast and expect him to dissipate over the weekend:
Not much more to say on him for today other than there will be a bit of rain, maybe a light breeze if you are in that neck of the woods. 

Tropical Storm Hanna
She's currently at 27.1N, 94.8W, heading W at 8mph. She's certainly got stronger since yesterday and now has winds of 65mph, central pressure at a low 992mb, which makes her a strong Tropical Storm (TS range: 39-73mph). 

I've been going with the NHC forecast track for this one and it's pretty consistent - making landfall in southern Texas somewhere near Padre Island on Saturday (tomorrow): 
I do think they have the center slightly too far to the east and it should be closer to 27.1N, 95.5W but I'm sure they'll fix that soon enough.

The NHC intensity forecast is now in alignment with my thinking - she'll be a hurricane at landfall. In my opinion, she is already a hurricane, so she may even make it to cat 2 before she makes landfall! There is very little wind shear and the water is warm. There is some dry air in the lower and middle levels of the troposphere, so that may keep her as a cat 1 storm before landfall, but that's about all I see.  
Her circulation (vorticity) is really strong throughout the entire troposphere, which is a signal of a hurricane. You know, I think it's time for a <Science Alert!>.... 

<Science Alert!> Vorticity: I keep dropping this magical word that tells me all about the storm structure, but what is it? Well, a storm has 'circulation', and it's pretty obvious what that is, right? It simply means that a storm is going around a central point, like a carousel. Vorticity, is essentially the way we measure the amount of circulation that a storm has. It's a very useful tool and I've used it for ages - next to a corkscrew for opening yummy wine bottles, it's my favourite (with a 'u') tool during hurricane season. ;-)

Although satellite imagery is one piece of the puzzle, the biggest clue about what sort of storm we have is the vorticity and what it looks like in different levels of the troposphere, because that gives us a glimpse into the structure of the storm. 

All types of stormy weather have a recognizable vorticity signal in the troposphere. Like a fingerprint, you can figure out what sort of storm system you have if you know what and where the vorticity is. The vorticity for low pressure fronts looks different compared to tropical storms. For low pressure fronts, the vorticity stretches out in a long line. For proper, grown-up, tropical cyclones, the vorticity is confined and generally circular. 

You can also tell how strong a tropical storm is depending on how strong the vorticity is and how high into the troposphere that signal can be seen. A Tropical Storm ALWAYS has a vorticity signal that reaches the middle of the troposphere (around 500mb) because this indicates that there is some deep convection (aka big thundery clouds). A Hurricane ALWAYS has a vorticity that reaches the upper level of the troposphere (around 200mb) because this indicates even strong convection and activity<End Science Alert!> 

We have a couple of storms out there, so let's have a look at the vorticity signals for TS Gonzalo and TS Hanna.

<Technical Alert!> Vorticity Maps:

Here is the vorticity map for 850 mb (almost the lowest level of the troposphere): 

You can see the signal of TS Gonzalo just off South America - the orange splodge (technical term), very conveniently covered by a Tropical Storm symbol. And you can also see the signal for TS Hanna in the Gulf, which is a big red (almost white hot) splodge - also conveniently covered by a Tropical Storm symbol (whoever is dropping those symbols has very good aim, don't they? ;-)) Green is very mild vorticity, yellow is a little stronger, orange is fairly decently strong, red is very strong, and white is really super-duper strong! Already you can tell that Hanna's circulation (vorticity) is stronger in the lowest levels of the troposphere compared to Gonzalo's circulation. 

Now let's look a little higher in the troposphere. Here's the map for 500mb (the middle level of the troposphere):

Again, you can see the difference between TS Gonzalo and TS Hanna - actually, in this case Gonzalo's mid-level vorticity isn't in alignment with his lower level. This indicates that the vortex isn't quite in alignment, and is frequently (but not always) associated with wind shear. TS Hanna meanwhile still has almost white hot vorticity at the mid-levels, meaning she has strong circulation. 

And here's the map for 200mb (the upper levels of the troposphere):

In this upper level map, you don't see any signal for Gonzalo. That's because he's not a hurricane, or even close to being a hurricane - there is no upper level circulation. However, Hanna is already at a yellow level, which means she's already a hurricane.  And the stronger the signal is at these lofty high levels of the troposphere, the stronger the hurricane. 

These amazing maps are produced by the University of Wisconsin-Madison's Cooperative Institute for Meteorological Satellite Studies - and a jolly good job they do too! To see them for yourselves in the future, click on the link above. If you followed my instructions on how to find data on the SAL a few days ago, this page should look awfully familiar. As before, go to the second map on the page (Regional Real Time Products) and click on the area of the world you are interested in. For the examples above, I clicked over the North Atlantic. From the drop-down menu, chose 'Winds & Analyses'. In the top panel, you'll see a whole array of buttons - including the 850mb, 500mb, and 200mb Vorticity. Clicking on those will give you maps like the ones above. This is definitely one of my favourite websites! You can even go back in 3-hour chunks of time and see the vorticity for a storm evolve or move around. It'll provide you with hours of fun and entertainment - all from the comfort of your own living room! :-) <End Technical Alert!>

For those who live north of the point of landfall, the storm surge will be high as she pushes water on shore. NOAA's Tides & Currents website: https://tidesandcurrents.noaa.gov/ will give you storm surge information for your local area. To see instructions on how to navigate this, read the Technical Alert in this TS Cristobal post. For Corpus Christi, the storm surge is already almost 1.5 ft above normal... 


More on this one tomorrow. 

Hurricane Douglas
Meanwhile, over in the Pacific, Hurricane Douglas has calmed down a wee bit. He is now 'just' a major cat 3 storm with winds of 115mph, central pressure of 971 mb, which makes him a weak cat 3 storm (cat 3 range: 111-129mph). He still has a strong eye, but his convection is a lot lighter than yesterday's deep red and orange cold cloud tops:

This is because he has moved over colder water now - temperatures are around 25 deg C. There isn't much wind shear, but there is some drier air ahead of him which is also playing into his weakening as you can see from the south and southeastern side of the storm, which is pulling that dry air into his system. 

He is currently at 18.2N, 145.9W. He's heading WNW at a very rapid 20mph and will reach the Hawaiian Islands on Sunday: 
He'll remain over cooler waters as he approaches Hawaii, and if that dry air continues, he may be a cat 1 as he gets close to the islands on Sunday. There is some wind shear ahead of him - closer to the Big Island - so if that persists, that will also help bring him down a notch. By the time he gets to Oahu, he may just be a Tropical Storm - but let's see whether he gets downgraded to a cat 2 tomorrow first. A Hurricane Hunter plane is currently gathering data from the system so that will help really get a handle on his intensity. 

Now you've learned about vorticity maps...  in the mid-level (500mb) and upper level (200mb) of the troposphere for the vorticity map for Hurricane Douglas, you can also see the vorticity for Hanna (unmarked on these Pacific Ocean maps): 


See the stronger vorticity signal for Douglas compared to Hanna's in the upper troposphere? An indication of a stronger hurricane. Easy, right? 

Until tomorrow!
Toodles,
J. 

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 local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know. 
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