Hurricane watches for Mexico and Texas as Hermine suddenly develops

By: Dr. Jeff Masters , 4:15 PM GMT on September 06, 2010

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Hurricane watches are up for the Texas/Mexico border region as fast developing Tropical Storm Hermine steams towards the coast at 13 mph. Hermine was a tropical depression twelve hours ago, got its name just six hours ago, but already is a threat to intensify into a hurricane by tonight. It's remarkable how fast Gulf of Mexico disturbances can blow up into strong tropical storms, when the right mix of warm waters and low wind shear develops. Indeed, water temperatures are a very warm 30°C, wind shear is a low 5 - 10 knots, and the atmosphere is very moist in the Gulf--ideal conditions for a tropical storm. Hermine promises to be a very wet storm, and latest long range radar out of Brownsville, Texas shows a large area of heavy rain has moved ashore over southern Texas and northern Mexico, with radar estimated rainfall amounts already exceeding two inches in a few areas along the coast. Radar loops show that an eyewall may be beginning to form, and I expect this process will continue through the afternoon and early evening. Satellite imagery shows that Hermine is getting more organized, with vigorous thunderstorms with very cold tops building, low-level spiral bands developing, and improving upper-level outflow occurring on all sides except the west. There is some dry air to the west of Hermine over land that is restricting the storm's development there.

Forecast for Hermine
Hermine doesn't have much time over water before it comes ashore, which is a good thing. Hermine is organizing rapidly, and has a shot at reaching hurricane strength before the center moves ashore late tonight, near midnight. Neither the GFDL or HWRF models develop Hermine into a hurricane, but the HWRF model does predict that tropical storm force winds of 39+ mph will affect the coast as far north as Corpus Christi, Texas. Heavy rain will be the main threat from Hermine, though isolated tornadoes may also cause damage, particularly over South Texas. Hermine is expected to accelerate through Central Texas Tuesday and Wednesday, and the storm's rains will help alleviate moderate to severe drought conditions affecting Central Texas.


Figure 1. Early afternoon radar image of Tropical Storm Hermine.

Gaston continues to suffer from dry air
The remains of Tropical Storm Gaston are now approaching the northern Lesser Antilles, and residents can expect a few heavy rain showers and wind gusts up to 40 mph beginning late this afternoon and continuing into the night. A pass from the ASCAT satellite this morning at 9:03 am EDT showed a large region of 25 mph winds on the north side of Gaston's circulation, and these winds will move into the northern Lesser Antilles late this afternoon. Latest radar out of Martinique doesn't show much in the way of heavy rain, and satellite imagery confirms that the thunderstorm activity associated with Gaston's remains is quite sparse. Gaston does have developed a well-organized surface circulation, but not enough heavy thunderstorm activity to be considered a tropical depression. A large amount of dry air surrounds Gaston's remains on all sides, as seen on water vapor satellite loops.


Figure 2. Morning satellite image of the remains of Gaston, approaching the Lesser Antilles Islands.

Forecast for Gaston
Dry air will continue to be the major impediment to development for Gaston, and the system is unlikely to become a tropical depression today. However, wind shear, which is currently a moderate 10 knots, is forecast by the latest SHIPS model run to fall very low, 0 - 5 knots, tonight through Wednesday. With almost no wind shear affecting it, Gaston will a better chance of keeping the moisture from its heavy thunderstorms near it core on Tuesday. This will insulate the storm from the dry air surrounding it. The atmosphere is also moister in the eastern Caribbean, further increasing the chances of development. I believe it is probable Gaston will become a tropical depression again on Tuesday. NHC is currently giving Gaston a 70% chance of developing into a tropical depression by Wednesday, which is a reasonable forecast. The models don't give much support for Gaston surviving past Wednesday, since many of them have the storm hitting the rugged island of Hispaniola, disrupting the storm.

Heavy rain showers and gusty winds from the storm will affect Puerto Rico Tuesday morning through Wednesday afternoon. This activity will spread to the Dominican Republic Tuesday afternoon through Thursday morning. Assuming dry air and an encounter with Hispaniola's high mountains do not destroy Gaston, heavy rain from the storm should move over Haiti, eastern Cuba, the Turks and Caicos Islands, and Jamaica Wednesday night and Thursday morning. Though none of the global dynamical computer models are showing this, should Gaston survive the dry air and its coming encounter with Hispaniola, the storm will find itself in a very favorable environment for development in the Western Caribbean late in the week, and could intensify into a hurricane by next weekend.

Elsewhere in the tropics
The models are fairly unanimous in predicting development late this week of a tropical wave expected to emerge from the coast of Africa on Tuesday or Wednesday. The next storm will be called Igor, and let's hope it doesn't live up to its fearsome-sounding name!

Next post
There will be an update by early this evening.

Jeff Masters

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557. MiamiHurricanes09
6:49 PM GMT on September 06, 2010
Quoting TXEER:


Heavens yes...let's hope for development so Gaston can hit land...destroy property and kill people...good grief some of you people!
What are you talking about?
Member Since: September 2, 2009 Posts: 130 Comments: 21032
556. Neapolitan
6:49 PM GMT on September 06, 2010
Found this and posted it on the earlier blog; I'll do so again now since more people are logged in:

Poor little Gaston.

There have been 17 consecutive TWOs since the little guy had his own discussion; it's been 102 hours (and counting) since the little swirl that could(n't) got any respect from the NHC, or since he was able to contribute even the tiniest bit of ACE to the seasonal total, or since he could really make an impression on anyone but a few mathematical model makers. It's not his fault; he was born and raised in a tough neighborhood at a disadvantageous time, and nearly his entire youth has been spent being harshly tugged at by wind shear while simultaneously being beset on all sides by an airborne lobe of the Sahara that refuses to relinquish its arid and vice-like grip on him. And as if that's not enough, he wasn't given a noble, heroic name, but was rather saddled with the pathetic, ambiguously-pronounced appelation known best by most as an arrogant, harrassing murderer killed by his own stupidity in an old Disney cartoon. Now many--including some right here in this forum--want him killed, want him gone, want him to just go away, as though his very existence is somehow an affront to them, or a bother, like a boil to be lanced or a scab to be picked.

And yet he survives...

When Gaston was born last Wednesday evening, Earl was a major storm who still hadn't reached his peak strength, and Fiona was not even halfway through her short life. Now, five days later, Earl's remnant energy is spinning harmlessly away over the frigid North Atlantic, while Fiona days ago devolved into a few clouds and brief Bermudan squalls...and, still, Gaston limps bravely along. He'll be stuck in the shadows for a couple of days still--shadows from whence he's never fully emerged--while Hermine has her few days in the spotlight; and Africa may be right now spinning off a system that'll grab that spotlight about the time Hermine exits the stage.

It's folly to anthropomorphize inanimate objects, but if ever there was a life lesson to be learned about persevering in the face of all odds, Gaston's the one to teach it. How it's going to end for him is anyone's guess--his predicted future ranges from growing into a damaging and destructive Caribbean storm to dissipating into a few fluffy and harmless cumulus clouds over some Dominican mountain. But I say he's already earned our respect, not for what he's done, but for what he hasn't: quit.

Poor little Gaston? No: you go, Gaston!
Member Since: November 8, 2009 Posts: 4 Comments: 13306
555. washingtonian115
6:49 PM GMT on September 06, 2010
Quoting leo305:


I know right
Get use to it....that's just how they are now.Mmmm maybe I should go back in the past to stop the future of TWC from being crappy....
Member Since: August 14, 2010 Posts: 10 Comments: 15738
554. KEEPEROFTHEGATE (Mod)
6:48 PM GMT on September 06, 2010
Quoting moonlightcowboy:



Keep, we could've done without that shot, friend! ;{
keep yer head up and yer eyes wide open
Member Since: July 15, 2006 Posts: 165 Comments: 52406
551. Levi32
6:48 PM GMT on September 06, 2010
50kt colors are showing up on velocity imagery periodically, but again this doesn't look like it's near a hurricane yet.

Member Since: November 24, 2005 Posts: 628 Comments: 26465
When a storm looks good in WV, dry air is not an issue.
Member Since: August 10, 2007 Posts: 0 Comments: 3217
GR2AE also shows that Hermine has indeed become better organized recently.
Member Since: July 6, 2010 Posts: 109 Comments: 30310
Quoting TropicalAnalystwx13:
Hermine:



Eyewall looking nice.
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Radar presentation is improving but on satellite this doesn't look like a hurricane yet. We need a recon in there soon or we'll have to wait for landfall to know what kind of winds this is packing.

Member Since: November 24, 2005 Posts: 628 Comments: 26465
Quoting AllStar17:
Of course the Weather Channel is showing Storm Stories and there is a tropical system active and approaching land.


That's because they didn't have time to get Cantore or anyone else there...
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Still staying firm with my belief that this wont re-develop until Tuesday or Wednesday.


We'll see what happens.
Member Since: June 9, 2007 Posts: 4 Comments: 15718
Quoting PtownBryan:
Hallelujia! Hallelujia! It is raining in Pearland, Texas! Thank You Lord! Bring it Hermine! I got some brown patches of grass calling your name! =)
Am south of you, we've had 1 1/2 of rain so far
Member Since: July 17, 2010 Posts: 0 Comments: 2
Hermine:

Member Since: July 6, 2010 Posts: 109 Comments: 30310
534. Levi, I think I said "thanks" and said it was interesting commentary. I would still like StormW's thoughts. What part of that can't you understand?
Member Since: July 9, 2006 Posts: 184 Comments: 29594
Anyone know if the steering is different with Hermine being stronger? It seems as if the models were all showing a minimal TS?
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Hallelujia! Hallelujia! It is raining in Pearland, Texas! Thank You Lord! Bring it Hermine! I got some brown patches of grass calling your name! =)
Member Since: July 5, 2010 Posts: 0 Comments: 170
Quoting Hurricanes101:


atcf has the pressure now at 1011, I think the system is falling apart or barely hanging on

recon is on the SE side of the system and finding no west winds whatsoever
I doubt the pressure was as low as the ATCF had it previously (due to the lack of factual information from Recon). And no, the system is not falling apart, assumptions like that are premature considering that the circulation remains vigorous and well-defined.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
Quoting will40:
Hurricane101 heres the one from earlier


17:49:30Z 17.267N 57.150W 961.7 mb
(~ 28.40 inHg) 443 meters
(~ 1,453 feet) 1011.7 mb
(~ 29.88 inHg) - From 238° at 16 knots
(From the WSW at ~ 18.4 mph) 18.7°C
(~ 65.7°F) 13.4°C
(~ 56.1°F) 19 knots
(~ 21.8 mph) 56 knots*
(~ 64.4 mph*) 21 mm/hr*
(~ 0.83 in/hr*) 47.2 knots* (~ 54.2 mph*)
Tropical Storm*


ok good to know

tells me that Ex-Gastons circulation is very small
Member Since: March 10, 2010 Posts: 1 Comments: 7233
Quoting moonlightcowboy:
StormW, in this WV shot is this energy spent off to the northwest by Gaston? I can't see what's causing that - no ull, no upper trough located there. Unless it's the southeasterly flow that has managed to separate some of the energy from the system in some layer of the ridge?

Appreciate your thoughts on this. TIA.






SFC maps don't show any trough there. Marine charts don't show a trough. But interesting commentary just the same. If indeed easterly flow is piling up, I'm thinking we should see Gaston slowing and convection growing around the coc.

Again, I'd like to hear StormW's thoughts on the scenario there. Thanks, Levi.


No need to bite me people answer the questions directed at me all the time lol. Storm didn't even see your question because of the comment rate in here.

Just because a trough isn't analyzed on the surface map doesn't mean there isn't one. While it is impossible to know the pressure field in the area, one can see the convergence zone which has set up extending northwest of Gaston with the bending of the wind field and the visible satellite loops show the look of an elongated trough northwest of the system, which is common when they are weak.

Member Since: November 24, 2005 Posts: 628 Comments: 26465
Quoting KEEPEROFTHEGATE:
WOW..
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It's a good thing Hermine doesn't have much room left over water.She's pulling a Alex on us.
Member Since: August 14, 2010 Posts: 10 Comments: 15738
531. 7544
Quoting Sfloridacat5:
Gaston's looking the best he's been in a long time. Convection firing east and west of its center.


agree looks like hes going wnw now ?hmmm

cmc makes a strong igor moving west

but gfs says igor goes fishing Link
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Quoting Sfloridacat5:
Gaston's looking the best he's been in a long time. Convection firing east and west of its center.
I would like to see it persist through the evening. Even if convection does increase now, it won't be worth anything if it just dissipates around sun set.
Member Since: September 2, 2009 Posts: 130 Comments: 21032
Hurricane101 heres the one from earlier


17:49:30Z 17.267N 57.150W 961.7 mb
(~ 28.40 inHg) 443 meters
(~ 1,453 feet) 1011.7 mb
(~ 29.88 inHg) - From 238° at 16 knots
(From the WSW at ~ 18.4 mph) 18.7°C
(~ 65.7°F) 13.4°C
(~ 56.1°F) 19 knots
(~ 21.8 mph) 56 knots*
(~ 64.4 mph*) 21 mm/hr*
(~ 0.83 in/hr*) 47.2 knots* (~ 54.2 mph*)
Tropical Storm*
Member Since: September 19, 2005 Posts: 2 Comments: 4066
Member Since: August 10, 2007 Posts: 0 Comments: 3217
527. JLPR2
Quoting Sfloridacat5:
Gaston's looking the best he's been in a long time. Convection firing east and west of its center.


Yeah, it's actually seems to be staying in place instead of being blown to the west.
Member Since: September 4, 2007 Posts: 7 Comments: 8459
Quoting Sfloridacat5:
Gaston's looking the best he's been in a long time. Convection firing east and west of its center.


atcf has the pressure now at 1011, I think the system is falling apart or barely hanging on

recon is on the SE side of the system and finding no west winds whatsoever
Member Since: March 10, 2010 Posts: 1 Comments: 7233
Quoting AllStar17:
Of course the Weather Channel is showing Storm Stories and there is a tropical system active and approaching land.


I know right
Member Since: April 17, 2010 Posts: 0 Comments: 1753
Quoting KEEPEROFTHEGATE:



Keep, we could've done without that shot, friend! ;{
Member Since: July 9, 2006 Posts: 184 Comments: 29594
Quoting mojofearless:


Welcome to WU! Where are you from?


I'm in Elvis town - Memphis. We don't get hurricanes but we get rain from them sometimes.

Actually, in July, 2003 we had a derecho with 100+ mile an hour winds blow thru that everybody called "Hurricane Elvis". Is that good enuff? :)
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Quoting Stormchaser2007:
Getting some awesome images from GE.

Recon heading in.

FULL IMAGE


Hey,

Go to GR2AE, and look at Hermine from there.
Member Since: July 6, 2010 Posts: 109 Comments: 30310
At this moment it doesn't really seem all that likely that Gaston will directly interact with the S portions of Hispaniola.

Member Since: June 9, 2007 Posts: 4 Comments: 15718
Gaston's looking the best he's been in a long time. Convection firing east and west of its center.
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Member Since: July 15, 2006 Posts: 165 Comments: 52406
Of course the Weather Channel is showing Storm Stories and there is a tropical system active and approaching land.
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517. xcool
Hermine going maker land fall in mx
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516. IKE
Quoting WeatherNerdPR:

Looks like Alex Part 2.


It's going to make landfall in the same general area of Northern Mexico...looks like to me.
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Quoting TheDawnAwakening:


Radar does not show this.
Right WV shows dry air moving out in wake of Hermine.
Member Since: August 10, 2007 Posts: 0 Comments: 3217
Quoting 1900hurricane:
Anyone see what I'm seeing?



Think I see a pinhole eye!

:P
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Hermine is exhaling, they tend to do that during the day especially
Member Since: April 17, 2010 Posts: 0 Comments: 1753
StormW, in this WV shot is this energy spent off to the northwest by Gaston? I can't see what's causing that - no ull, no upper trough located there. Unless it's the southeasterly flow that has managed to separate some of the energy from the system in some layer of the ridge?

Appreciate your thoughts on this. TIA.



Quoting Levi32:


Gaston has a surface trough extending from him to the northwest and there is speed-convergence there due to a burst of easterly wind on his northern side that becomes slower downstream. This causes the air to pile up which forces it to rise, causing the thunderstorms you see to the northwest of Gaston.



SFC maps don't show any trough there. Marine charts don't show a trough. But interesting commentary just the same. If indeed easterly flow is piling up, I'm thinking we should see Gaston slowing and convection growing around the coc.

Again, I'd like to hear StormW's thoughts on the scenario there. Thanks, Levi.
Member Since: July 9, 2006 Posts: 184 Comments: 29594
Hermine is quickly running out of room.
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Quoting CybrTeddy:

TCHP 2009 on this date.


2008


2007


2006


2005


Note, the TCHP map received a major upgrade in resolution after the 2008 season, so for '05-'08 it is higher than it looks but you get the picture.
Then 2010 must be the record...
Member Since: August 14, 2010 Posts: 10 Comments: 15738
Quoting cchsweatherman:
Right now, water vapor imagery as well as radar imagery shows some dry air from over Mexico seems to have gotten into Hermine's core recently.


Radar does not show this.
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Quoting StormW:

Looks like Alex Part 2.
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Getting some awesome images from GE.

Recon heading in.

FULL IMAGE
Member Since: June 9, 2007 Posts: 4 Comments: 15718

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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.