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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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
456. IKE
Quoting TOMSEFLA:
has the recon found a west wind at the lower levels in gus?


Not yet.

Lowest pressure.... 1011.5 mb's.

72 hour ECMWF...

Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting TheDawnAwakening:
Are the HH in Hermine yet?
Recon is approaching, but have yet to descend.

181630 2548N 09403W 3925 07762 0442 -154 -159 165011 012 /// /// 03
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Quoting hurricanerunaway:
Hello! New here, but have been lurking since the beginning of hurricane season. I am from SE Texas on the TX/LA border. I know that Hermine is heading for STexas...but, it's pretty breezy here now. We got nothing from Alex...kinda worries me. I REALLY dislike GOMEX blowups!!!


Luckily where at the beginning of September so storms at the position where Hermine is rarely come that far North. If we were experiencing this at the end of September when frontal boundaries make their appearance that far South, you up there towards Houston to the TX/LA border would had to worry about Hermine so you should be safe from this one.
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Quoting TOMSEFLA:
has the recon found a west wind at the lower levels in gus?


no because they are not yet where they need to be to find that
Member Since: March 10, 2010 Posts: 1 Comments: 7367
Quoting Neapolitan:


Actually, it's a storm, an inaminate object, meaning that it's both asexual and gender-neutral. But thanks for pointing out my typo; fixed. ;-)


But she's been anthropomorphized and is a lady. ;)
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Quoting MississippiWx:
Hey, guys. I haven't been on in a few days...been too busy watching football and such. I see we have Hermine, though. I must be honest and say I never thought she would develop from that mess in the BOC. Amazing to see how rapidly she developed, though. I guess I shouldn't say what I think will happen with Gaston because the opposite will happen. :-p

Anyway, Hermine moves us to 8-3-2...possibly 8-4-2 by the end of the day. Igor should easily be here by the end of this week.
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has the recon found a west wind at the lower levels in gus?
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Hey, guys. I haven't been on in a few days...been too busy watching football and such. I see we have Hermine, though. I must be honest and say I never thought she would develop from that mess in the BOC. Amazing to see how rapidly she developed, though. I guess I shouldn't say what I think will happen with Gaston because the opposite will happen. :-p

Anyway, Hermine moves us to 8-3-2...possibly 8-4-2 by the end of the day. Igor should easily be here by the end of this week.
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Quoting Neapolitan:


Actually, it's a storm, an inaminate object, meaning that it's both asexual and gender-neutral. But thanks for pointing out my typo; fixed. ;-)
Welcomed.
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447. JLPR2
Here we go again with the I'm going to fire some convection game to make you wonder. :\
LOL!


-------------
Hey everyone, I see Hermine is taking advantage of the hot Gulf Of Mexico.
Member Since: September 4, 2007 Posts: 7 Comments: 8499
Are the HH in Hermine yet?
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Quoting hydrus:
A sprout.


Maybe a leaf stem, but as small as I will go.
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Quoting hurricanerunaway:
Hello! New here, but have been lurking since the beginning of hurricane season. I am from SE Texas on the TX/LA border. I know that Hermine is heading for STexas...but, it's pretty breezy here now. We got nothing from Alex...kinda worries me. I REALLY dislike GOMEX blowups!!!


I am in the same area as you. Welcome....
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Quoting TheDawnAwakening:


Perhaps a twig.
A sprout.
Member Since: September 27, 2007 Posts: 1 Comments: 20507
Quoting washingtonian115:
It's a she.


Actually, it's a storm, an inaminate object, meaning that it's both asexual and gender-neutral. But thanks for pointing out my typo; fixed. ;-)
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Hello! New here, but have been lurking since the beginning of hurricane season. I am from SE Texas on the TX/LA border. I know that Hermine is heading for STexas...but, it's pretty breezy here now. We got nothing from Alex...kinda worries me. I REALLY dislike GOMEX blowups!!!
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Humberto, Part Duex?
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Quoting MiamiHurricanes09:
Yeah, a small limb, lol.


Perhaps a twig.
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Quoting Cotillion:
ATCF is the same as the 1pm advisory.


I was about to say that too.
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Quoting 1900hurricane:

Woah, that from NRL?

Nevermind, for some reason, thought that Gaston was 10L. My mistake.
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Texas you're next...Stay safe.
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Quoting flsky:

Do you mean Jeanne?

Yes JEANNE
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Quoting Neapolitan:
Hermine up to 50 knots/60 mph. Yeah, he'll be a hurricane by landfall. No doubt about it...
It's a she.
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Quoting TXCaneCrasher:


thank you


Again...it's a weather forum for all tropical weather discussion. People are staring to do the same thing with this storm as they did with Earl. Everybody is equally talking about Hermine as they are about Gaston so there shouldn't be any crying. Its a free world huh.
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Core close-up:

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Member Since: August 10, 2007 Posts: 0 Comments: 3224
ATCF is the same as the 1pm advisory.
Member Since: August 23, 2008 Posts: 7 Comments: 5300
Quoting jurakantaino:
Yes is more of a threat to Mexico and Southern Texas, Gaston is a potential damage to the eastern and perhaps central caribbean, an area of more than 15 million people. If it strengthing of course.


Exactly, IF. Just wish there were more posts regarding the present (Hermine) instead of the 7-10 days from now (Gaston).
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Quoting 1900hurricane:

Woah, that from NRL?
ATCF.
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Hermine up to 50 knots/60 mph. Yeah, she'll be a hurricane by landfall. No doubt about it...
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We have a nice thunderstorm here in Central Palm Beach County, looks worse than Bonnie lol
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Quoting MiamiHurricanes09:
AL, 10, 2010090618, , BEST, 0, 241N, 966W, 50, 995, TS,

Woah, that from NRL?
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Quoting MiamiHurricanes09:
I'll go on a limb and say that Recon finds Hurricane Hermine.
Dvorak shows a strengthening Hermine.
Member Since: September 27, 2007 Posts: 1 Comments: 20507
Quoting TheDawnAwakening:
Well our wave around 15-16w just moving off the African coastline has been analyzed by the NHC and they mention it in their TWD. So I expect it to be circled tonight or tomorrow.

Around 8 P.M tonight or 2 A.M tomorrow
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Quoting TheDawnAwakening:
ex Gaston does look to be on its way to becoming a tropical storm again. Convection developing is deep and the circulation is getting tighter. However I would still give him another 24 hours before any significant development would occur when he is in a more moist environment and wind shear is minimal. Also hopefully he spares Hispaniola and Puerto Rico any more rain problems, and moves to the south of these islands so he doesn't get shreded.


But it also kind of looks like that he might be barely sliding North of the islands which would be ironic since this storm at first seemed to be destined for the Caribbean.
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Quoting btwntx08:
guys hermine is more a threat than gaston
Yes is more of a threat to Mexico and Southern Texas, Gaston is a potential damage to the eastern and perhaps central caribbean, an area of more than 15 million people. If it strengthing of course.
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Quoting btwntx08:
guys hermine is more a threat than gaston
Yes is more of a threat to Mexico and Southern Texas, Gaston is a potential damage to the eastern and perhaps central caribbean, an area of more than 15 million people. If it strengthing of course.
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Quoting TheDawnAwakening:
Well MH09, I would agree with your statement and also say that this is not a very big limb.
Yeah, a small limb, lol.
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Hermine is going to probably cause more damage and trouble than Earl did. Kind of ironic considering Earl was nearly a Cat 5 projected to wreak a bit of havoc along the outer banks, eastern seaboard, Cape Cod, etc. and yet here we have Hermine which developed so rapidly, will only reach Cat1(90mph?) status given the rapid strengthening and improved characteristics on satellite.

Another lesson that Mother Nature will do what she wants, when she wants, and not even the best computer models/ensembles can pick up on everything.
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HH are busy today
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Well MH09, I would agree with your statement and also say that this is not a very big limb.
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Quoting Bielle:

What?


Sorry, troll slapping would have been a better choice of words lol
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AL, 10, 2010090618, , BEST, 0, 241N, 966W, 50, 995, TS,
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Quoting btwntx08:
guys hermine is more a threat than gaston


thank you
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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.