Intensifying Hermine closes in on the Texas/Mexico coast

By: Dr. Jeff Masters , 9:47 PM GMT on September 06, 2010

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Steadily intensifying Tropical Storm Hermine is closing in on the coast near the Texas/Mexico border, and should move ashore late tonight. Hermine became a tropical depression at 11pm last night, and could become a minimal hurricane by 11 pm tonight. Hermine's rate of intensification from nothing to a strong tropical storm is one of the fastest on record. It turns out that the extreme southwestern Gulf of Mexico's Bay of Campeche, where Hermine formed, is prone to these sort of rapidly intensifying tropical storms. The curvature and topography of the land help induce a counter-clockwise spin to the air over the region, which helps get tropical storms spinning up unusually quickly. Helping the spin-up process are the very warm 30°C waters, low 5 - 10 knots of wind shear, and moist atmosphere. 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 been drenching southern Texas and northern Mexico all afternoon, with radar estimated rainfall amounts exceeding two inches in a few areas along the coast. Radar loops show that an eyewall is attempting to form, but a region of dry air from over land spiraled into Hermine's core between 4 - 5pm EDT, disrupting eyewall formation. However, it now appears that Hermine has closed off its eye from this dry air, which should aid in intensification. Satellite imagery shows Hermine has vigorous thunderstorms with very cold tops, and improving low-level spiral banding.

Forecast for Hermine
Hermine doesn't have much time over water before it comes ashore, which is a good thing. The storm is steadily organizing, and has a shot at reaching hurricane strength before the center moves ashore late tonight, near midnight. 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. Late afternoon radar image of Tropical Storm Hermine. Note the band of dry air spiraling into the core of the storm from the north.

Gaston continues to suffer from dry air
An Air Force Hurricane Hunter aircraft spent the afternoon in Gaston's remains, and found a weak 1012 mb center of low pressure with only a limited region of westerly winds on the south side of the center of circulation. Top surface winds uncontaminated by heavy rain seen by their SFMR instrument were in the 30 - 35 mph range. The airplane found plenty of dry air in the storm's environment, and there are not enough heavy thunderstorms in ex-Gaston's circulation for it to qualify as a tropical depression. The remains of 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 early this evening and continuing into the night. 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. A large amount of dry air surrounds Gaston's remains on all sides, as seen on water vapor satellite loops.


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

Forecast for Gaston
There is little change to the forecast for Gaston's remains. Dry air will continue to be the major impediment to development, 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 its 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.

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, and Jamaica Wednesday night and Thursday morning. The models don't give much support for Gaston surviving past Wednesday. The ECMWF, GFS, NOGAPS, Canadian, and HWRF models all dissipate Gaston. However, two models--the GFDL and UKMET--predict that Gaston will survive the dry air and an encounter with Hispaniola, and pass far enough south of the island to find a favorable environment in the Central Caribbean for development on Wednesday. Wind shear will be low, water temperatures will be hot, and the atmosphere will be plenty moist. Gaston could intensify into a hurricane in the Western Caribbean by the end of the week, as predicted by the latest run of the GFDL model.

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.

Next post
I'll have an update in the morning.

Jeff Masters

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can someone post our radar tonight? it is an awesomely rainy night here!!!
Member Since: September 30, 2008 Posts: 0 Comments: 108
Quoting 954FtLCane:

you stink, man its comming down in sheets here


I worked down there cleaning up a bit after WILMA...and all I remember were those huge A$$ Mosquitoes that chewed through my screen windows and broke into the refrigerator and eat up all the Hot Dogs!!! The rain can not be helping your mosquito population!!

Member Since: August 18, 2008 Posts: 0 Comments: 2265
882. KYDan
Interesting WV loop of the NA.

Link
Member Since: Posts: Comments:
Quoting ShenValleyFlyFish:
Did you remember to throw out the frozen water jugs. I sat mine out in the open where brease could hit them.

Er, No, Sorry!
Was kind of busy today and, well, um, I forgot!
Nice idea to cool the atmosphere though.
You may have hit on the idea, to save the World.
Together, we could create an Ice Age next week!
ONWARD>>>>>>>>>
Member Since: October 24, 2005 Posts: 0 Comments: 24382
I'd prefer it rain during the day here in SFL..

but any rain is great, hopefully it rains all day tomorrow
Member Since: April 17, 2010 Posts: 0 Comments: 1753
Quoting IKE:


Yup...20-14 in the 3rd quarter.



lol.

ty ... I think I saw an Alligator in my front yard... wait someone's knocking...... alligator?
Member Since: September 30, 2008 Posts: 0 Comments: 108
Quoting IKE:


Yup...20-14 in the 3rd quarter.



lol.

ty ... I think I saw an Alligator in my front yard... wait someone's knocking...... alligator?
Member Since: September 30, 2008 Posts: 0 Comments: 108
Quoting stormwatcherCI:
You're welcome. Sometimes the discussions get so intense on here that your question might not be seen by the more knowledgable.
Agreed. Don't think that your questions/opinions are unwelcome here. The blog moves so fast at times of imminent landfall, that the knowledgeable, friendly folks that can shed light on things, cannot answer every post. Keep your chin up, and keep watching the skies.
Member Since: Posts: Comments:
gastom is now at 17.0N 60.0W via AVN sat
Member Since: June 13, 2009 Posts: 2 Comments: 12147
Quoting stormwatcherCI:
Where are you ?


Corpus.....about 8 miles from the GOM
Member Since: July 28, 2010 Posts: 0 Comments: 285
874. IKE
Quoting leo305:


go a little east, and you see the remnant 99L, erupting with convection, with a spin at the surface


Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting IKE:

Gaston hardly moving!!??
Weirdness rules.......
Member Since: October 24, 2005 Posts: 0 Comments: 24382
Quoting traumaboyy:


Very fair skies here in Northwest florida!! I would mention how dry it is...but since I live 45 miles from the Coast of the boiling GOMEX I DON'T NEED ANY RAIN!!!

you stink, man its comming down in sheets here
Member Since: September 30, 2008 Posts: 0 Comments: 108
Quoting pottery:

I see that.
That's why I mentioned the Lovely Warm Rain.
Serves you right........
Did you remember to throw out the frozen water jugs. I sat mine out in the open where brease could hit them.
Member Since: Posts: Comments:
Quoting pottery:

Not nessesarily...


great....now i am confused all over again. lol i guess it is back to the books for me!
Member Since: July 28, 2010 Posts: 0 Comments: 285
Quoting IKE:


go a little east, and you see the remnant 99L, erupting with convection, with a spin at the surface
Member Since: April 17, 2010 Posts: 0 Comments: 1753
867. IKE
Quoting 954FtLCane:
my dish is out, its mad crazy pouring here, is Boise still winning?


Yup...20-14 in the 3rd quarter.

Quoting GeoffreyWPB:
Did Hermine hit Houston yet?


lol.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting want2lrn:


I have learned to be patient, persistent but not to the point of annoying. lol We have had a couple of gusty showers here, but nothing major, we need the rain so this is good, hopefully it will stay somewhat docile.
Where are you ?
Member Since: October 9, 2008 Posts: 0 Comments: 8392
my dish is out, its mad crazy pouring here, is Boise still winning?
Member Since: September 30, 2008 Posts: 0 Comments: 108
Did Hermine hit Houston yet?
Member Since: Posts: Comments:
863. IKE
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting traumaboyy:


Very fair skies here in Northwest florida!! I would mention how dry it is...but since I live 45 miles from the Coast of the boiling GOMEX I DON'T NEED ANY RAIN!!!

Dont mention "rain" to Orca....
he has some sort of amazing powers....
Scary!
heheheheh
Member Since: October 24, 2005 Posts: 0 Comments: 24382
Quoting stormwatcherCI:
You're welcome. Sometimes the discussions get so intense on here that your question might not be seen by the more knowledgable.


I have learned to be patient, persistent but not to the point of annoying. lol We have had a couple of gusty showers here, but nothing major, we need the rain so this is good, hopefully it will stay somewhat docile.
Member Since: July 28, 2010 Posts: 0 Comments: 285
Quoting want2lrn:


Isn't that good news? From what i have heard (learned) on here in my brief time, that would tend to make it recurve sooner if it is stronger earlier?

Not nessesarily...
Member Since: October 24, 2005 Posts: 0 Comments: 24382
Quoting Leafgreen:

Exactly. It's surrounded by a thick border of moist air. Frequently African waves are accompanied by an adjacent SAL. Not this one.


Do we call that a "bloblet"?...

I don't think I can tolerate another GASSSSSS-STONE!!!
Member Since: Posts: Comments:
Quoting Neapolitan:
The area she made landfall is very wet, very warm, and very flat swamp; there's not a lot of instantaneous falling apart that's going to happen...


True.....

I remember Ernesto years ago that came up through the everglades....... and held or even gained a little strength!
Member Since: September 8, 2005 Posts: 0 Comments: 3805
Looks like the rain just faded away here in SE Texas (Houston) once it got west of 610. Everything in the Gulf has just faded also - probably be back tomorrow though.
Member Since: August 28, 2005 Posts: 0 Comments: 113
Quoting pottery:

And a Good Evening to you, my Friend.
Are you under Fair skies?


Very fair skies here in Northwest florida!! I would mention how dry it is...but since I live 45 miles from the Coast of the boiling GOMEX I DON'T NEED ANY RAIN!!!
Member Since: August 18, 2008 Posts: 0 Comments: 2265
Quoting blsealevel:


checking in on GOMEX storm i see it made land fall in Mex try to stay dry folks going to be a stormy night.
WOW nice shot.....
Member Since: September 30, 2008 Posts: 0 Comments: 108
Orca...
is your weather cooling down already?
or just a cool 'snap'?
Member Since: October 24, 2005 Posts: 0 Comments: 24382
851. want2lrn
1:54 AM GMT on September 07, 2010
Quoting Leafgreen:

Exactly. It's surrounded by a thick border of moist air. Frequently African waves are accompanied by an adjacent SAL. Not this one.


Isn't that good news? From what i have heard (learned) on here in my brief time, that would tend to make it recurve sooner if it is stronger earlier?
Member Since: July 28, 2010 Posts: 0 Comments: 285
850. 954FtLCane
1:54 AM GMT on September 07, 2010
OMG It's just pouring here in Fort Lauderdale
Member Since: September 30, 2008 Posts: 0 Comments: 108
849. pottery
1:53 AM GMT on September 07, 2010
Quoting traumaboyy:


LOL!!.....good evening sir!!

And a Good Evening to you, my Friend.
Are you under Fair skies?
Member Since: October 24, 2005 Posts: 0 Comments: 24382
848. thelmores
1:53 AM GMT on September 07, 2010
Hmmm....... Now THAT is a HUGE wave!

Igor might be one mean monger!

Member Since: September 8, 2005 Posts: 0 Comments: 3805
847. stormwatcherCI
1:53 AM GMT on September 07, 2010
Quoting want2lrn:
Thank you Stormwatcher
You're welcome. Sometimes the discussions get so intense on here that your question might not be seen by the more knowledgable.
Member Since: October 9, 2008 Posts: 0 Comments: 8392
846. blsealevel
1:51 AM GMT on September 07, 2010


checking in on GOMEX storm i see it made land fall in Mex try to stay dry folks going to be a stormy night.
Member Since: August 23, 2008 Posts: 0 Comments: 1918
845. traumaboyy
1:51 AM GMT on September 07, 2010
Quoting pottery:

AAAKKK!!!
You got me!!
85-86 F
GOM 87F
(sorry 'bout that!)


LOL!!.....good evening sir!!
Member Since: August 18, 2008 Posts: 0 Comments: 2265
843. pottery
1:50 AM GMT on September 07, 2010
Quoting Neapolitan:
The area she made landfall is very wet, very warm, and very flat swamp; there's not a lot of instantaneous falling apart that's going to happen...

Point...
Member Since: October 24, 2005 Posts: 0 Comments: 24382
842. Leafgreen
1:49 AM GMT on September 07, 2010
Quoting hydrus:
What caught my attention is that the air around the wave is similar to a steam bath..It should spin up rather quickly once out past the Cape Verde Islands...I-GOR..

Exactly. It's surrounded by a thick border of moist air. Frequently African waves are accompanied by an adjacent SAL. Not this one.
Member Since: July 8, 2008 Posts: 0 Comments: 26
841. want2lrn
1:49 AM GMT on September 07, 2010
Thank you Stormwatcher
Member Since: July 28, 2010 Posts: 0 Comments: 285
840. Neapolitan
1:47 AM GMT on September 07, 2010
The area she made landfall is very wet, very warm, and very flat swamp; there's not a lot of instantaneous falling apart that's going to happen...
Member Since: November 8, 2009 Posts: 4 Comments: 13549
839. pottery
1:47 AM GMT on September 07, 2010
Quoting thelmores:


35-36F?

Pottery, I thought you lived in the Caribbean not the North Pole! LOL

AAAKKK!!!
You got me!!
85-86 F
GOM 87F
(sorry 'bout that!)
Member Since: October 24, 2005 Posts: 0 Comments: 24382
838. stormwatcherCI
1:47 AM GMT on September 07, 2010
Quoting want2lrn:
Post 754, anyone? please.........
I might not be the best one to answer this but as far as I can remember that is what StormW and MH09 have said on here.
Member Since: October 9, 2008 Posts: 0 Comments: 8392
837. leo305
1:46 AM GMT on September 07, 2010
rain isn't warm anymore, at least here in miami.. when it rains it's a cold rain, and it's strange to say the least
Member Since: April 17, 2010 Posts: 0 Comments: 1753

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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.