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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I am thinking a Mexico landfall but it moves off shore NE of Brownsville and then moves NE across part of the gulf to like Houston area
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Here's the loop that I've been using that shows slow movement.
http://radar.weather.gov/ridge/radar.php?rid=BRO&product=N0R&overlay=11101111&loop=yes
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Quoting TXCaneCrasher:


Cool, it is nice to see some Texans on here. Nice to meet you


Between all of us and some others we got texas covered lol. Where are you San Antonions and Austinites? lol
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recon is heading inbound ... lets see if it has moved at all
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Quoting TXCaneCrasher:


Cool, it is nice to see some Texans on here. Nice to meet you


Between this blog and TexAgs...well it can get pretty entertaining
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looking at GRlevel3 I placed a marker at the lightest DBZ on the radar 1 hour ago and it has moved 2 NM in the last hour so I do agree with the present stall .... I wonder if the high is breaking down fast and we could see it turn N and then NE sooner maybe even over water???
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129. IKE
Landfall is within an hour or 2......

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


Cat 5 to NO?


Houston this time. Pay attention. j/k Lol.
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Quoting houstongator:
Just looking at the zommed in enhanced radar from Accuweather - since we called the low "closed" at around 4:52, the center has not moved... anywhere. It has been stationary.


who you gonna believe? Recon, Radar, or your lyin eyes? LOL
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Quoting TXCaneCrasher:


Oh, sorry for the misunderstanding.


I meant everywhere but after thinking about it I suppose s Texas and especially Mexico are not too happy about it! Sorry yall I'll think next time! lol
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Quoting TexInsAgent:


Oh ok I am in Brazoria


Cool, it is nice to see some Texans on here. Nice to meet you
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Quoting Thundercloud01221991:
Previous Recon Fix 24.6N 97.05W

New Recon Fix 24.65N 97.15W

24.65-24.6 = .05 N

97.15-97.05 = .1 W

WNW just as I said



.05N and .1 West is barely a movement at all, certainly not enough of a movement to prove direction
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Quoting angiest:


Stormtop.


Cat 5 to NO?
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The improving outflow from Hermine has a N component, as shown in Eastern US WV loop.
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Quoting houstongator:
Just looking at the zommed in enhanced radar from Accuweather - since we called the low "closed" at around 4:52, the center has not moved... anywhere. It has been stationary.


I had to go to the NHC radar site to see movement. I did see movement continuing (be it slow) towards the NW.
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Quoting angiest:


Stormtop.
Oh, he doesn't count then. LOL.
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Previous Recon Fix 24.6N 97.05W

New Recon Fix 24.65N 97.15W

24.65-24.6 = .05 N

97.15-97.05 = .1 W

WNW just as I said

Quoting ElConando:


You got you N and W wrong.
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I think that you guys have really overcasting the downcasting to the max with Gaston I am going to watch it tonight and into morning yes Gaston is in the hospital and is starting to come out of critical conditions and you know when that happens they don't look good at first but a few hours or a couple of days later they look really really good so don't let it fool you deathcaster/downcasters and the rest of ya because then ya all become the deatheaters/downeaters of crow and a lot of crow
Member Since: June 13, 2009 Posts: 2 Comments: 12140
I'm mostly a lurker at best so here I go...based on what I've seen/learned here with other similar systems...with Hermine a 60 mph TS right now and looks to be intensify, how in the world could she not at the very least attain Cat 1 strength, with that much time and such warm water? My uneducated guess/prediction is we'll have a lower end CAT 1 that will indeed cause some wind/water dmg in S. Texas. Time will tell..that's for sure!! Back to the shadows......
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Quoting MiamiHurricanes09:
Who has said that Hermine is heading towards the NE?


Stormtop.
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Quoting TXCaneCrasher:


Victoria area


Oh ok I am in Brazoria
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Quoting Thundercloud01221991:
over the past 2 passes it moved .05 N and .1 W.... that is WNW just as I just agreed of not NNW which would have been reveres in the changes.
Just looking at the zommed in enhanced radar from Accuweather - since we called the low "closed" at around 4:52, the center has not moved... anywhere. It has been stationary.
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HH is running quick fixes now




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Quoting ozzyman236:
I SEE LOTS COULD CHANGE THE FORECAST THE STEERING CURRENTS IN THAT PART OF THE GOM ARE ALWAYS WEAK WHEN A STORM HAS A NORTHERLY COMPONENT..HERMINE COULD END UP GOING IN OVER HOUSTON TEXAS PARALLELING THE TEXAS COAST..


keep yer eye on the picture
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Quoting MiamiHurricanes09:
Who has said that Hermine is heading towards the NE?


That one guys thinks he's going to end up in Houston. That's just not going to happen. Hermine will be onshore in Mexico later tonight.
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Quoting Thundercloud01221991:
over the past 2 passes it moved .05 N and .1 W.... that is WNW just as I just agreed of not NNW which would have been reveres in the changes.


You got you N and W wrong.
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Quoting TexInsAgent:
TX Cane....where are you


Victoria area
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Gaston please stop playing with us!
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over the past 2 passes it moved .05 N and .1 W.... that is WNW just as I just agreed of not NNW which would have been reveres in the changes.
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Quoting Sfloridacat5:


I ment Hermine is going to make landfall in Mexico just south of Brownsville. He's definately not going NE like some have mentioned.
Who has said that Hermine is heading towards the NE?
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Quoting angiest:


Bingo.


awww man I only needed 1 more number
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Quoting GeoffreyWPB:


Looks like it's moving a little easterly. Maybe a Fujiwhara dance with Gaston is coming up.:)

That I'd like to see, as long as it turns around and goes straight out into the Atlantic! :)
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Quoting angiest:
Looks like Hermine is slowing to a crawl.


You in Brzoria County too Angiest?
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Quoting btwntx08:

still 30 mi away not there yet


I ment Hermine is going to make landfall in Mexico just south of Brownsville. He's definately not going NE like some have mentioned.
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99. IKE
Quoting Eugeniopr:
2

Ike, Gaston is Asexual. A friend just called from St. Barth and is blowing 12Kt and some soft rain.


Batten down the hatches!
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting PtownBryan:


No need to I kinda rethought my wording and I should have said something different. Sorry s Tx and Mexico we love you!


No worries....take care and enjoy the rain
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Quoting cirrocumulus:
>The study has determined that a local, climatological minimum of tropical
cyclogenesis exists over the eastern Caribbean Sea.



I think that is the third or fourth time of posting. Even wedding banns only require three.
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TX Cane....where are you
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Quoting IKE:
Just a guess....NHC lowers the odds on out-of-Gas-ton?

2

Ike, Gaston is Asexual. A friend just called from St. Barth and is blowing 12Kt and some soft rain.
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Quoting bohonkweatherman:
Is the glass half full or half empty? :)


The problem is the wrong sized glass.
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Quoting thelmores:


negative...... WNW..... certainly not DUE west.......


when I said that they were not exactly at the center yet.. it appeared due west but yes that is WNW... I was just pointing out that this was not moving NNW anymore... a lot of people are talking about NNW when it is clearly turning more westward
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Quoting TXCaneCrasher:


Oh I understand totally, I am just south of you on the coast. I totally misunderstood the post earlier and I apologize to you.


No need to I kinda rethought my wording and I should have said something different. Sorry s Tx and Mexico we love you!
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Quoting CybrTeddy:
Okay thank you for your input StormTop..


Bingo.
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The dry slot located in Hermine's inner core has since filled in with shower and thunderstorm activity.

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Quoting FLdewey:
We need the rain.
We're all going to die

It's going North
It's going West

Look at that moisture
Dry air coming into play

Tastes great
Less filling

Ahhh I love das blogg.
Is the glass half full or half empty? :)
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Okay thank you for your input StormTop..
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Quoting thelmores:


negative...... WNW..... certainly not DUE west.......


I really wonder what people look at when they look at information lol

I think maybe some just chose to see what they want to see lol
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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.

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