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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800 TWO. Will be a TD again or needs to be. 30-35 sustained and 40gusts
will be a mess and right now it looks lime no one is taking it seriously
here except the more cuatious people. And gaston is only going to get stronger
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How strong will Hermine be at her next update?

A. 60 mph TS
B. 65 mph TS
C. 70 mph TS
D. 75 mph HUrricane

I vote C.
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Quoting Krycek1984:


People have to be reminded of this at least once a day it seems and it's sad...a wobble does not mean there is a change in overall direction. Time will tell if it is indeed going to move NE as a trend but most likely not, it's probably just a wobble.


I agree with you that a wobble does not mean a change in direction, but in this case it can mean Hermine being over water another 1-2 hours longer than forecast and possibly being stronger.'

In that instance it does make a difference
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You know even though I said ex gaston looks to have one foot in the grave and the other one sliding, these types of systems can be potentially dangerous if everything comes together for them, they are fighters and don't count out a fighter until their gone.,JMO
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Quoting thunderblogger:
Donde Matamoros????


Matamoros es sur de Brownsville, TX
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300 thunderblogger "Donde Matamoros????"

On the Mexican side of the border from Brownsville,Texas.
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Quoting futuremet:
This is the Caribbean in two days:


Is he going to make it?
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In two hours Hermine seems to have moved roughly 10nm at a heading of ~340 degrees.
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MATAMOROS
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Quoting weatherman12345:
POLL TIME!
Ex Gaston at the 8:00PM TWO
A. 50%
B. 60%
C. 70%
D. 80%
E. 90%


You forgot the 20% and 30% option..... LOL
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Quoting TXCaneCrasher:


please tell me what storms you have seen so many times do this. I live on the middle TX coast and really don't remember this happening. Please tell me


Hurricane Edith in 1971 is the best example of this.
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321. iahwx
Quoting 7544:
could the front be pushing hermine ne hmm


Does seem to be some NE motion but I'd guess a wobble. Seems unlikely she'd change direction and head NE now for very long anyway.
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Quoting thunderblogger:
Donde Matamoros????
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Quoting Levi32:
Here we go with the frictional effects keeping Hermine offshore and moving more northerly for the moment. This is how storms like Dolly in 2008 snuck into Texas even though they were bound for Mexico. Now this is too close to avoid Mexico now, but it is trying to stay over water and come farther north.

That really is amazing to watch.
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Evening folks,

Popping back in after the summer holidays. I was just going to check on the steering currents for Hermine and the remnants of Gaston when I got the message "no data available for winds" for both the latest and -3hrs for all steering layers on the CIMSS Steering currents site.
Do you get the same? And does anyone know another page with steering currents? TIA, I'd appreciate it greately.

Stay safe at the MX/TX border, I hope that after making landfall Hermine moves fast over TX towards the north so that flooding won't be too bad. I'm praying for stronger steering currents than those I see on the -6h images. A wet system like this is no good when moving slow.
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Quoting dmaddox:
YES!


People have to be reminded of this at least once a day it seems and it's sad...a wobble does not mean there is a change in overall direction. Time will tell if it is indeed going to move NE as a trend but most likely not, it's probably just a wobble.
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I think the high over the W Gulf has weakened just a tiny bit. That along with friction from land is probably slowing the storm down a bit. I don't think we're lookin at any drastic track changes. May mean the difference between TX and MX tho.
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314. JLPR2
Quoting Relix:
Heh, Gaston is looking worse now. What a sad system. Oh well.


Shh! Don't say anything till he is off our area. XD
Member Since: September 4, 2007 Posts: 7 Comments: 8506
Quoting TXCaneCrasher:


please tell me what storms you have seen so many times do this. I live on the middle TX coast and really don't remember this happening. Please tell me


Back in the 19th and early 20th centuries there are storms in the database that rode alone the gulf coast of Texas. I find those suspect since it seems to have no happened in the "modern era," at least so far as I have seen
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Quoting evandeck:


Is it me or does it looks like it's moving NNE or NE?
YES!
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Quoting WeatherNerdPR:

Nuevo Leon (The Mexican State were Monterrey is) had 1.35 billion dollars in damage. They got hammered.


Yes and the Santa Catarina river which passes through the city destroyed bridges and sports infrastructure placed near the river. And also, what surprises me is that the Santa Catarina has still a flow and Alex happened more than 2 months ago!! Even with the hard rainfall last friday and saturday, the Santa Catarina river expanded and it covers all the river bed as of now. Let's hope with Hermine that more flooding rain is avoided.
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310. 7544
could the front be pushing hermine ne hmm
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309. Relix
Heh, Gaston is looking worse now. What a sad system. Oh well.
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Quoting Levi32:
Here we go with the frictional effects keeping Hermine offshore and moving more northerly for the moment. This is how storms like Dolly in 2008 snuck into Texas even though they were bound for Mexico. Now this is too close to avoid Mexico now, but it is trying to stay over water and come farther north.



Is it me or does it looks like it's moving NNE or NE?
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Donde Matamoros????
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it just took a NNE jog!!!
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AOI

AOI

AOI

AOI

AOI

AOI


TS BUSTED FORECAST ALIBI
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Quoting Stormchaser2007:


It would have to be under ideal conditions.


Yeah.
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Quoting ozzyman236:
this could be what i have been talking about all along the steering currents in that part of the gulf when a storm is moving in a northerly component spells trouble for the whole texas coast...i seen it happen to many times...houston pay very close attention..


please tell me what storms you have seen so many times do this. I live on the middle TX coast and really don't remember this happening. Please tell me
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Quoting Stormchaser2007:


It would have to be under ideal conditions.


yea, but I don't recall wilma under perfect conditions though, I remember there was some shear around the center, but it just DMAX'd to the max
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Quoting futuremet:
This is the Caribbean in two days:




Rut-Roh
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Quoting 7544:


is that mess moving south tia ?
The one to the north of Miami, yes. The one over the Gulf stream is headed towards the west. Very intense lightning by where I'm at because of this thunderstorm just north of me.

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Quoting weatherman12345:
POLL TIME!
Ex Gaston at the 8:00PM TWO
A. 50%
B. 60%
C. 70%
D. 80%
E. 90%
C
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Quoting TropicalAnalystwx13:
If something can move over that TCHP slowly, I'm willing to bet that it would rival Wilma's intensity. Especially if it was already a Hurricane.



It would have to be under ideal conditions.
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294. 7544
Quoting sammywammybamy:
Does Anyone else see just a little NE Jog at the Very End of that Radar Loop of Hermine?


yeap i do
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Pressure at Port Isabel continues to drop, so either Hermine is drifting N, or deepening, or both.
Member Since: August 29, 2010 Posts: 0 Comments: 5236
Levi or Storm,

Isn't possible she slowed cause of the low over Minnisota? Kinda felt some effect as it pulled the high northward, or am I just dumb!
I am not saying it will pull her north just that she felt it for a little bit.
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Quoting KanKunKid:


Looks like it will get Matamoros pretty good!


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290. 7544
Quoting MiamiHurricanes09:
Ouch, some nasty thunderstorm activity headed my way over here. Loads of thunder and lightning all over the place.



is that mess moving south tia ?
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Quoting sammywammybamy:
Whats Going On Over Florida?


Wondering that myself. Tail end of the newly shortened front. Interesting. Hope to hear some input from the more well-versed bloggers at some point. Good evening.
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Levi: How far north? Tx/Mx border?
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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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