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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Quoting Cotillion:


Morning! Can't remember the last time I had coffee.


Sorry, Cotillion - I'd put tea out, but mine is always too strong for most to drink - kind of like my "Navy" coffee, LOL.
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I am amazed at how much dry air and SAL is around the area. comming from 2 different areas the GOMEX getting dry air from the Conus and the atlantic getting it from the sahara, but the ammount of dry air is enormous I think that will calm things down alot. Anyway temperatures here have been cooler and dryer than normal again another year with an early fall I guess.
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Link

Ike I think I see your avatar in this video, anyways GFS shows another long range threat with the ECMWF.
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Quoting CoopsWife:
Morning, Ike, Cotillion, et al.

Running late today - first day of EllieRose's senior year, LOL. Coffee, juice and french toast on the sideboard.

Atlantic is not looking bad for this time of year, but I doubt Mexico needed any more rain...


Morning! Can't remember the last time I had coffee.
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1531. Patrap
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1530. Patrap
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Morning Surf - been daybreak here for quite a while, LOL.
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1528. Patrap
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1527. surfmom
Good Morning Fans of Daybreak
Sipping Java & scouting out what Hermine is up to....
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Quoting IKE:


Not based on what the models are showing.

Brownsville,TX. airport...peak wind gust from Hermine...Max Gust Speed 69 mph


I actually disagree.

Looking at the Euro, it keeps Igor as a TS or so before intensifying it up by the islands a la Earl. GFS doesn't really bomb it that much (a stark difference to Danielle).

I can't think shear would be too much of a problem, so I'd assume it'd be dry air keeping it in check.
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Quoting IKE:


Not based on what the models are showing.

Brownsville,TX. airport...peak wind gust from Hermine...Max Gust Speed 69 mph


I saw the models but if you take a look to the dry air map you will see that the dry air in its way is very intense. Let see what happens.

Take Care
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Of course, yet another season that makes you think:

How many seasons before satellite would have picked up on a Bonnie, a Colin, a Gaston? Gaston would be very unlikely.

2009: Grace wouldn't have been named. Erika? Henri? Take those 3 storms out and you get 6-3-2.

2008: Arthur. Nana, for sure. Marco. Laura. Josephine. All 5 storms might not have been named a few years ago. What does that leave us? 11-8-5.

2007: Andrea wouldn't have been, it was subtropical. Barry, possibly. Chantal might not have been. Not Jerry. Erin might've been missed, it was over in a flash. Melissa probably not. Say keeping Barry and Erin at least, you still only get 11-6-2.

Not to say that these shouldn't have been named - they should. However, you look at it in a historical perspective with a 're-adjusted' number and many of those seasons would not look out of place in years gone-by.

Further proving why the 10-6-2 climatology average is nonsense (nonsense without due clarification and balancing).
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Looks as if Corpus to Kingsville and up to Victoria is getting the worst of it at the moment
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1522. IKE
SYNOPSIS FOR CARIBBEAN SEA AND TROPICAL N ATLC FROM 07N TO 22N
BETWEEN 55W AND 65W
530 AM EDT TUE SEP 07 2010

.SYNOPSIS...THE REMNANT LOW PRES OF GASTON NEAR 17N60W 1010 MB
WILL CONTINUE TO WEAKEN WHILE MOVING WESTWARD ACROSS THE
NORTHERN CARIBBEAN PASSING S OF PUERTO RICO WED...S OF
HISPANIOLA WED NIGHT THROUGH FRI AND S OF JAMAICA FRI INTO SAT.
A LOW LEVEL TROUGH N OF 18N ALONG 75W WILL MOVE SLOWLY W
REACHING THE YUCATAN CHANNEL SAT.
...........................................

SYNOPSIS FOR THE GULF OF MEXICO
430 AM CDT TUE SEP 07 2010

.SYNOPSIS...THE CENTER TROPICAL STORM HERMINE INLAND AT 27.0N
98.0W AT 4 AM CDT 993 MB MOVING N NW OR 340 DEG AT 15 KT.
MAXIMUM SUSTAINED WINDS 45 KT GUSTS 55 KT OVER WATER WITH
WARNINGS SHIFTING INLAND BY NOON TODAY. HERMINE IS FORECAST TO
WEAKEN AS IT CONTINUES INLAND ACROSS FAR NE MEXICO TO S TEXAS
NEAR 28.7N 99.0W THIS AFTERNOON AND DIMINISH TO A TROPICAL
DEPRESSION NEAR 30.9N 100.1W TONIGHT...FURTHER WEAKEN TO A
REMNANT LOW NEAR 33.3N 100.2W WED. HIGH PRES WILL BUILD ACROSS
THE GULF WATERS TONIGHT THROUGH SAT. A WEAK TROUGH WILL DRIFT W
THROUGH THE FLORIDA STRAITS THU NIGHT THROUGH SAT.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
im surprised the circulation of Hermine is still pretty strong and still has an eye on radar
Member Since: August 1, 2006 Posts: 28 Comments: 3716
Morning, Ike, Cotillion, et al.

Running late today - first day of EllieRose's senior year, LOL. Coffee, juice and french toast on the sideboard.

Atlantic is not looking bad for this time of year, but I doubt Mexico needed any more rain...
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1519. IKE
Quoting Eugeniopr:


Ike:

Do you think dry air will be a problem for future Igor in the Atlantic?


Not based on what the models are showing.

Brownsville,TX. airport...peak wind gust from Hermine...Max Gust Speed 69 mph
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1518. scott39
Quoting IKE:
Latest GFS in 10 days....Igor heading to the north ATL....

Im starting to think a CV-TC is looking to be less of a threat on the Gulf Coast, as the season moves forward.
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1517. mbjjm
oz now in Hermine's eyewall in Alice,Texas



Live
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Quoting IKE:
Latest GFS in 10 days....Igor heading to the north ATL....



Ike:

Do you think dry air will be a problem for future Igor in the Atlantic?
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The last 3 storms that have made their way into the Caribbean past October have all become hurricanes (not inc the GoM/BoC etc).

Hurricane Ida, 2009.
Hurricane Paloma, 2008.
Hurricane Omar, 2008.

Even in 2007, Noel eventually became a hurricane. Olga sorta got done in by the Hispaniola mountains and never really got to spend time splashing in the water.

This season probably does have at least one more Cape Verde long tracker in it. Igor may end up taking a similar path to Earl or it might not, way too early to tell. A CV hurricane will probably come despite the dry air. Two? We'll see. The CV season still has 3 weeks or so left.

October might not be fun, though.

Anything could pull an Opal, Hilda, Paloma etc.
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1514. IKE
Latest GFS in 10 days....Igor heading to the north ATL....

Member Since: June 9, 2005 Posts: 23 Comments: 37860
hmm a ULH has now developed just to the east of gaston should be over or a little closer to him soon when it happens should help out gastons little problem and the the booming will start
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1512. Keys99
From the National Weather Service Key West

IN 1965...CATEGORY 3 HURRICANE BETSY MOVED WEST ACROSS THE UPPER
KEYS...THROUGH FLORIDA BAY AND NORTH OF THE LOWER KEYS. KEY WEST
MEASURED A PEAK WIND OF 81 MPH AND A MINIMUM PRESSURE OF 29.44" AS
WELL AS STORM TIDE OF 5-7 FT...WHILE BIG PINE EXPERIENCED WINDS OF
125-140 MPH WITH GUSTS TO 165 MPH. IN 1878...A TROPICAL STORM MOVED
NORTH NORTHWEST OFF OF CUBA...CROSSING THE MIDDLE KEYS.
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1511. scott39
Quoting mcluvincane:
What happened 2 the African wave train? Peak of the season nears and it looks like June
Its still there. Models are picking up on a couple potential TCs for this week and next.
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1510. scott39
Quoting portcharlotte:
I agree Scott...it was said that the high would be so dominant without re-curves! Instead since Danielle it's been the theme and I.ve seen this happen before...the weakness never leaves



The high is dominant right now,although Pre-Igor feels the weakness on most models at about 60W.Its almost like the high is moving out of the way for these majors to re-curve,and then a trough is coming in to kick it.
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What happened 2 the African wave train? Peak of the season nears and it looks like June
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Interesting difference between the 06z GFS and the 00z Euro on the 2nd wave.

The GFS wants to make it a Gaston, basically falling apart not long after forming.

The Euro wants it to pull a Fred and get strong, fast.
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Quoting cctxshirl:

In Rockport here, it's raining (which we definitely need) and nothing more. Looks like Hermine went in near Brownsville.
I'll say it again--if this is all S. TX gets this season, we'll take it--these winds are winds we see a lot of times on just windy days! I know Mexico doesn't need the flooding since they just went through all that flooding with Alex in June, but a TS is definitely a lot better than what we could get.
Could have been so much worse! I am sure glad we mowed on Sunday-no telling how long it's gonna take to dry out here
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Any long range threats to the conus we may have 2 worry about.. models predict anything?
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I agree Scott...it was said that the high would be so dominant without re-curves! Instead since Danielle it's been the theme and I.ve seen this happen before...the weakness never leaves



Quoting scott39:
Looks like a weakness in the high at 60 longitude, is going to be the theme in the Atlantic this season. What happened to the strong high this season to keep storms from recurving? Hope this continues.
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Quoting txraysfan:
womanmarine-what part of Corpus you from? Am north of you-Victoria county, but close to Port Lavaca

In Rockport here, it's raining (which we definitely need) and nothing more. Looks like Hermine went in near Brownsville.
I'll say it again--if this is all S. TX gets this season, we'll take it--these winds are winds we see a lot of times on just windy days! I know Mexico doesn't need the flooding since they just went through all that flooding with Alex in June, but a TS is definitely a lot better than what we could get.
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sorry if you think I'm insulting you well let me tell you I am not insulting you I know you are smarter so start acting

lol just messn with ya plz don't take it porsanaly

but anyway besides that you under stand the rest of what I said ya
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Quoting aislinnpaps:


They said sustained gusts of 39 miles per hour and tropical storm gusts up to 70? They didn't say anything about damages.
Thanks for the info, am just hoping he's ok
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Quoting txraysfan:
Have a friend in Kingsville, any word on how they are faring?


They said sustained gusts of 39 miles per hour and tropical storm gusts up to 70? They didn't say anything about damages.
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1500. scott39
Quoting wunderkidcayman:
well scott39 if you where smart which by what you said shows otherwise quite the opposite indeed because you and I know well don't know about you but I surly know that it is not dead untill everything is gone the convection the circulation the tracking and the models all gone intensity models still show gaston growing into a hurricane some into a major one too and I would not be surprised if by late tonight or this time 2mrrow we all ready to call it a TD or TS and that will be a lot of crow on the table
Hey whats up with the INSULT??
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With the water temps in the Carib and the GOMEX, anything that gets in there could be scary. : (
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Have a friend in Kingsville, any word on how they are faring?
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well scott39 if you where smart which by what you said shows otherwise quite the opposite indeed because you and I know well don't know about you but I surly know that it is not dead untill everything is gone the convection the circulation the tracking and the models all gone intensity models still show gaston growing into a hurricane some into a major one too and I would not be surprised if by late tonight or this time 2mrrow we all ready to call it a TD or TS and that will be a lot of crow on the table
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It's up to ex-Gaston now.

Shear shouldn't be too much of a problem. There's a small pocket of 15-20kt ahead of him, but that's really it. The ULL etc moving with him which has been an issue for most storms this year, but he's hardly in buzzsaw range.

He has now passed the last of the really dry air.

Waters are warm. Very warm, even in the traditionally hostile East Caribbean.

He's reached the Caribbean, the first system that really has. Yes, Earl just about clipped it, but it was north/east of the Caribbean Sea for the most part.

However, as we all know... just because a storm 'can' doesn't mean that it 'will'.

Anything with a circulation should be watched and monitored closely going into the hydro-powderkeg that is the Caribbean, however.
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womanmarine-what part of Corpus you from? Am north of you-Victoria county, but close to Port Lavaca
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I will be watching to see if they show any photos of Raymondville when it is all over. I used to live and teach there.
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Quoting womanmarine:
hey guys, i'm in corpus christi, don't know if anyone is still awake, but we are rocking and rolling here right now!
Same here-been raining-doesn't look like end in sight yet
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1492. scott39
Quoting aislinnpaps:
Good morning, everyone.
Goodmorning
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1491. scott39
Looks like Igor may live up to his name.
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Good morning, everyone.
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1489. scott39
Quoting HurricaneSwirl:
Ouch, Gaston down to 20% from 50% at 8PM. Hermine still looks impressive especially for being inland for 8 and a half hours. Attention should really be focused on "pre-Igor" and if the ECMWF is right, "pre-Julia".
The ECMWF hasnt done a very good job this year, in forecasting high pressure in the Atlantic.
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Ouch, Gaston down to 20% from 50% at 8PM. Hermine still looks impressive especially for being inland for 8 and a half hours. Attention should really be focused on "pre-Igor" and if the ECMWF is right, "pre-Julia".
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1487. scott39
Quoting wunderkidcayman:
wow now that gaston is in the caribbean you all want to call it dead well let me give you a heads up gaston is not dead and is getting into favorable condition and yes the circulation is poorly define and yes it is short on convection that is organized but that can change between the next 6-24 hours and I think that the NHC has lowered too much right not the least it should be is a 30% or 40%
If it was stronger it might survive the graveyard of the Eastern Carribean. Its dead kid--Let him go.
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wow now that gaston is in the caribbean you all want to call it dead well let me give you a heads up gaston is not dead and is getting into favorable condition and yes the circulation is poorly define and yes it is short on convection that is organized but that can change between the next 6-24 hours and I think that the NHC has lowered too much right not the least it should be is a 30% or 40%
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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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