Intensifying Hermine closes in on the Texas/Mexico coast

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

Share this Blog
1
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 1486 - 1436

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34Blog Index

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%
Member Since: Posts: Comments:
1485. 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.
Member Since: Posts: Comments:
Good morning from St. Maarten. We are feeling the effects of xGaston this morning. Heavy clouds and rain on and off. Not much if any wind to speak of thus far. Our live camera is up and running if you want to take a look.

xGaston Live Camera

Enjoy.
Member Since: Posts: Comments:
Quoting MoltenIce:
Zombie Gaston?


Who is Gaston?
Member Since: August 1, 2010 Posts: 0 Comments: 251
Quoting asgolfr999:
eight thirty


Yeah, I was very perplexed why people continued to say it had up to 6 hours over water when it was right by the coast, including the Doc.

Guess the perplexity was right.

(I said around 6pm in the morning - a bit out, not expecting the sudden slowdown by the coast.)
Member Since: Posts: Comments:
eight thirty
Member Since: Posts: Comments:
So, it did make landfall way before midnight.
Member Since: Posts: Comments:
hey guys, i'm in corpus christi, don't know if anyone is still awake, but we are rocking and rolling here right now!
Member Since: Posts: Comments:
Zombie Gaston?
Member Since: Posts: Comments:
Quoting JLPR2:
I'm off to bed, I got tired of seeing the group of clouds Gaston has become, yet it looks slightly better. :\


Night!

eh? Down a millibar? O.o LOL
AL, 09, 2010090706, , BEST, 0, 171N, 610W, 25, 1010, LO


I'm assuming that's Gaston right? I thought it hit the dust...finally.
Member Since: Posts: Comments:
Link Hermine is literally following the highway that Oz is on.
Member Since: Posts: Comments:
1475. calder
Quoting tornadodude:
CycloneOz got stopped at inspection, on the highway, and they had a drug dog. Guess who doesnt and never did have drugs in his vehicle? CycloneOz.


would've been hilarious if he'd had a bit of puff and we saw it online...
Member Since: Posts: Comments:
Quoting tornadodude:
CycloneOz got stopped at inspection, on the highway, and they had a drug dog. Guess who doesnt and never did have drugs in his vehicle? CycloneOz.



Probably assume anyone out in this weather has got to be on drugs right...lol
Member Since: Posts: Comments:
Quoting tornadodude:
CycloneOz got stopped at inspection, on the highway, and they had a drug dog. Guess who doesnt and never did have drugs in his vehicle? CycloneOz.
And the folks at the inspection had a chance to wave. :P
Member Since: Posts: Comments:
CycloneOz got stopped at inspection, on the highway, and they had a drug dog. Guess who doesnt and never did have drugs in his vehicle? CycloneOz.
Member Since: Posts: Comments:
The video gets choppy when he stopped.
Member Since: Posts: Comments:
Quoting GBguy88:
09/07/2010 0139 am

Raymondville, Willacy County.

Tropical storm, reported by law enforcement.


Update to previous report of roof collapse. Roof was
blown off of hotel adjacent to Texas Bar and grill.
Additional roof blown off of John deere implement
dealership. Reports of windows blown out with some
injuries reported from flying glass. Unknown at this time
how many injuries.


Wow!!
Member Since: Posts: Comments:
1469. KC2NOLA
I can see the trees
Member Since: Posts: Comments:
1468. GBguy88
09/07/2010 0139 am

Raymondville, Willacy County.

Tropical storm, reported by law enforcement.


Update to previous report of roof collapse. Roof was
blown off of hotel adjacent to Texas Bar and grill.
Additional roof blown off of John deere implement
dealership. Reports of windows blown out with some
injuries reported from flying glass. Unknown at this time
how many injuries.
Member Since: Posts: Comments:
1466. JLPR2
I'm off to bed, I got tired of seeing the group of clouds Gaston has become, yet it looks slightly better. :\


Night!

eh? Down a millibar? O.o LOL
AL, 09, 2010090706, , BEST, 0, 171N, 610W, 25, 1010, LO
Member Since: Posts: Comments:
1465. xcool
Sep 07 02:00 CDT 14.44 83.1 32.9 39.8
Member Since: Posts: Comments:
Quoting MoltenIce:
How can a tropical system intensify overland?


look up tropical storm Erin, 2007
Member Since: Posts: Comments:
1463. xcool
bye all work at 900am
Member Since: Posts: Comments:
Quoting CoopNTexas:
WOW...Lavergne & Shirley...Bonnie & Clyde...Laurel & Hardy...Batman & Robin



You forgot Lenny & Squiggy!

...btw, the GFS gas been a lot more aggressive with the 9/15 WATL troff...won't budge!
Member Since: Posts: Comments:
How can a tropical system intensify overland?
Member Since: Posts: Comments:
Dudes insane!
Member Since: Posts: Comments:
it was pretty much inline with the NWS readings
Member Since: Posts: Comments:
Handheld device...not sure how well calibrated.
Member Since: Posts: Comments:
Wow some dude driving in the middle of a TS in the Cyclone Oz live feed.
Member Since: Posts: Comments:
Oz is in the thick of it!
Member Since: Posts: Comments:
Quoting PensacolaDoug:
OZ REPORTS 992 MILLIBARS IN THE EYEWALL


Is it Strenthening??
Member Since: Posts: Comments:
1454. mbjjm
The NHC might have to upgrade this storm to a hurricane in its post storm season anaylsis, aslo Earl went it hit Canada as a "tropical storm" so places had hurricane conditions
Member Since: Posts: Comments:
OZ REPORTS 992 MILLIBARS IN THE EYEWALL
Member Since: Posts: Comments:
1452. GBguy88
"Most newly planted trees and shrubs will be damaged or uprooted.
Some rotting small trees will be uprooted... and rotten large
branches will snap. Numerous small limbs will separate from trees.
Several Palm fronds will be blown down."

...It's all fun and games until somebody loses a palm frond.
Member Since: Posts: Comments:
1451. xcool
CoopNTexas take care ;)
Member Since: Posts: Comments:
1450. JLPR2
Quoting CoopNTexas:
WOW...Lavergne & Shirley...Bonnie & Clyde...Laurel & Hardy...Batman & Robin



Two hurricanes in the CATL and a TS in the Caribbean, looks like active times are ahead. XD
Member Since: Posts: Comments:
1449. xcool


Member Since: Posts: Comments:
bedtime...long nights ahead of those verify!

Hope not coolio.
Member Since: Posts: Comments:
Quoting xcool:
CoopNTexas gom open


LEAVE the GOM alone please!!
Member Since: Posts: Comments:
1446. xcool
CoopNTexas gom open
Member Since: Posts: Comments:
WOW...Lavergne & Shirley...Bonnie & Clyde...Laurel & Hardy...Batman & Robin

Member Since: Posts: Comments:
Wow, glad I don't trust models past 3 -5 days.
Member Since: Posts: Comments:
1443. JLPR2
Quoting CoopNTexas:


Ah dang, heading west towards the islands, that's no good. :\ The ants are going to freak out! XD
Member Since: Posts: Comments:
1441. xcool
CoopNTexas yeah.i know later w'e getting in September systems like to stay west
Member Since: Posts: Comments:
Quoting GBguy88:


Where were you at during Ivan, just out of curiosity? I was at the west end of Gulf Breeze, Florida.


Sorry....Had to do my job......I was just southeast of Marianna......where the Supertornado touched down
Member Since: Posts: Comments:
Quoting JLPR2:


Impressive looking system even inland.


yeah, he recorded a pressure reading of 988 mb in raymondville
Member Since: Posts: Comments:
Member Since: Posts: Comments:
1437. GBguy88
Storm report in Harlingen says a peak wind gust of 72mph was reported. Quite impressive for a storm that popped up over night.
Member Since: Posts: Comments:
1436. JLPR2
Quoting tornadodude:


he is in raymondville, heading back north


Impressive looking system even inland.
Member Since: Posts: Comments:

Viewing: 1486 - 1436

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34Blog Index

Top of Page

About JeffMasters

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.