Hurricane watches for Mexico and Texas as Hermine suddenly develops

By: Dr. Jeff Masters , 4:15 PM GMT on September 06, 2010

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Hurricane watches are up for the Texas/Mexico border region as fast developing Tropical Storm Hermine steams towards the coast at 13 mph. Hermine was a tropical depression twelve hours ago, got its name just six hours ago, but already is a threat to intensify into a hurricane by tonight. It's remarkable how fast Gulf of Mexico disturbances can blow up into strong tropical storms, when the right mix of warm waters and low wind shear develops. Indeed, water temperatures are a very warm 30°C, wind shear is a low 5 - 10 knots, and the atmosphere is very moist in the Gulf--ideal conditions for a tropical storm. 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 moved ashore over southern Texas and northern Mexico, with radar estimated rainfall amounts already exceeding two inches in a few areas along the coast. Radar loops show that an eyewall may be beginning to form, and I expect this process will continue through the afternoon and early evening. Satellite imagery shows that Hermine is getting more organized, with vigorous thunderstorms with very cold tops building, low-level spiral bands developing, and improving upper-level outflow occurring on all sides except the west. There is some dry air to the west of Hermine over land that is restricting the storm's development there.

Forecast for Hermine
Hermine doesn't have much time over water before it comes ashore, which is a good thing. Hermine is organizing rapidly, and has a shot at reaching hurricane strength before the center moves ashore late tonight, near midnight. Neither the GFDL or HWRF models develop Hermine into a hurricane, but the HWRF model does predict that tropical storm force winds of 39+ mph will affect the coast as far north as Corpus Christi, Texas. 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. Early afternoon radar image of Tropical Storm Hermine.

Gaston continues to suffer from dry air
The remains of Tropical Storm 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 late this afternoon and continuing into the night. A pass from the ASCAT satellite this morning at 9:03 am EDT showed a large region of 25 mph winds on the north side of Gaston's circulation, and these winds will move into the northern Lesser Antilles late this afternoon. 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. Gaston does have developed a well-organized surface circulation, but not enough heavy thunderstorm activity to be considered a tropical depression. A large amount of dry air surrounds Gaston's remains on all sides, as seen on water vapor satellite loops.


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

Forecast for Gaston
Dry air will continue to be the major impediment to development for Gaston, 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 it 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. The models don't give much support for Gaston surviving past Wednesday, since many of them have the storm hitting the rugged island of Hispaniola, disrupting the storm.

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, the Turks and Caicos Islands, and Jamaica Wednesday night and Thursday morning. Though none of the global dynamical computer models are showing this, should Gaston survive the dry air and its coming encounter with Hispaniola, the storm will find itself in a very favorable environment for development in the Western Caribbean late in the week, and could intensify into a hurricane by next weekend.

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, and let's hope it doesn't live up to its fearsome-sounding name!

Next post
There will be an update by early this evening.

Jeff Masters

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Quoting ozzyman236:
people in houston should not let there guard down hermine could end up parelling the texas coast and move more north towards the upper texas coast...


I doubt it...
Member Since: July 2, 2009 Posts: 0 Comments: 2811
If you look at the radar out of Brownsville, it seems Hermine moves NW at the beginning of the loops but then goes mostly north at the end
Member Since: March 10, 2010 Posts: 1 Comments: 7813
Hermine's core is REALLY tightening up on radar.
Member Since: July 8, 2005 Posts: 259 Comments: 24154
Houston...

THERE IS A SMALL CHANCE OF SEEING ISOLATED TORNADOES TONIGHT AND
TOMORROW AS RAINBANDS COME ONSHORE ACROSS COASTAL SW AREAS. THIS
THREAT IS GENERALLY SW OF A FREEPORT TO WHARTON TO COLUMBUS LINE.
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Hey Guys
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Dvorak is showing rapid intensification.
Member Since: September 27, 2007 Posts: 1 Comments: 21407
896. AtHomeInTX 4:55 PM EDT on September 06, 2010

uh hu they have worked very well so far :-)
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To me Hermine looks like a landfall north of Brownsville, or clipping Brownsville then back over water for a short period before a second landfall just south of Corpus Christi, because of the curvature of the coast. Should her current direction remain unchanged, a lot of northerly component to her right now. Just my thoughts...
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Quoting will40:
Hey Stef did ya get what i sent back to ya?


Hi Will. Yes! Thank you! That thing is amazing! SmileyCentral.com
And between the two of us it's getting quite a work out. Lol.
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Quoting Sfloridacat5:
Hermine looks to only be a few hours from landfall.


Landfall is to be TX or Mexico?
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Quoting angiest:


I looked at the radar this morning, saw the first band heading my way, and ran outand got the yard mowed. Tomorrow should be inspection day for my HOA.


Luckily I do not have an HOA where I live. But I hope yours has fun out in the weather tomorrow! :)
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Quoting cchsweatherman:
Really surprised there hasn't been a Tornado Watch issued for SE Texas yet. Gonna be watching that band approaching Brownsville and Corpus Christi very closely. Seems like there could be some weak rotation in the storms within the band.


SPC updated the Day 1 outlook an hour or so ago but no S TX Mesoscale Discussion issued yet...

SEVERE THREAT WILL CONTINUE TO INCREASE ALONG THE LOWER AND MIDDLE
TX COAST
AS THE CENTER OF HERMINE LIFTS NNWWD TOWARD BRO.
OUTER-MOST BANDS OF STRONG CONVECTION ARE BEGINNING TO ROTATE INTO
DEEP SOUTH TX AND ISOLATED SUPERCELLS SHOULD BECOME MORE COMMON INTO
THE OVERNIGHT HOURS
. HAVE ADJUSTED THE RISK OF ISOLATED TORNADOES
WWD TO INCLUDE MORE OF COASTAL SOUTH TX.

..DARROW.. 09/06/2010
Member Since: April 29, 2006 Posts: 154 Comments: 18710
Quoting MiamiHurricanes09:
Based on the data I'm recieving from Recon along with the distance the circulation has from land, Hermine will likely make landfall as a minimal category 1 hurricane.


Undoubtedly true...
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Quoting Sfloridacat5:
TWC just said its hard to find the center of Hermine? I guess they don't have access to radar?



looks like she has a bead on Mexico
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Hermine looks to only be a few hours from landfall.
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TWC just said its hard to find the center of Hermine? I guess they don't have access to radar?

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Quoting wunderkidcayman:
Gaston is nowhere near dead so people stop saying that according to the NHC 24-72 hours forecasy has gaston moving WSW very soon and will be a big problem in a few days
Actually Gaston will head WNW.
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Quoting FortBendTX:


Yeah, it is nice. I am glad I was able to get my lawn mowed right before it hit!


I looked at the radar this morning, saw the first band heading my way, and ran outand got the yard mowed. Tomorrow should be inspection day for my HOA.
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Quoting xcool:
HERMINE -German, French


Yah Vol
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883. HCW
[B][COLOR=DarkRed]SPC has a 5% Tornado chance for South Texas

[/COLOR][/B][QUOTE] ...MIDDLE TX COAST TONIGHT...
TROPICAL STORM HERMINE IS FORECAST TO APPROACH HURRICANE STRENGTH
JUST PRIOR TO LANDFALL ALONG THE LOWER TX COAST LATE TONIGHT /SEE
LATEST NHC ADVISORIES FOR DETAILS/. DEEPENING OF THE CYCLONE WILL
RESULT IN A CORRIDOR OF INCREASING LOW-LEVEL FLOW/SHEAR TO THE RIGHT
OF THE CYCLONE CENTER...WHICH WILL OVERSPREAD THE MIDDLE TX COAST
OVERNIGHT. THE CORRIDOR OF INCREASING LOW-LEVEL SHEAR WILL ALSO
COINCIDE WITH MID-UPPER 70S BOUNDARY LAYER DEWPOINTS AND AT LEAST
WEAK SURFACE-BASED INSTABILITY. GIVEN THESE ENVIRONMENTAL
FACTORS...WILL INTRODUCE A SLIGHT RISK AND 5% TORNADO PROBABILITIES
FOR OUTER BAND SUPERCELLS DURING THE OVERNIGHT PERIOD.

[/QUOTE]

[IMG]http://www.spc.noaa.gov/products/outlook/day1probotlk_2000_torn.gif[/IMG]
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models????gfdl has gus cat 2.
hmrf make gus a summer shower???????????
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881. xcool
HERMINE -German, French
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Quoting PtownBryan:


Howdy FB! Pearland here! Nice rain huh?


Yeah, it is nice. I am glad I was able to get my lawn mowed right before it hit!
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Quoting Sfloridacat5:


the scary thing is, that it may be trying to develop a tight small eye, if that band wraps around the center.. rapid intensification isn't out of the question especially once the sun goes down
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umm Vero1 have no idea what you are talking about but gaston COC is where the red spot is.
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Quoting dader:
Centex the reason people seem more intersted in Gaston is:
1. This blog is heavily populated by Ecoasters- esp Floridians.
2. People are more interested in major hurricanes not mild tropical storms.
3. The area except Brownsville is not heavily populated and needs the rain.
4. We know where its going- that's part of the fun is hearing ppl guess.

Btw when was the last time a team from Texas won the BCS or did anything in the NFL playoffs?
Plus besides Floridians,there are people more interested in Gaston's potential threat. Hermine, is of your concern, we wish you the best. For us here in the northern caribbean we are worry about Gaston's whereabouts, specially when we still dealing with problems left by the path of major hurricane Earl, last week.
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The classic form...Link
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Quoting FortBendTX:
afternoon all...is there a weakness in the steering currents showing up with Hermine? looks like she is going NNE or NE for the last hour looking at Brownsville radar.

Thanks!


Howdy FB! Pearland here! Nice rain huh?
Member Since: July 5, 2010 Posts: 0 Comments: 170
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Hey Stef did ya get what i sent back to ya?
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wishcasting.....observation is key, the truth is probably something in between.

Quoting wunderkidcayman:
Gaston is nowhere near dead so people stop saying that according to the NHC 24-72 hours forecasy has gaston moving WSW very soon and will be a big problem in a few days
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870. xcool
POOR rob meaing no power for him.
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Best zinger of the day! Subtle but effective

Quoting Hhunter:
Hurricanes101*
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Quoting hurricanemaniac123:
...HERMINE NEARING THE COAST...SHOULD MAKE LANDFALL TONIGHT...

4:00 PM CDT Mon Sep 6
Location: 24.5°N 97.0°W
Max sustained: 60 mph
Moving: NNW at 15 mph
Min pressure: 992 mb



Definately a night time landfall near Brownsville.
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Gaston is nowhere near dead so people stop saying that according to the NHC 24-72 hours forecasy has gaston moving WSW very soon and will be a big problem in a few days
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Quoting BreadandCircuses:




You're kidding right?
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865. Vero1
It looks like Gaston is starting to separate from Gastonette.

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Quoting MiamiHurricanes09:
Based on the data I'm recieving from Recon along with the distance the circulation has from land, Hermine will likely make landfall as a minimal category 1 hurricane.
Maybe, but only because we have plane in system at this critical time.
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recon leaving Ex-Gaston, nothing impressive that I have seen
Member Since: March 10, 2010 Posts: 1 Comments: 7813
...HERMINE NEARING THE COAST...SHOULD MAKE LANDFALL TONIGHT...

4:00 PM CDT Mon Sep 6
Location: 24.5°N 97.0°W
Max sustained: 60 mph
Moving: NNW at 15 mph
Min pressure: 992 mb

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Hurricanes101*
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Quoting BreadandCircuses:



lol
Member Since: July 7, 2010 Posts: 0 Comments: 5690
..HERMINE NEARING THE COAST...SHOULD MAKE LANDFALL TONIGHT...
4:00 PM CDT Mon Sep 6
Location: 24.5°N 97.0°W
Max sustained: 60 mph
Moving: NNW at 15 mph
Min pressure: 992 mb
Member Since: July 8, 2005 Posts: 259 Comments: 24154
Quoting MiamiHurricanes09:
Based on the data I'm recieving from Recon along with the distance the circulation has from land, Hermine will likely make landfall as a minimal category 1 hurricane.


What does the data suggest that Hermine is right now? I have been out, so I haven't gotten a chance to look.
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Quoting dader:
Centex the reason people seem more intersted in Gaston is:
1. This blog is heavily populated by Ecoasters- esp Floridians.
2. People are more interested in major hurricanes not mild tropical storms.
3. The area except Brownsville is not heavily populated and needs the rain.
4. We know where its going- that's part of the fun is hearing ppl guess.

Btw when was the last time a team from Texas won the BCS or did anything in the NFL playoffs?


OUCH! No need to get personal. Lol. Hi everyone.
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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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