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 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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looks like recon headed out of XGaston
Member Since: September 19, 2005 Posts: 2 Comments: 4266
Good afternoon! An eye on Hermine? Gaston looks even better than ever today!

Hermine appears to be getting smaller; tightening up. I will not be surprised to hear that this has been upgraded to a hurricane.
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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.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
From radar I see just west of due north, but with low confidence.
Member Since: August 26, 2006 Posts: 16 Comments: 4766


AVN LOOP




Some good "reds" popping now over Gaston's coc. We'll see if he can hang on to them. Position is likely now far enough south of Earl and Fiona's wake that he might finally be getting into some warmer, deeper waters that will allow him to create enough moisture lift faster than the ULL to its west can steal it. ;)
Member Since: July 9, 2006 Posts: 184 Comments: 29610
Quoting houstongator:
Sorry... I meant Hermine, not the band. thank goodness that is moving... my door is leaking...


Oh ok well duck tape works but you all going to get alot of this off and on heavy rains for a couple of days it looks like unless this storm does something stupid and decides to come my way "good luck"
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Quoting CybrTeddy:
992 mb found by recon.

Starting to strengthen more.
What we expected based on Sat and Radar in recent hour.
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Product: Air Force Vortex Message (URNT12 KNHC)
Transmitted: 6th day of the month at 20:33Z
Aircraft: Air Force Aircraft (Last 3 digits of the tail number are 301)
Storm Number & Year: 10L in 2010
Storm Name: Hermine (flight in the North Atlantic basin)
Mission Number: 2
Observation Number: 08
A. Time of Center Fix: 6th day of the month at 20:24:10Z
B. Center Fix Coordinates: 2426'N 9653'W (24.4333N 96.8833W)
B. Center Fix Location: 110 miles (177 km) to the SSE (160) from Brownsville, TX, USA.
C. Minimum Height at Standard Level: 1,358m (4,455ft) at 850mb
D. Estimated (by SFMR or visually) Maximum Surface Wind: 45kts (~ 51.8mph)
E. Location of the Estimated Maximum Surface Wind: 30 nautical miles (35 statute miles) to the SE (129) of center fix
F. Maximum Flight Level Wind Inbound: From 179 at 49kts (From the S at ~ 56.4mph)
G. Location of Maximum Flight Level Wind Inbound: 37 nautical miles (43 statute miles) to the SE (129) of center fix
H. Minimum Sea Level Pressure: 992mb (29.29 inHg) - Extrapolated
I. Maximum Flight Level Temp & Pressure Altitude Outside Eye: 17C (63F) at a pressure alt. of 1,528m (5,013ft)
J. Maximum Flight Level Temp & Pressure Altitude Inside Eye: 21C (70F) at a pressure alt. of 1,527m (5,010ft)
K. Dewpoint Temp (collected at same location as temp inside eye): 18C (64F)
K. Sea Surface Temp (collected at same location as temp inside eye): Not Available
L. Eye Character: Not Available
M. Eye Shape: Not Available
N. Fix Determined By: Penetration, Radar, Wind, Pressure and Temperature
N. Fix Level: 850mb
O. Navigation Fix Accuracy: 0.02 nautical miles
O. Meteorological Accuracy: 1 nautical mile
Remarks Section:
Maximum Flight Level Wind: 49kts (~ 56.4mph) in the southeast quadrant at 20:11:40Z
Sea Level Pressure Extrapolation From: 850mb
Member Since: August 10, 2009 Posts: 0 Comments: 247
992 mb found by recon.

Starting to strengthen more.
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Quoting Hhunter:
62mph winds probably higher coming soon

20:25:30Z 24.500N 96.933W 841.8 mb
(~ 24.86 inHg) 1,472 meters
(~ 4,829 feet) 997.3 mb
(~ 29.45 inHg) - From 84° at 41 knots
(From the E at ~ 47.1 mph) 16.2°C*
(~ 61.2°F*) -* 42 knots
(~ 48.3 mph) 55 knots*
(~ 63.2 mph*) 17 mm/hr*
(~ 0.67 in/hr*) 53.7 knots* (~ 61.7 mph*)
Tropical Storm* 131.0%*


star next to it means its a questionable reading
Member Since: March 10, 2010 Posts: 1 Comments: 7874
Quoting FortBendTX:
831:

Yep, my Church is on Church Street funnily enough :) I did not know there was a fault line though. I will have to look into that!


I no longer remember church it is, and given that this was over a decade ago it is possible the building has had to be abandoned.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting Hhunter:
HECK HERE IN TEXAS WE KNOW GASTON COULD BE OURS ALSO THE WAY THIS YEARS GOING...


I hope not.
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could that front pull hermine nne or ne if hermine slowed down....
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62mph winds probably higher coming soon

20:25:30Z 24.500N 96.933W 841.8 mb
(~ 24.86 inHg) 1,472 meters
(~ 4,829 feet) 997.3 mb
(~ 29.45 inHg) - From 84° at 41 knots
(From the E at ~ 47.1 mph) 16.2°C*
(~ 61.2°F*) -* 42 knots
(~ 48.3 mph) 55 knots*
(~ 63.2 mph*) 17 mm/hr*
(~ 0.67 in/hr*) 53.7 knots* (~ 61.7 mph*)
Tropical Storm* 131.0%*
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Too bad the Weather Channel did not send anyone out to do live shots. They had all day today, but I guess not.
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831:

Yep, my Church is on Church Street funnily enough :) I did not know there was a fault line though. I will have to look into that!
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Quoting Skyepony:
Hermine maybe feeling the land, tightening up. May see it roll more north & try & stay off land a bit. Wouldn't be surprised if one of those coves at the very north end of MX end up with the landfall.


I've definitely seen storms do that before. Is there a better scientific explanation than that the storm "wants" to stay offshore?
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Quoting poknsnok:


i disagree
I 2nd that. While plenty of dry air N and W, it's just pulling in moist air. Maybe the proximity to land is causing some issues.
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837. xcool
where rob at .
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well its 430 and Hermine still seems to be well away from the coast, now moving NNW

I dont think landfall will be by 5pm or even by sunset, closer to midnight
Member Since: March 10, 2010 Posts: 1 Comments: 7874
992mb

20:24:00Z 24.433N 96.883W 842.4 mb
(~ 24.88 inHg) 1,438 meters
(~ 4,718 feet) 992.0 mb
(~ 29.29 inHg) - From 246° at 3 knots
(From the WSW at ~ 3.4 mph) 20.3°C
(~ 68.5°F) 18.1°C
(~ 64.6°F) 5 knots
(~ 5.8 mph) 30 knots*
(~ 34.5 mph*) 7 mm/hr*
(~ 0.28 in/hr*) 18.0 knots* (~ 20.7 mph*)
600.0%
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Quoting poknsnok:


i disagree


You may disagree...but the radar doesn't. ;-) Hermine looks to be pulling out of the temporary dive, though, so the point may be moot shortly...
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Time: 20:24:00Z
Coordinates: 24.4333N 96.8833W
Acft. Static Air Press: 842.4 mb (~ 24.88 inHg)
Acft. Geopotential Hgt: 1,438 meters (~ 4,718 feet)
Extrap. Sfc. Press: 992.0 mb (~ 29.29 inHg)
Member Since: August 10, 2009 Posts: 0 Comments: 247
832. Skyepony (Mod)
Hermine maybe feeling the land, tightening up. May see it roll more north & try & stay off land a bit. Wouldn't be surprised if one of those coves at the very north end of MX end up with the landfall.
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Quoting FortBendTX:
821:

Down in Southern Ft. Bend County (Needville)


Needville? Took a sidetrip in college on a field trip to look at the Needville Fault where it goes through one of the churches on the aptly named Church Street.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
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Quoting blsealevel:




nope still moving
Sorry... I meant Hermine, not the band. thank goodness that is moving... my door is leaking...
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828. 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?
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827. xcool
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Quoting Hhunter:


guess you need to stay alert and search the archive my good chap


I guess so. Better get a cup of joe and try again.
Member Since: August 10, 2009 Posts: 0 Comments: 247
Corpus here, in a clear spot, the sun has even peeked out. Nice band heading this way and it looks pretty wicked.
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821:

Down in Southern Ft. Bend County (Needville)
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Quoting Neapolitan:
It appears from radar out of Brownsville that some dry air has made its way into Hermine's heart; over the past half-hour, the once-developing eye has become disrupted and slightly elongtated, with a fairly large clear slot to the northwest. Convection looks impressive on satellite, though that's delayed longer than the radar, so we'll have to see what happens...


i disagree
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812:

I am glad I am not the only one who saw that. I hope it is temporary too. Don't want her out in this 86 degree water much longer...
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FortBend TX: what part? Hwy 6 and Ft. Bend Toll Road here.
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I've got to admit.. 3 hours ago.. the thing didn't even have an eye
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I am amazed with Hermine. The gulf is clearly a primed powder keg that is just waiting for the slightest provocation to blow.
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Bands of heavy rain have been moving through Katy, TX.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Wow I go run errands and come back to an eye on radar.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting houstongator:
Nice band just came through Cypress, TX (NorthWest of Houston). We have had almost two inches today and gusts of up to 20 mph. I was looking closely at the radar and the storm looks almost stationary for the last 30 minutes. Anyone else notice that?




nope still moving
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Quoting houstongator:
Nice band just came through Cypress, TX (NorthWest of Houston). We have had almost two inches today and gusts of up to 20 mph. I was looking closely at the radar and the storm looks almost stationary for the last 30 minutes. Anyone else notice that?


Just east of you..We actually have lost power a couple of times today. Looking at Brownsville Radar I think we are just looking at a wobble. ( I hope)
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Those Mexican barrier island are getting lashed. Does anyone know if there are appreciable populations out there?
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It appears from radar out of Brownsville that some dry air has made its way into Hermine's heart; over the past half-hour, the once-developing eye has become disrupted and slightly elongtated, with a fairly large clear slot to the northwest. Convection looks impressive on satellite, though that's delayed longer than the radar, so we'll have to see what happens...
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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!
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Nice band just came through Cypress, TX (NorthWest of Houston). We have had almost two inches today and gusts of up to 20 mph. I was looking closely at the radar and the storm looks almost stationary for the last 30 minutes. Anyone else notice that?
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Quoting scott39:
Its hard to tell that there is a West component to the motion.


very hard to see looks generally N motion to me
for now anyway.
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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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