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 btwntx08:
guys hermine is more a threat than gaston


thank you
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Quoting btwntx08:
guys hermine is more a threat than gaston
How much rain ya'll had so far?
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I'll go on a limb and say that Recon finds Hurricane Hermine.
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404. flsky
Quoting DarIvy959810:

Gaston will do the samedi as Jeannette did in 2004

Do you mean Jeanne?
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Quoting DarIvy959810:

Gaston will do the samedi as Jeannette did in 2004
REally , Jeanny Cross the Island of Puerto Rico almost a hurricane winds were 73mph with higher gust, it had and eye because it passed over my house, we witness calm for about 20 minutes then the winds shift to the south, it was interesting but caused lot of wind damage to the island.
Member Since: July 31, 2008 Posts: 0 Comments: 730
Hello everybody!

Wanted to introduce myself and say thanks for all of the great inforamtion!

I just discovered this blog a few days ago. Except for the ocassional troll, it seems to be a wealth of information.

Back to lurking.

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And IGOR is born?

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398. IKE
48 hr. ECMWF...

Gaston....

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Quoting doorman79:
Storm,

Got the baby powder ready to do some pimp slapping lol.

What?
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Quoting StormW:


With the change to the NAO, the pattern has to change as well...I'm tellin ya, they're ALL not gonna go out to sea...a CV will most likely come across.

Oh...current 300-850

OK IF he was deep layer system which way would he be moving now ... there is the reflection of the upper low to his west i don"t see a west movement there we would be almost a NNW movement
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Now you all herd the doc.(Let's hope Igor doesn't live up to it's fearsome sounding name)....I told you all......
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Quoting Cotillion:


Correct, the NHC issues watches/warnings for Puerto Rico directly.
not that not correct the National Weather Service on San Juan part of the NOOA in to coordinate on NHC issue the warnings.
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Just took a closer look at some visible satellite imagery for ex-Gaston and I do firmly believe that Hurricane Hunters should definitely find abundant west winds on the southern side of the circulation. If you look closely at the latest visible satellite over ex-Gaston and focus your attention on the southern side, you can definitely see the low cloud motion all towards the west. Even though there's not much cloud cover to go by, its pretty evident that ex-Gaston has maintained a pretty vigorous and well defined circulation. Lets see what it can do as conditions continue to gradually improve.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
Well our wave around 15-16w just moving off the African coastline has been analyzed by the NHC and they mention it in their TWD. So I expect it to be circled tonight or tomorrow.
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391. IKE
ECMWF @ 24 hours...

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390. IKE
This is as close to west as they have found....

From 238° at 16 knots
(From the WSW at ~ 18.4 mph)

Lowest pressure 1011.5 mb's.
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389. Vero1
TROPICAL WEATHER DISCUSSION...UPDATED
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT MON SEP 06 2010

...TROPICAL WAVES...

A TROPICAL WAVE JUST ENTERED THE FAR EASTERN ATLANTIC TROPICAL
BASIN...ANALYZED ALONG 15W S OF 16N MOVING WEST 10-15 KT.
SATELLITE DERIVED WINDS INDICATE BROAD CYCLONIC TURNING AROUND
THE WAVE AXIS. THIS WAVE IS EMBEDDED IN A SURGE OF DEEP LEVEL
MOISTURE AS NOTED ON TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED
MODERATE TO STRONG CONVECTION IS BETWEEN THE COAST OF WEST
AFRICA AND 23W FROM 8N TO 18N.

...ITCZ...

A MONSOONAL TROUGH EXTENDS FROM THE COASTAL WATERS OF W AFRICA
NEAR 8N17W CONTINUING WESTWARD ALONG 5N30W TO 8N40W...WHERE THE
ITCZ AXIS BEGINS AND CONTINUES WESTWARD ALONG 9N50W TO 8N60W.
SCATTERED MODERATE TO STRONG CONVECTION IS BETWEEN THE COAST OF
WEST AFRICA AND 23W FROM 8N TO 18N. THIS AREA OF CONVECTION IS
ALSO ASSOCIATED WITH A TROPICAL WAVE ALONG 15W S OF 16N. SIMILAR
CONVECTION IS WITHIN 100 NM ON EITHER SIDE OF THE MONSOONAL
TROUGH. SCATTERED WEAK TO ISOLATED MODERATE CONVECTION IS WITHIN
100 NM EITHER SIDE OF THE ITCZ.

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17:49:30Z 17.267N 57.150W 961.7 mb
(~ 28.40 inHg) 443 meters
(~ 1,453 feet) 1011.7 mb
(~ 29.88 inHg) - From 238° at 16 knots
(From the WSW at ~ 18.4 mph) 18.7°C
(~ 65.7°F) 13.4°C
(~ 56.1°F) 19 knots
(~ 21.8 mph) 56 knots*
(~ 64.4 mph*) 21 mm/hr*
(~ 0.83 in/hr*) 47.2 knots* (~ 54.2 mph*)
Tropical Storm*
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Quoting TheDawnAwakening:
ex Gaston does look to be on its way to becoming a tropical storm again. Convection developing is deep and the circulation is getting tighter. However I would still give him another 24 hours before any significant development would occur when he is in a more moist environment and wind shear is minimal. Also hopefully he spares Hispaniola and Puerto Rico any more rain problems, and moves to the south of these islands so he doesn't get shreded.

Gaston will do the same as Jeanne did in 2004
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Hermine seems to have bended more NW.
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Quoting itrackstorms:
I will probably take some bashing for this, but here goes...

Isn't it a waste to send RECON up to visit Hermine at this point? It's going to have excellent radar coverage and is essentially a nowcast event at this point. With the issues with the first flight, it will probably be another hour before the plane even gets to him and he may make landfall before they're even done (ok, maybe a little later then that).

I'm all for research and all of that, but this one seems like an opportunity to save some taxpayer money.

Oh wait... we're talking about the government.

Silly me.


Nothing wrong with voicing your opinion. Only thing is, Hermine is pronounced her-meen and is a female name.
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ex Gaston does look to be on its way to becoming a tropical storm again. Convection developing is deep and the circulation is getting tighter. However I would still give him another 24 hours before any significant development would occur when he is in a more moist environment and wind shear is minimal. Also hopefully he spares Hispaniola and Puerto Rico any more rain problems, and moves to the south of these islands so he doesn't get shreded.
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Quoting moonlightcowboy:
StormW, in this WV shot, is this energy spent off to the nwest by Gaston? I can't see what's causing that - no ull, no upper trough located there. Unless it's the swesterly flow that has managed to seperate some of the energy from the system in some layer of the ridge?

Appreciate your thoughts on this. TIA.



Gaston has a surface trough extending from him to the northwest and there is speed-convergence there due to a burst of easterly wind on his northern side that becomes slower downstream. This causes the air to pile up which forces it to rise, causing the thunderstorms you see to the northwest of Gaston.
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381. Skyepony (Mod)
Quoting StormJunkie:


Afternoon Skye. So you are thinking She could head a little further N? That radar just seems to show more westerly component than I would have expected.


If it made it past the tip of STX by really bombing hard the next few hours it might could make a decent jump north. She's just getting completely cut off from the tail she was born from, so no more east tugs. Don't know if she's got that much bomb to her.. unless that dropsonde was for real. Slight outside chance.
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Quoting Hurricanes101:


they are on the northern side of the system, that is why there are no west winds yet


Hence why I stated "no west winds reported JUST YET."
Member Since: April 14, 2007 Posts: 8 Comments: 5169
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Quoting ElConando:


Yep.


Thanks.

Quoting Cotillion:


Correct, the NHC issues watches/warnings for Puerto Rico directly.


Thanks.
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Quoting stormpetrol:
Ex Gaston looks to be finally organizing that it might get TD/TS Status by tomorrow morning, but is has stay just south of PR,Hispanola to survive!, jmo.


True. If it does make land-contact, it will most likely be ripped apart, considering the mountains and terrain.
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Quoting StormsAreCool:
Not many comments today. Where is everyone? You'd think it was a holiday or something.


I'm sure Labor Day has something to do with it. Everyone has amazing weather today--they're all outside enjoying it.
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Quoting StormW:


Not according to the steering layers forecast maps for the past week, where the flow has been predominately east to west. You do look at those, right?
Quoting StormW:


Not according to the steering layers forecast maps for the past week, where the flow has been predominately east to west. You do look at those, right?
yes i do and know how to do it and understand them VERY well. thank you.. the set-up 3 days or so was a classic recurve scenerio look at the 500-300 levels even now if he was strong with the upper low to his W he would be moving more wnw to nw since he didn't he is in the 700-850 level. remember physics and fluid dynamics, all hurricanes are just leaves in a river of flow
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Quoting HurricaneGeek:


That was easy. Thanks. I am blind jajaja

But for Puerto Rico, the NHC has the control of that because its a US territory. I would think so. ?


Correct, the NHC issues watches/warnings for Puerto Rico directly.
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Yes but mother nature also contradicted herself, but getting Earl to category four strength, but then weakened him to a tropical storm in roughly 24 hours, do to the EWRC, dry air and wind shear.
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Ex Gaston looks to be finally organizing that it might get TD/TS Status by tomorrow morning, but is has stay just south of PR,Hispanola to survive!, jmo.
Member Since: April 29, 2007 Posts: 0 Comments: 8134
Earl could have made landfall in NC if it didn't do that erratic jog to the east. Follow that track 50 miles west of the actual track, it would have been a bigger problem for the East Coast. The east jog did it!
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Quoting HurricaneGeek:


That was easy. Thanks. I am blind jajaja

But for Puerto Rico, the NHC has the control of that because its a US territory. I would think so. ?


Yep.
Member Since: September 6, 2009 Posts: 2 Comments: 3784
Recon. just got into ex-Gaston, and they should not be finding west winds north of the system. Let's see what they find after a few more hours.
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Thanks.
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Quoting StormsAreCool:
Not many comments today. Where is everyone? You'd think it was a holiday or something.


Considering it is a holiday, families are out to events, BBQ's, etc... and I don't think the blog is slow.. It's about average..
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StormW, in this WV shot, is this energy spent off to the nwest by Gaston? I can't see what's causing that - no ull, no upper trough located there. Unless it's the swesterly flow that has managed to seperate some of the energy from the system in some layer of the ridge?

Appreciate your thoughts on this. TIA.

Member Since: July 9, 2006 Posts: 184 Comments: 29610
Given the latest trends with radar showing an eyewall developing and visible satellite imagery showing deepening convection over and around the circulation center, it wouldn't be surprising to see Tropical Storm Hermine reach hurricane status tonight before making landfall.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
Quoting Cotillion:


THE GOVERNMENT OF MEXICO HAS ISSUED A TROPICAL STORM WARNING FOR THE
COAST OF MEXICO FROM TAMPICO TO THE MOUTH OF THE RIO GRANDE.

There you go, answered.


That was easy. Thanks. I am blind jajaja

But for Puerto Rico, the NHC has the control of that because its a US territory. I would think so. ?
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Not many comments today. Where is everyone? You'd think it was a holiday or something.
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I will probably take some bashing for this, but here goes...

Isn't it a waste to send RECON up to visit Hermine at this point? It's going to have excellent radar coverage and is essentially a nowcast event at this point. With the issues with the first flight, it will probably be another hour before the plane even gets to him and he may make landfall before they're even done (ok, maybe a little later then that).

I'm all for research and all of that, but this one seems like an opportunity to save some taxpayer money.

Oh wait... we're talking about the government.

Silly me.
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Hermine is going to cause more damage and trouble than Earl did. Kind of ironic considering Earl was nearly a Cat 5 projected to wreak a bit of havoc along the outer banks, eastern seaboard, Cape Cod, etc. and yet here we have Hermine which developed so rapidly, will only reach Cat1 status although given the rapid strengthening and improved characteristics on satellite a borderline Cat2 wouldn't even surprise me.

Another lesson that Mother Nature will do what she wants, when she wants, and not even the best computer models/ensembles can pick up on everything.
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Quoting cchsweatherman:


Not finding anything significant. Did record one tropical storm force wind reading, but everything else has been at tropical depression strength. Also, pressures are pretty normal at around 1011 mb thus far and no west winds reported just yet.


they are on the northern side of the system, that is why there are no west winds yet
Member Since: March 10, 2010 Posts: 1 Comments: 7874
Quoting HurricaneGeek:
For countries that are not the US, for example Mexico and Hermine how are warnings and watches posted?
Does the Mexican government request them or does the NHC recommend the Mexican government to issue them? What happens? Thanks.


Yes the Mexican Government is the one that does so and relays the info to the NHC who will put it on their advisories to inform Citizenry of Mexico or any other country.
Member Since: September 6, 2009 Posts: 2 Comments: 3784
Quoting Skyepony:
Fun~ AF303 is flying Gaston at ~1000'. Must not be expecting much.


Not finding anything significant. Did record one tropical storm force wind reading, but everything else has been at tropical depression strength. Also, pressures are pretty normal at around 1011 mb thus far and no west winds reported just yet.
Member Since: April 14, 2007 Posts: 8 Comments: 5169
Quoting HurricaneGeek:
For countries that are not the US, for example Mexico and Hermine how are warnings and watches posted?
Does the Mexican government request them or does the NHC recommend the Mexican government to issue them? What happens? Thanks.


Pretty sure the local weather services in the countries have government officials posted on what is happening. Im sure they give them a heads up on when warnings should be posted. Although I dont doubt at all that all these agencies communicate with each other, including the NHC.
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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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