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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1686. wunderkidcayman
9:20 PM GMT on September 07, 2010
hey guys I just came back and what did I tell ya
Member Since: June 13, 2009 Posts: 2 Comments: 12716
1685. EtexJC
3:22 PM GMT on September 07, 2010
Quoting TropicalAnalystwx13:
Hermine is treating me with Heavy Rains here in Fort Worth this morning :)


That explains why i slept in until 10 this morning, lack of sun to wake me up, LOL (I'm in NRH)
Member Since: August 17, 2007 Posts: 0 Comments: 218
1684. JBirdFireMedic
2:05 PM GMT on September 07, 2010
NEW BLOG
Member Since: August 10, 2009 Posts: 0 Comments: 247
1683. Cotillion
1:49 PM GMT on September 07, 2010
Quoting Neapolitan:


ACE is simply the best metric yet devised for measuring the accumulated energy spent over he course of a season, and as such it is very effective at detailing overall activity. I suppose that, for some, body counts and dollar amounts are a more effective measure, but from a meteorological point of view, ACE works quite well. To put it another way, while the devastating impact of a short-lived and powerful storm like Camille means more to the general population--that is, normal folks, journalists, insurance adjusters, and the like--its relatively low ACE says nothing much about the overall power of a particular season.

(Yes, ACE-wise, 2007 was low-normal...but half its total ACE came from one storm--Dean. This year's short-lived Alex was more energetic than 12 of that year's 14 mostly weak systems. When making year-to-year comparisons on which a season's "bustedness" is based, ACE works.)


I do like ACE personally, so not disputing its worth. Its significance as an indicator of activity really does depend on what you define as activity. ACE, by its very nature, will often put more into the 'long trackers' than numbers. In terms of activity being what the CSU would call 'hurricane days', then yes, it is a fine determinant.

However, if activity is defined by the quantity of storms (which for most it is), it is far less clear cut. There are numerous examples of seasons which have fewer numbers in all three categories - Storm, Hurricane, Major - yet have higher ACE due to that season's propensity to/reliance on an active Cape Verde season.
Member Since: August 23, 2008 Posts: 7 Comments: 5300
1682. Eugeniopr
1:35 PM GMT on September 07, 2010

IKE:

Take a look

http://www.comoestaeso.com/forums/content.php?23-Live-Ocean-Park-Camera

Cloudly with 8KT winds, good for board padling

Member Since: August 1, 2010 Posts: 0 Comments: 258
1681. taco2me61
1:34 PM GMT on September 07, 2010
Good Morning Everyone,
Checking in from the Beautiful Island of Key West....
Had a wild Storm last night but was kinda cool looking over the water with the light show....

I see we had Hermine last night and explains why we had winds moving to the west....

well now we need to see what Ex-Gaston does and the new wave moving into the Atlantic....

Taco :o)
Member Since: July 7, 2005 Posts: 6 Comments: 3261
1679. Neapolitan
1:31 PM GMT on September 07, 2010
Quoting Cotillion:
ACE doesn't say that much about activity per se.

It measures intensity and time. If you wish to use the ACE comparisons as a means of determining activity, you run the risk of making seasons like 2007 a 'bust'. It wasn't.

It also says nothing for the human impact. In fact, it can even be the opposite. 1950 was a massive ACE year, taking into account that there was no satellite and radar was rare, it probably exceeded 2005 in ACE. Despite the intensity of those storms, only 20 lives were lost and the damage was dwarfed by previous and subsequent seasons.



ACE is simply the best metric yet devised for measuring the accumulated energy spent over he course of a season, and as such it is very effective at detailing overall activity. I suppose that, for some, body counts and dollar amounts are a more effective measure, but from a meteorological point of view, ACE works quite well. To put it another way, while the devastating impact of a short-lived and powerful storm like Camille means more to the general population--that is, normal folks, journalists, insurance adjusters, and the like--its relatively low ACE says nothing much about the overall power of a particular season.

(Yes, ACE-wise, 2007 was low-normal...but half its total ACE came from one storm--Dean. This year's short-lived Alex was more energetic than 12 of that year's 14 mostly weak systems. When making year-to-year comparisons on which a season's "bustedness" is based, ACE works.)
Member Since: November 8, 2009 Posts: 4 Comments: 13790
1678. futuremet
1:25 PM GMT on September 07, 2010
Quoting StormW:


That only happens with hurricanes...as a hurricane becomes more intense, the outflow above the system, being sinking air, warms, and basically creates or reinforces an upper level ridge.


That does not seem the case. If the conditions are right, all tropical cyclones can develop upper level anticyclones. Tropical Storm Hermine (and many others) developed its own upper level anticyclone. When a tropical cyclone has strong surface convergence with virtually no wind shear above it, it will positively create its own upper level ridge. Sometimes mere intense convection activity at the surface can generate an upper level anticyclone.

A tropical cyclone's upper level ridge can also be enhanced by diffluent flow aloft from the eastern side of an upper level low. The curving diffluent air increases winds at the periphery of the upper level high. If a tropical cyclone is under too much shear, the upper level high will be negligible or displaced from the center. Overall, upper level anticyclogenesis depend on the environment.

Member Since: July 19, 2008 Posts: 43 Comments: 4051
1677. BLee2333
1:23 PM GMT on September 07, 2010
LOL!! Me too! First long weekend since before the Holidays and the weather was looking pretty darn good for SE AL/NW FL! Enjoyed it! ;)
Member Since: January 6, 2009 Posts: 0 Comments: 217
1676. hulakai
1:23 PM GMT on September 07, 2010
Several models develope Ex-G into a hurricane. Climatologicly based on TDs in the area(if my coordinates are correct 63W and 17N)there is a 40% chance of a conus hit between Southern Texas and East Central Florida. The other 60% were fish. Based on current model tracks, folks in that area might want to pay attention.
Member Since: August 5, 2005 Posts: 0 Comments: 98
1675. MahFL
1:23 PM GMT on September 07, 2010
Looks like Hermine's eye is getting smaller on the radar.
Member Since: June 9, 2004 Posts: 0 Comments: 3829
1674. Orcasystems
1:23 PM GMT on September 07, 2010
Quoting clwstmchasr:
Gaston is still not dead.... its alive ...barely ...still ... again ...whatever.

Let go Orca! Let go...


ROFLMAO, I am willing to... its the darn models that keep it alive. One set says... nada... others say... TS... and three respected models including the SHIP say anywhere from a CAT 2- 4
Member Since: October 1, 2007 Posts: 81 Comments: 26516
1673. ho77yw00d
1:22 PM GMT on September 07, 2010
New blog!!!
Member Since: July 3, 2010 Posts: 0 Comments: 427
1670. StormPro
1:20 PM GMT on September 07, 2010
Quoting BLee2333:
I wouldn't say inattentiveness. I had it as an OAI. However, there was such a large area of convection and general low pressure that I misjudged it. I thought with the bulk being over mexico and the Pacific waters, that the pacific side would dominate and any developement would have been on that side of Mexico and not in the BOC...


Oh I was refering to my inattentiveness...I wrote her off Friday evening...of course I was looking forward to wonderful weather for the long weekend here in South Louisiana
Member Since: August 4, 2010 Posts: 0 Comments: 606
1669. IKE
1:20 PM GMT on September 07, 2010
Member Since: June 9, 2005 Posts: 23 Comments: 37860
1668. surfmom
1:20 PM GMT on September 07, 2010
Post 1613 - Keeper .... looks like plenty of more ingredients for the STEW Pot is being exported as I type
Member Since: July 18, 2007 Posts: 30 Comments: 26536
1667. BLee2333
1:19 PM GMT on September 07, 2010
There's a fine line between insticts and wishcasting!
Member Since: January 6, 2009 Posts: 0 Comments: 217
1665. BLee2333
1:18 PM GMT on September 07, 2010
I wouldn't say inattentiveness. I had it as an OAI. However, there was such a large area of convection and general low pressure that I misjudged it. I thought with the bulk being over mexico and the Pacific waters, that the pacific side would dominate and any developement would have been on that side of Mexico and not in the BOC...
Member Since: January 6, 2009 Posts: 0 Comments: 217
1664. MoltenIce
1:18 PM GMT on September 07, 2010
Quoting AustinTXWeather:
Hermine is holding up well over land. Was a little surprised to see that center. We're expected to get heavy rain/winds today & tomorrow Link
Yeah, that's some eye for a TS.
Member Since: August 11, 2010 Posts: 0 Comments: 784
1662. surfmom
1:16 PM GMT on September 07, 2010
Quoting StormPro:
Good morning all....hermine is definately a lesson learned in inattentativeness

sometimes "Instinct" counts for a lot
Member Since: July 18, 2007 Posts: 30 Comments: 26536
1661. AustinTXWeather
1:15 PM GMT on September 07, 2010
Hermine is holding up well over land. Was a little surprised to see that center. We're expected to get heavy rain/winds today & tomorrow Link
Member Since: September 13, 2008 Posts: 0 Comments: 241
1660. MoltenIce
1:13 PM GMT on September 07, 2010
Quoting jason2010xxxx:
I think the bigger blob will get an orange soon.
Member Since: August 11, 2010 Posts: 0 Comments: 784
1659. StormPro
1:12 PM GMT on September 07, 2010
Good morning all....hermine is definately a lesson learned in inattentativeness
Member Since: August 4, 2010 Posts: 0 Comments: 606
1657. MoltenIce
1:11 PM GMT on September 07, 2010
Quoting FLdewey:

OOOOooo I had no idea you were anti Mac... it's all now very clear. I'm an Apple developer, so that's a fight we should just pass on.

Have fun with *giggle* your PC *giggle*

Hello fellow Mac user. :P
Member Since: August 11, 2010 Posts: 0 Comments: 784
1656. smuldy
1:11 PM GMT on September 07, 2010
Quoting FLdewey:

OOOOooo I had no idea you were anti Mac... it's all now very clear. I'm an Apple developer, so that's a fight we should just pass on.

Have fun with *giggle* your PC *giggle*

lol agreed and more than fair; and I have no problem with the software; its great; the hardware, that is another story lol
Member Since: July 23, 2010 Posts: 0 Comments: 527
1655. BLee2333
1:10 PM GMT on September 07, 2010
I wasn't on here all weekend, so this is the first opportunity I've had to comment on Hermine.

With that being said, please pass the tobasco.

I really didn't expect anything to develope when I was looking in that area Friday. Live and learn!
Member Since: January 6, 2009 Posts: 0 Comments: 217
1654. Orcasystems
1:10 PM GMT on September 07, 2010
Gaston is still not dead.... its alive ...barely ...still ... again ...whatever.


AOI

AOI

AOI

AOI

AOI

TS BUSTED FORECAST ALIBI
Member Since: October 1, 2007 Posts: 81 Comments: 26516
1653. smuldy
1:10 PM GMT on September 07, 2010
Quoting StormW:


That only happens with hurricanes...as a hurricane becomes more intense, the outflow above the system, being sinking air, warms, and basically creates or reinforces an upper level ridge.
im sure you will get to it in your blog later, but I am curious on your take for the long term prospects of ex-gaston; do you think the energy has a realistic chance of becoming anything if it can stay south or north of cuba? and do you think land interaction has anything to do with its long term cyclogenesis chances at this point? I know it is in moderate sheer and surrounded by dry air, but what wins out? the moderate (10-20kts) shear forecast to its north after crossing DR or the warm SSTs moist air? assuming here given lower shear is has a better shot if it stays south of cuba, and assuming land interaction could indeed kill it
Member Since: July 23, 2010 Posts: 0 Comments: 527
1652. Thundercloud01221991
1:10 PM GMT on September 07, 2010
man I go away and come back and expect that Hermine would have degraded some but it still has a closed eyewall...
Member Since: August 1, 2006 Posts: 28 Comments: 3716
1647. GeoffreyWPB
1:03 PM GMT on September 07, 2010
Member Since: September 10, 2007 Posts: 0 Comments: 11537
1646. tkeith
1:02 PM GMT on September 07, 2010
cant comment on posts...

2nd day with no cigarettes...

afraid I'll get banned...

@ Dewey, Apple rocks.. DUDE (see)

back to lurking...
Member Since: November 1, 2004 Posts: 25 Comments: 8937
1645. smuldy
1:02 PM GMT on September 07, 2010
Quoting KanKunKid:


I feel your pain.
hey i will gladly suffer tedious work if it ends up being lit ablaze and i get fractions of a cent on a billion transactions siphoned into my account lol
Member Since: July 23, 2010 Posts: 0 Comments: 527
1644. TexasHoosier
12:59 PM GMT on September 07, 2010
If you want to see a really amazing image of a tropical storm that did not fall apart as ingressed over land, select the Corpus Christi NEXRAD radar which shows an intact eyewall even after being ashore for several hours.

Thanks Hermione, we needed the rain up here in Fort Worth! My sprinkler controller is now set to off!!!!
Member Since: December 3, 2002 Posts: 0 Comments: 115
1643. VictoriaXroads
12:59 PM GMT on September 07, 2010
4" of rain here so far in S. TX. Gusting up to 33 mph or so but I'm about 80 miles to the NE of the center of the storm.
Member Since: July 27, 2010 Posts: 0 Comments: 2
1641. stormwatcherCI
12:58 PM GMT on September 07, 2010
Quoting StormW:


What was TD11-E in the EPAC had a piece of energy break away, and being close enough to Central America and MX, the energy made it to the BOC, and began to interact with a surface trof of low pressure. Given that the setup of the atmosphere allowed for lowering of pressures, we then had an upper level anticyclone develop over the area...that combined with very warm SST's, anf forced feedback from the center being close to MX, developed Hermine.
Good morning StormW. It looks like XGaston is developing his own anticyclone. Please correct me if I am wrong.
Member Since: October 9, 2008 Posts: 0 Comments: 8436
1640. Cotillion
12:57 PM GMT on September 07, 2010
Quoting KanKunKid:


It's interesting you should mention that. FEMA collected data that showed the same thing and in their efforts to keep loss of life down to a bare minimum in natural disasters, they correlated the rise in deaths over the last few decades and drew the conclusion that the main factor in the rising number of deaths was attributed to people developing and moving to and living in areas prone to damage from hurricanes and the after effects such as flooding. So if you live in harms way....


Interesting.

It might be a bit of both, though. Hurricane awareness and 'technology' is much better than it ever was. You look at all of the storms in the Atlantic that have caused considerable death (I'm talking thousands here), most occurred decades, even centuries ago. Only Mitch has been recent. Fifi in the last 35 years. Most occurred way before, even Flora is near 50 years ago now.

However, that trade off of the 'big killer', might be that the smaller storms will take death more than they otherwise would due to that development and migration to hurricane-prone areas.

Just a thought.
Member Since: August 23, 2008 Posts: 7 Comments: 5300
1638. GeoffreyWPB
12:55 PM GMT on September 07, 2010
Member Since: September 10, 2007 Posts: 0 Comments: 11537
1637. wxman69
12:54 PM GMT on September 07, 2010
Plenty of season left to be sure, and as has been mentioned many times, it will likely be active into/through October. The one plus is in another week or so, the Cape Verde season will be winding down. It will become increasingly unlikely anything developing that far east will ever get close to the states. The westerlies are beginning to edge further south already and are becoming more active. This will make recurvature increasingly likely. Then, after the 20th, these waves will tend to develop further west, which is when we need to be more concerned.
Member Since: May 19, 2008 Posts: 0 Comments: 4
1636. TropicalAnalystwx13
12:53 PM GMT on September 07, 2010
Hermine is treating me with Heavy Rains here in Fort Worth this morning :)
Member Since: July 6, 2010 Posts: 113 Comments: 32802

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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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