Intensifying Hermine closes in on the Texas/Mexico coast
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
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06Sep . 12pmGMT - - 22.4n95.3w - - 45mph - - - 995mb - - NHC.Adv.#2A
06Sep . 03pmGMT - - 23.4n95.8w - - 50mph - - - 998mb - - #3
06Sep . 06pmGMT - - 24.1n96.5w - - 60mph - - - 995mb - - #3A
06Sep . 09pmGMT - - 24.5n97.0w - - 60mph - - - 992mb - - #4
07Sep . 12amGMT - - 24.8n97.1w - - 65mph - - - 991mb - - #4A
1:30amGMT landfall on 25.3n97.4w @ 65mph & 991mb (not used on the plot chart)
07Sep . 03amGMT - - 25.5n97.5w - - 60mph - - - 991mb - - #5
07Sep . 06amGMT - - 26.1n97.7w - - 60mph - - - 991mb - - #5A
07Sep . 09amGMT - - 27.0n98.0w - - 50mph - - - 993mb - - #6
07Sep . 12pmGMT - - 27.7n98.2w - - 45mph - - - 995mb - - #6A
Copy and paste 22.4n95.3w, 23.4n95.8w, 24.1n96.5w, 24.5n97.0w, 24.8n97.1w-25.5n97.5w, 25.5n97.5w-26.1n97.7w, 26.1n97.7w-27.0n98.0w, 27.0n98.0w-27.7n98.2w, crp, mam, sat into the GreatCircleMapper for a look at the last 12hours.
As I posted just a short while ago: We've seen the birth of five named storms in just the last 14-days, we had a landfalling high-end tropical storm only nine hours ago, our ACE is well over half of long-term normal, and there's a very vigorous wave rolling off of Africa this morning with more behind it. Throw in what's left of Gaston, which still has a chance (albeit ever-so-slight)...so why are we back to the silly bustcasting?
Finally, two reminders: 1) the season is not halfway over climatologically-speaking...and this fall promises to be very much backloaded; 2) there's still much more to come from Africa, but even were the CV train to stop right this minute, that doesn't mean we'd be safe or that the season would be over. Remember that Katrina, Wilma, Mitch, the 1935 Labor Day Storm, and Camille--among many others--were homegrown.
It's September 7th, guys.
ok edit to ur edit lol
the CoC is not settled it will redefine/move IF gaston does redevelop in 48 hours
Lowest he's ever been.
Don't know whether it is closed or not but looks like the coc is just north of 16 and west of 62. IDK maybe he is still making a slight effort.
(1)Alex.
And also...it didn't hit the USA(lower 48), as a major impact. I'm talking Ike kind...or Katrina...or Hugo....or Camille....Ivan....Georges...Wilma.
Wow!
I was not aware of most of this. I haven't commented on the pace of the season, but this is certainly an eye opener.
Awesome job!
That is sadly true. I hear the locals here talk about how the NHC hypes seasons and how we haven't had any hit in years here. They seem to not count all those storms that hit other countries or go out to sea.
For weather conditions in Puerto Rico.
Link
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.
Surprised NHC has ex-Gaston at 10% but what do I know...
Incredible amount of rain getting dumped on TX this a.m.
That's quite a view Keeper (#1613).
I figure they believe he will regenerate eventually, just not in 48 hours so they are leaving him with a small percentage chance so they don't drop him to zero and have to jump him back up again.
Wish I didn't have to work today but had best get it in gear. Have a good one every1.
Good work, Neo. Yup, lots of season left yet.
Vorticity is hanging, barely with Gaston. He's in ZERO shear. If he's gonna make a move, not sure conditions will ever be any more conducive.
It's cool.
The last tropical cyclone of the season formed on October 5 from a westward moving tropical wave, south of Cuba. It strengthened to a 50 mph (80 km/h) tropical storm before crossing the island, and remained intact, becoming a hurricane over the Bahamas on the 7th. A cold front pulled Janice northward, and the hurricane became extratropical on the 12th, after causing between $200,000-$300,000 in damage (1958 dollars) in the Bahamas and one death. An early report indicated 18 Haitians died when their raft capsized in the Bahamas, though that was later proven false. Heavy flooding occurred in Jamaica and Haiti as well.
Link
M I M I C imagery
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.
Thanks Hermione, we needed the rain up here in Fort Worth! My sprinkler controller is now set to off!!!!
2nd day with no cigarettes...
afraid I'll get banned...
@ Dewey, Apple rocks.. DUDE (see)
back to lurking...
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