Ana and TD 3 take aim at the Lesser Antilles

By: Dr. Jeff Masters , 16:17:GMT den 15. august 2009

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Tropical Storm Ana was born this morning, when the remnants of Tropical Depression Two made a comeback and organized into the first tropical storm of the 2009 Atlantic hurricane season. Ana is the latest first named storm of the season since Hurricane Andrew got its name on August 17, 1992. The two storms have some similarities, as Andrew formed in the same part of the ocean, and also struggled in its early days with high wind shear and dry air. Let's hope the similarities end there.

Ana is struggling this afternoon. After an modest burst of heavy thunderstorm activity prompted NHC to upgrade Ana to a tropical storm early this morning, Ana has run into strong upper-level winds from the west that are creating high wind shear. This shear was not forecast, and it is not clear how long it will last. The shear has acted to drive dry air into the core of Ana, destroying almost all of Ana's heavy thunderstorms. The low-level center of the storm is now exposed to view, something that often foreshadows the death of a storm. It is possible the shear will destroy Ana, and several models (the GFS and ECMWF) forecast this may be the case. However, the shear forecast calls for shear to drop into the low range, 5 - 10 knots, tonight through Tuesday. If the shear does drop as forecast, Ana should be able to moisten the atmosphere around it sufficiently to protest itself from the dry Saharan air that surrounds it (Figure 1). SSTs are 27°C today, and will increase to 28°C by Sunday. By the time Ana moves into the Bahamas, total ocean heat content rises steeply (Figure 2), and rapid intensification of Ana is possible, if the shear and dry air haven't disrupted the storm. The intensity forecast models, for the most part, predict a steady intensification of Ana to the threshold of hurricane strength five days from now. The HWRF model is on the strong side, predicting a Category 2 hurricane. The GFDL predicts a weak tropical storm five days from now, but that is because the model has Ana passing over the rugged terrain of Hispaniola, something the other models do not predict. In summary, the intensity forecast for Ana has higher than usual uncertainty, and I give equal chances that the storm will be a hurricane--or non-existent--four days from now.


Figure 1. Water vapor image from this morning showing the large area of dry, Saharan air surrounding Ana, and lying to the north of Tropical Depression Three. Image credit: NOAA/SSD

Tropical Depression Three forms, could be Bill later today
QuikSCAT data from this morning and satellite loops revealed that the tropical wave (90L) in the middle Atlantic has finally developed a well developed surface circulation and can be classified as Tropical Depression Three. Recent satellite imagery suggests that TD 3 may already be Tropical Storm Bill. Water vapor imagery (Figure 1) shows that TD 3's center consolidated a few hundred miles south of the dry air of the Saharan Air Layer (SAL). Thus, the storm should not be affected by dry air and dust as much as Ana has been. Ana may also act to moisten the atmosphere in front of TD 3, helping protect the storm from the SAL as it edges farther north over the the three days.



Figure 2. Heat content of the ocean, in kJ per square cm. Oceanic heat content steadily increases for Ana and TD 3 as they approach the Lesser Antilles Islands. Oceanic heat content levels of 90 kJ per square cm are frequently associated with rapid intensification of hurricanes. Image credit: University of Miami.

Wind shear is moderate, 15 knots, but is forecast to fall to 10 - 15 knots on days 2 - 5. Sea Surface Temperatures are about 27.5°C, and will remain in the 27.5 - 28°C range the next five days. The combination of low wind shear and sufficiently warm SSTs should allow TD 3 to intensify steadily, and I expect the storm will be at hurricane strength by Wednesday, when it will be near the northern Lesser Antilles Islands. Most of our reliable intensity models strengthen TD 3 into a hurricane by Wednesday. Oceanic heat content (Figure 2) increases sharply just before the islands, so TD 3 could be intensifying rapidly as it moves through or just north of the Lesser Antilles on Thursday. TD 3 consolidated farther south than expected, so the track models calling for a more northerly path were probably incorrect. In particular, the ECMWF model, which had TD 3 turning sharply northwestward and missing the Lesser Antilles Islands, was probably much too far to the north in this morning's 00Z run. TD 3 will probably pass very close to the northern Lesser Antilles islands on Wednesday and Thursday.

I'll have an update Sunday.

Jeff Masters

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Is that correct that we have another low invest at 35 & 10? that is REALLY close to TD3 or is that TD3 and they are just duplicating? I found this on the front page of WU. Please let me know. Thanks!
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Quoting Drakoen:



All of that is possible. Still too early to tell the model really have been flip flopping on this trough.
Agreed. I think once it gets its act together they will get a handle on it. Until Then it Work, Soccer Practice for my Daughter big tournament coming up in Labor Day in Sarasota. And of course Work some more. LOL
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Link

The thunderstorms of the ne side of Ana are blowing up looks like its trying to get over the center. Also looks like Ana may be moving a little north of west.
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611. Skyepony (Mod)
On ANA Best models by far start with OCF last few runs aiming for a Frances/Jeanne area landfall on FL, NOGAPS, Clip & CLP5 distant chasers but doing well, GFDL, mm5 LGEM & HWRF follow, farther back BAM, LBAR. While CMC is at the back of the pack.
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610. jipmg
Quoting WPBHurricane05:


Link


looks like the models are taking it right over the islands, or just to the north
Just multi-tasking - Tiger and the FL blob. Took in a streaming webcam of what's happening around Islamorada - take a look:

http://www.chesapeake-resort.com/webcam.html
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Quoting Drakoen:
All I am saying is we don't need a hit. I'm not going in depth about the electricity situation and then 100 questions i'm getting asked. Simply put I like things the way they are.


who "needs" a hit? :/

sorry, i didn't know you didn't like to be asked questions... people sure seem to do that to you here
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Quoting jipmg:


oh can I have a link to them, I somehow keep closing that window -_-


Link
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Back in 2007, I went to bed with a TD in the Gulf, and when I woke up, I had a hurricane. (Humberto). I also am old enough to remember Camille. Back in those old chalkboard days, forecasting was much tougher. I can remember the weatherman drawing a cone from Houston to Tampa. That's how unsure they were. And even today GOM 'canes can be the most unpredictable of the lot
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605. IKE
Quoting AllyBama:
Ike,

are you hogging all the rain today? I haven't had a drop at my house yet and don't want any!..lol


Fixing to get it, within 10-15 minutes.
Member Since: juni 9, 2005 Posts: 23 Comments: 37860
Quoting AllyBama:
Drak, get you a generator and then a small window AC unit - at least you can use it to cool sleeping area.


After Katrina,and for 19 days,13 of them with no juice,and without a doubt,with all we were busy with,..having 5 gals a fuel a night a gen and a window A/c like we did was the only slice of comfort we had.

A good 600 bucks and one can have that as a Priority must have item on yer prep list.
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Quoting serialteg:


I know you love me, man. Let it out. A little love won't hurt


I don't even know you. Anybody that considers anyone in this blog above their family members needs help.
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602. jipmg
Quoting WPBHurricane05:


Yes. GFDL, HWRF, and the 3 BAM models show that.


oh can I have a link to them, I somehow keep closing that window -_-
All I am saying is we don't need a hit. I'm not going in depth about the electricity situation and then 100 questions i'm getting asked. Simply put I like things the way they are.
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Ike,

are you hogging all the rain today? I haven't had a drop at my house yet and don't want any!..lol
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Well, I guess we don't have to worry about TD3 anymore - looks like it will be going out to sea.....

Link
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Quoting WeatherStudent:
Exactly, but what can we do when so many folks on here this afternoon are wishcasting that insignificant puny blob currently moving through Key West. :)


Take a break, relax and realize the 12z models of today might not be the same as the 12z models of tomorrow.
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Quoting jipmg:


do the models show it moving WNW in the short term? Seems to be doing that right now


Yes. GFDL, HWRF, and the 3 BAM models show that.
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Quoting WeatherStudent:
Exactly, but what can we do when so many folks on here this afternoon are wishcasting that insignificant puny blob currently moving through Key West. :)


I don't see anyone wish casting that blob. I do however see you getting ignored though :) -poof goes ws-
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Quoting Drakoen:


Ride it out with your family. We are just people behind computers that post everyday.


I know you love me, man. Let it out. A little love won't hurt
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554. 996tt 6:18 PM GMT on August 15, 2009
Quoting Nolehead:
510. IKE 6:10 PM GMT on August 15, 2009
Quoting Bailey1777:
Any chance the blob in the GOM gets far enough West to give us some precip in Houston?


NHC says it's moving NW. That would put it coming in around Mobile/Pensacola.

lol..great let me get my red carpet out..



Welcome to the jungle. How long til the swell gets here?


hope this late afternoon or early dawn patrol!!!

Pcolasky...yeah i was working downtown p'cola took me 2 hours using every back road i knew to get me to my house on 9 mile...crazy!!!
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Quoting Drakoen:


I don't want to have to deal with the noise and the Carbon emission.


wait. so you like power, don't wanna lose it, but don't want a generator either?
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Drak, get you a generator and then a small window AC unit - at least you can use it to cool sleeping area.
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Quoting serialteg:


I'm actually always thinking about my Internet connection and riding it out with you guys on...

*aww* :D


Ride it out with your family. We are just people behind computers that post everyday.
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Quoting WeatherStudent:
Exactly, but what can we do when so many folks on here this afternoon are wishcasting that insignificant puny blob currently moving through Key West. :)

And makes Ana look like a fart.
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Station MLRF1 (FL Keys)

Wind Direction (WDIR): SSW ( 200 deg true )
5-day plot - Wind Speed Wind Speed (WSPD): 23 kts
5-day plot - Wind Gust Wind Gust (GST): 26 kts
5-day plot - Atmospheric Pressure Atmospheric Pressure (PRES): 29.99 in
5-day plot - Pressure Tendency Pressure Tendency (PTDY): -0.04 in ( Falling )
5-day plot - Air Temperature Air Temperature (ATMP): 77.5 °F
5-day plot - Water Temperature Water Temperature (WTMP): 86.2 °F
5-day plot - Salinity Salinity (SAL): 36.04 psu

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586. jipmg
Quoting WPBHurricane05:
Another southerly shift with Ana at 5pm. Its looking more and more likely that she will take the death trip (Hispaniola and Cuba). Bad news for both Ana and Hispaniola/Cuba.


do the models show it moving WNW in the short term? Seems to be doing that right now
Quoting WeatherStudent:
Exactly, but what can we do when so many folks on here this afternoon are wishcasting that insignificant puny blob currently moving through Key West. :)

Its the closest thing to home.
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Quoting Drakoen:
All I know is I can't sleep without my air conditioner on. Fans do not suffice. We don't need a storm. I like my house and my electricity.


I'm actually always thinking about my Internet connection and riding it out with you guys on...

*aww* :D
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583. jipmg
Quoting WeatherStudent:
Exactly, but what can we do when so many folks on here this afternoon are wishcasting that insignificant puny blob currently moving through Key West. :)


listen, it doesn't matter what you say, if something is forming its forming, if something is dissiapting its dissipating, if people wishcast that doesnt mean all of a sudden the storms are going to form. If people down cast its the same thing.

Say what your eyes are seeing, and what reports are saying, dont say something is going to die or strengthen just because you want it to.
esto merece un aplauso! it is true what you say, I do not know if to the people in the states the same thing happen, but here in Puerto Rico hurricanes are some of the events that unites the people...bravo por eso!
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Another southerly shift with Ana at 5pm. Its looking more and more likely that she will take the death trip (Hispaniola and Cuba). Bad news for both Ana and Hispaniola/Cuba.
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Quoting ClearwaterSteve:
Hey Drak, Just looked at the latest GFS, Looks like the blob by the keys skirts the coast of Fl (West) basically a rainmaker, Ana Disolves through the Islands and TD3 finds a hole in the ridge and bends up.

Thoughts



All of that is possible. Still too early to tell the model really have been flip flopping on this trough.
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Quoting BiloxiGirl:
In my humble opinion, even if the GOM blob did develop, it couldn't get that strong before hitting somewhere. Am I wrong?


Many times the storms that are born in the GOM are not good-take Opal for example back in 95. Started in Bay of Campeche and made a beeline for Pensacola
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Quoting Funkadelic:


I know right! It is so annoying, hearing a bunch of garbage all day long when we have ACTUAL systems out there to track. I gues people in the GOM want to be hit? I dont understand their mental state to be honest.

The NHC may not ALWAYS be correct,but they arent stupid and if they were concerned about something this close to land, then you would hear about it.



They weren't concerned about Humberto, either.
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Quoting BiloxiGirl:
In my humble opinion, even if the GOM blob did develop, it couldn't get that strong before hitting somewhere. Am I wrong?


I thought there was a front in the SO CONUS pushing south that might stall a storm in the GOM for a while without forward direction.
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Quoting Vortex95:


No generator eh? had 1 week no electricity after andrew and 3 days for wilma. We got a Generator in 2006. We havn't had to use it... yet.


I don't want to have to deal with the noise and the Carbon emission.
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Quoting IKE:


I was just going by what the NHC said. You may be right.

That blob needs to be 91L.
it will be 92l ike the navy used 91l last night on ana before she went to ts
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Want to be hit? The past 4 years I've endured Rita, Humberto, and Ike. I doubt many of us are making that claim.
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Hey Drak, Just looked at the latest GFS, Looks like the blob by the keys skirts the coast of Fl (West) basically a rainmaker, Ana Disolves through the Islands and TD3 finds a hole in the ridge and bends up.

Thoughts
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Quoting Funkadelic:


I know right! It is so annoying, hearing a bunch of garbage all day long when we have ACTUAL systems out there to track. I gues people in the GOM want to be hit? I dont understand their mental state to be honest.

The NHC may not ALWAYS be correct,but they arent stupid and if they were concerned about something this close to land, then you would hear about it.


I agree. Nothing to worry about now. Surface pressure are high. None of the computer models show development.
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Quoting nrtiwlnvragn:


There are no Cat 5 building codes. If there were, buildings constructed to them would not be affordable to most people.


Yes, true...

But Category 5 hits are the maximum end of the scale, not the ONLY scale. You prepare yourself as best you can, even on the humblest of budgets, but intelligence.
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Same bouy updated:

Wind Direction (WDIR): SW ( 230 deg true )
5-day plot - Wind Speed Wind Speed (WSPD): 19 kts
5-day plot - Wind Gust Wind Gust (GST): 21 kts
5-day plot - Atmospheric Pressure Atmospheric Pressure (PRES): 30.04 in
5-day plot - Pressure Tendency Pressure Tendency (PTDY): -0.02 in ( Falling )
5-day plot - Air Temperature Air Temperature (ATMP): 75.4 °F
5-day plot - Dew Point Dew Point (DEWP): 69.1 °F
5-day plot - Tide (above MLLW) Tide (above MLLW) (TIDE): 0.85 ft
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Quoting Catfish57:
PaTrap...

I mentoned in an earlier post that a TD or weak TS might be what the doctor ordered to take the edge off some of these incredible GOM SST's. Your thoughts?


As K and Rita and Wilma All Showed in 2005,TCHP and upwelling dont alway's bring the Mixing one desires to see. This year were even warmer as 05.
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565. IKE
Quoting KEEPEROFTHEGATE:
it appears to begoing forward at 285 degrees wnw


I was just going by what the NHC said. You may be right.

That blob needs to be 91L.
Member Since: juni 9, 2005 Posts: 23 Comments: 37860
Quoting pcolasky:


Sure hope the blob doesn't have any surprises. I can remember going to bed with a weak Cat 1 and waking up to a strong Cat 2 (Opal in 1995)


now THAT brings back memories
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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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