Ana and TD 3 take aim at the Lesser Antilles

By: Dr. Jeff Masters , 4:17 PM GMT on August 15, 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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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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Quoting serialteg:


That's bad. Sadly, some people don't have the means to construct or move into solid, anti-hurricane settlements. Then again, there's something that my mother told me once when people kept rebuilding in tornado alley: "Why don't they just move?"

Well, I know moving ain't easy, and life sure gets complicated. But if I were these people, I would be sure to erect whatever I was to erect in a very hurricane - proof way from then on.



There are no Cat 5 building codes. If there were, buildings constructed to them would not be affordable to most people.
Member Since: September 23, 2005 Posts: 15 Comments: 11343
Quoting IKE:


It's thundering here now in the panhandle.

More rain.


pretty darn muggy and warm out too.. just hoping this blob doesn't form anything for you guys up north or in the gulf..
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Many people I know road out Opal in grid lock traffic on Hwy 29.
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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.
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557. jipmg
Quoting ackee:
I think each of us need to be our own computer models what we are seeing happening to TD#3 what the models are saying are diffrent my view


I agree..
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Quoting LPStormspotter:


Yes.wrong look up hurricane alicia
...or Camille or Audrey
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Keys Invest:

Station SMKF1

Wind Direction (WDIR): W ( 260 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): 30.05 in
5-day plot - Pressure Tendency Pressure Tendency (PTDY): 0.02 in ( Rising )
5-day plot - Air Temperature Air Temperature (ATMP): 73.6 F
5-day plot - Dew Point Dew Point (DEWP): 70.3 F
5-day plot - Tide (above MLLW) Tide (above MLLW) (TIDE):
Member Since: Posts: Comments:
554. 996tt
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?
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Quoting IKE:


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

it appears to begoing forward at 285 degrees wnw
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552. IKE
Quoting indianrivguy:
449. nrtiwlnvragn 1:58 PM EDT on August 15, 2009

492. sporteguy03 2:05 PM EDT on August 15, 2009

and Ike.. thanks for the help, I appreciate it!


You're welcome.


Rains moving in now.....again.....

Member Since: June 9, 2005 Posts: 23 Comments: 37860
Does anybody have more information about the new African wave?


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DATE/TIME LAT LON CLASSIFICATION STORM
15/1745 UTC 11.3N 34.4W T2.5/2.5 03L -- Atlantic
15/1745 UTC 14.4N 49.2W T1.5/2.5 ANA -- Atlantic
Member Since: August 23, 2008 Posts: 7 Comments: 5300
Quoting JupiterFL:


I went down to help clean up after Andrew. It looked like someone dropped an atomic bomb on Naranja, Cutler Bay and Homestead. I told myself then that I would never see anything like that again in my life.


That's bad. Sadly, some people don't have the means to construct or move into solid, anti-hurricane settlements. Then again, there's something that my mother told me once when people kept rebuilding in tornado alley: "Why don't they just move?"

Well, I know moving ain't easy, and life sure gets complicated. But if I were these people, I would be sure to erect whatever I was to erect in a very hurricane - proof way from then on.

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548. jpsb
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?
You are mostly right, however there have been GoM hurricanes that though small in size grew very powerful, I think Carla was one. If they meander slowly around in the Gulf they can grow into pwerful storms. Ususally not, but there are exceptions.
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547. ackee
I think each of us need to be our own computer models what we are seeing happening to TD#3 what the models are saying are diffrent my view
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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?


Yes.wrong look up hurricane alicia
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543. jipmg
doesn't seem to be a jog.. ANA is moving north of due west, and convection is wraping around its east side nearing the center
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449. nrtiwlnvragn 1:58 PM EDT on August 15, 2009

492. sporteguy03 2:05 PM EDT on August 15, 2009

and Ike.. thanks for the help, I appreciate it!
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528. pcolasky 6:13 PM GMT on August 15, 2009
Quoting IKE:


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




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)


yep...remember that...everyone freaked cause of Erin a month before...
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Through 96 hours on the 12z Euro, it appears to be in line with the more northerly tip of the model consensus. This will still likely be a recurve this run, but it's getting closer.
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NHC is thinking another tropical low could form in the EATL
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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?
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537. eddye
who wants to go tropics talk i want some people to join me in there
Member Since: August 12, 2008 Posts: 0 Comments: 1386
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?


Well that is debatable. It depends on how fast it moves across the GOM and what track it takes.
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535. IKE
Quoting jaevortex:
ugh it's raining something fierce over here, thunder lightening.. i'm in homestead, florida.


It's thundering here now in the panhandle.

More rain.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting fldude99:
Luckily the Gulf is generally cooler than it has been in recent years so hopefully that blob fizzles out as it leaves the warm waters around the keys



??????
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Quoting jipmg:


eh I dont think you should be worried, they are very far away
If one of the models is taking Ana straight through Cuba why would you think I don't have to worry ? Cuba is only 90 miles N of Grand Cayman. Quoting Drakoen:
NHC will shift the track further south on Ana. HWRF has it into Cuba and GFDL has it going into the Caribbean.
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Ana soon begin to appear more organized and Bill looks amazingly like a hurricane, (obviously is not).. Here in Puerto Rico the panic button will tighten when at 5pm news.. the people know what is expected next week ...
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Member Since: September 23, 2005 Posts: 15 Comments: 11343
GOM 60 Hour Surface Current Forecas
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Pressure still high at the stations

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Quoting IKE:


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



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)
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Quoting WhereIsTheStorm:


I completely agree. Been through a couple of Hurricanes now and don't want to see another. I was north of Fort Lauderdale when Andrew hit; but got to see the damage upfront and personal the day after. One storm knocked out power for 15 days. Nope, don't want anything coming in this direction. And don't wish this on anyone.


I've been wanting to write this here now for a while but haven't, mainly because some people really hate hurricanes - and they have all the right in the world to do so.

15 days of no power is equal to something very extraordinary happening. Hurricanes do have this tendency to bring people together like few things can, on a regular basis, and dare I say so, not on a terribly catastrophic level depending on where you live and what the conditions are. I've been thru Hugo, Georges, and countless other hurricanes, tropical storms, depressions (personal and tropical) and always marvel at those times where life totally changes, if for a moment, maybe a couple of days, a week, and you reconnect with neighbors. Maybe even meet people you lived alongside and didn't even know. Helped with any debris on the road, with a neighbor's house, or even with a total stranger, maybe even putting your life on the line.

Adrenalin junkie? Maybe. I love these systems - there's no doubt about that. I respect them, though, and live in solid cement houses, in places where the ground is not shifting underneath me, and currents aren't gonna carry me away. In other words, 15 days of no power? Bring it on!
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526. jipmg
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?


its a small low, it can explode quickly, CMC was poiting to that earlier today, but it can also fall apart quickly.
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ugh it's raining something fierce over here, thunder lightening.. i'm in homestead, florida.
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12z Euro is faster and farther south than the 0z Euro through 84.
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12z HWRF is total BS with ana as it takes through cubas large mountians which can really disrupt any tc as you saw what happened with ernesto.It actually barely weakens the storm over land. Expect a southerly shift to the NHC track through the florida straits later this afternoon.
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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..
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Convection is interesting. GOM wave is certainly worth mentioning and keeping a very close eye on. Convection is best in this area then across the Atlantic Ocean basin.
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In my humble opinion, even if the GOM blob did develop, it couldn't get that strong before hitting somewhere. Am I wrong?
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Luckily the Gulf is generally cooler than it has been in recent years so hopefully that blob fizzles out as it leaves the warm waters around the keys
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The GOM is a BAd seed,I dont like it,no siree

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516. jipmg
Quoting Nolehead:
485. sammywammybamy 6:04 PM GMT on August 15, 2009
Quoting tropicaltank:
Get ready for explosive development in the gulf.



WISHCASTER LISTEN TO THE NHC

PRESSURES REMAIN HIGH IN THIS AREA...
AND ANY ADDITIONAL DEVELOPMENT...IF ANY...SHOULD BE SLOW TO OCCUR
AS THE SYSTEM MOVES NORTHWESTWARD OVER THE EASTERN GULF OF MEXICO.



um no wishcaster here..look for yourself is all i can say...the NHC isn't always perfect...


True, you cant call someone a wishcaster, he is just saying what appears to be occuring.
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515. ackee
TD#3looks bad think will move more west than models are saying now my view
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Quoting Drakoen:


MY Melodramatics? Please. Don't flatter yourself.
Though a 6 year lurker, I am new to posting. I noticed that Weather Student's posts have been shaded out. has he been banned?
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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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