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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4214. drj27
so anyone think it could get to hurricane strength
Member Since: Posts: Comments:
Quoting cjnew:
Im in PC looks like it's coming...and nobody even knows yet. lol

Yea, I wish i could see the look on their faces when they turn on the tv when getting their cup of coffee...WTH! a TD! *spills coffee*

I have so much to learn about this stuff...if anything on radar..my idea would be that its less organized..but i shalt agree with Ike that there is more red around the center..i probably think it has to look perfect to be a storm lol
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4211. IKE
Reds on radar starting to wrap around TD4....

Member Since: June 9, 2005 Posts: 23 Comments: 37860
Yeah that part of Florida is hill country I know since I used I-10 to go on a trip once From Ft.Lauderdale to Houston
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4209. cjnew
Im in PC looks like it's coming...and nobody even knows yet. lol
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4208. IKE
IT SHOULD BE NOTED THAT SOME ADDITIONAL
STRENGTHENING PRIOR TO LANDFALL BUT AFTER THE 12 HOUR 45 KT
FORECAST INTENSITY SHOWN BELOW IS LIKELY.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting jipmg:
is it just me or does TD 4 seem slower than before no radar

Possibly the last few frames, but not really enough to tell, plus the center is a little bit more tricky to spot..
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RAINFALL ACCUMULATIONS OF 3 TO 5 INCHES...WITH ISOLATED MAXIMUM
AMOUNTS OF 10 INCHES ACROSS PORTIONS OF NORTH FLORIDA NEAR THE PATH
OF THE CENTER.

COASTAL STORM SURGE FLOODING OF 3 TO 5 FEET ABOVE NORMAL TIDE
LEVELS CAN BE EXPECTED NEAR AND TO THE EAST OF WHERE THE CENTER
MAKES LANDFALL.


From the advisory for TD4.
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Ty, I'm in PCB and the nws is saying 3-5 feet
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4204. jipmg
is it just me or does TD 4 seem slower than before no radar
4203. IKE
Quoting weatherblog:


True, the rain can be bad in any tropical systems, but as far as the wind goes this is not much different than an afternoon thunderstorm.


I live on a lake....up a hill....winds are exacerbated here because of a slight up-slope from the lake....

I road out a TS here before....house sits up off the ground....I'm not BS-ing....my house was shaking.

It was not fun.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
4202. drj27
guess im going to sleep nothing to worry about here in okaloosa county
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4201. TxKeef
anyone have a link to estimated storm surge potential for TD4, My dad currently lives in Destin, FL.
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4200. jipmg
Quoting Cotillion:


I think it has even more of a chance to be picked up by it.

Slow Bill/Fast trough = + chance of recurve.
Fast Bill/slow trough = - chance of recurve.

I think anyway.


but if it moves too slow wouldn't the trough miss it? I remember there was a mode yesterday slowing bill down a bit "GFS" and the trough picks it up but then bill turns west after that, I know its changed but just a curiousity
NWS just flashed the TS warning for the first time. Haven't seen THAT in awhile
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000
WTNT44 KNHC 160858
TCDAT4
TROPICAL DEPRESSION FOUR DISCUSSION NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042009
500 AM EDT SUN AUG 16 2009

DATA FROM THE WFO TAMPA RADAR INDICATE THAT THE DISTURBANCE IN THE
EASTERN GULF OF MEXICO HAS BECOME SIGNIFICANTLY BETTER ORGANIZED
OVERNIGHT. A QUIKSCAT PASS NEAR 00Z SUGGESTED THAT THERE PROBABLY
WAS A CLOSED SURFACE CIRCULATION. GIVEN THIS...ADVISORIES ARE BEING
INITIATED ON A NEW TROPICAL DEPRESSION. ALTHOUGH THERE WAS A SHIP
REPORT FROM A CARNIVAL CRUISE LINE VESSEL OF 40 KT...THIS REPORT IS
NOT CONSIDERED TO BE REPRESENTATIVE OF THE SURFACE WINDS. DOPPLER
VELOCITIES FROM THE TAMPA RADAR ALSO DO NOT SUPPORT TROPICAL STORM
STRENGTH AT THIS TIME. HOWEVER...THE EXCELLENT RADAR PRESENTATION
AND DEEP CONVECTION SUGGESTS THAT STORM STATUS IS LIKELY TO BE
ATTAINED SOON. VERTICAL SHEAR IS VERY LOW...AND THE INTENSITY
GUIDANCE FROM THE HWRF AND GFDL SUGGEST A MIDDLE-RANGE TROPICAL
STORM BY LANDFALL. IT SHOULD BE NOTED THAT SOME ADDITIONAL
STRENGTHENING PRIOR TO LANDFALL BUT AFTER THE 12 HOUR 45 KT
FORECAST INTENSITY SHOWN BELOW IS LIKELY.

THE INITIAL MOTION IS 330/13. THE CYCLONE IS MOVING AROUND THE
PERIPHERY OF THE SUBTROPICAL RIDGE AND IS EXPECTED TO MAINTAIN THIS
APPROXIMATE TRACK UNTIL LANDFALL. THE OFFICIAL FORECAST IS CLOSE TO
A CONSENSUS OF A FAIRLY TIGHTLY CLUSTERED GUIDANCE SUITE.

THIS IS A VERY SMALL TROPICAL CYCLONE...AND ITS EFFECTS ARE LIKELY
TO REMAIN RATHER CLOSE TO THE PATH OF THE CENTER.


FORECAST POSITIONS AND MAX WINDS

INITIAL 16/0900Z 27.7N 83.9W 30 KT
12HR VT 16/1800Z 29.2N 85.0W 45 KT
24HR VT 17/0600Z 31.0N 86.7W 40 KT...INLAND
36HR VT 17/1800Z 33.0N 87.5W 20 KT...DISSIPATING INLAND
48HR VT 18/0600Z...DISSIPATED

$$
FORECASTER FRANKLIN
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Quoting jipmg:
what would a slower moving Bill mean in regards of the trough?


I think it has even more of a chance to be picked up by it.

Slow Bill/Fast trough = + chance of recurve.
Fast Bill/slow trough = - chance of recurve.

I think anyway.
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Im in PCB, yah.....LOL!!! I was up at about 12:30am taking the puppy out and noticed the wind had picked up. Figured when I woke up and read the AFD that it'd say the gradient had tightened..NOT a TD. *repeats* What a hoot!
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4195. IKE
Quoting Hurricane4Lex:


Takes it right over here, through Paxton and Laurel Hill,Fl....Florala,AL..up through sweet home Alabama....
Member Since: June 9, 2005 Posts: 23 Comments: 37860
4194. drj27
looks like a bay county and walton county storm
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4193. jipmg
what would a slower moving Bill mean in regards of the trough?
Quoting IKE:


We don't need rain or 40-50 mph winds. I've had close to 1 1/2 feet of rain since July 1st. Trees all over the place here. Usually a 40-50 mph wind puts branches down.



True, the rain can be bad in any tropical systems, but as far as the wind goes this is not much different than an afternoon thunderstorm.
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000
WTNT84 KNHC 160905
TCVAT4

FOUR WATCH/WARNING BREAKPOINTS/ADVISORY NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042009
500 AM EDT SUN AUG 16 2009

.TROPICAL DEPRESSION FOUR

FLZ001-002-003-004-005-006-008-012-014-015-018-027-028-034-
161500-
/O.NEW.KNHC.TR.W.1004.090816T0900Z-000000T0000Z/
500 AM EDT SUN AUG 16 2009

AL/FL-BORDER 30.30N 87.45W
SUWANNEE-RIVER-FL 29.30N 83.15W

$$

ATTN...WFO...MOB...TAE...
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4190. IKE
Quoting BajaALemt:
Wow...what a hoot, huh Ike? Hope this doesn't make us crazy busy today..LOL! I go into work at 5am soooooo....boyyyyyyyyyy howwwwwdy.


And you're in PC...correct? You'll be close to the COC....
Member Since: June 9, 2005 Posts: 23 Comments: 37860
4189. HadesGodWyvern (Mod)
Is starting to wonder if JMA will keep Maka's name.. I am confuzzled
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Quoting jipmg:
Carnival ship has reported a 45 mph sustained wind near TD 4


Yup... We discussed it on pg 75... specifically post, around post 3713..
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4186. KEEPEROFTHEGATE (Mod)
000
WTNT84 KNHC 160905
TCVAT4

FOUR WATCH/WARNING BREAKPOINTS/ADVISORY NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042009
500 AM EDT SUN AUG 16 2009

.TROPICAL DEPRESSION FOUR

FLZ001-002-003-004-005-006-008-012-014-015-018-027-028-034-
161500-
/O.NEW.KNHC.TR.W.1004.090816T0900Z-000000T0000Z/
500 AM EDT SUN AUG 16 2009

AL/FL-BORDER 30.30N 87.45W
SUWANNEE-RIVER-FL 29.30N 83.15W

$$

ATTN...WFO...MOB...TAE...


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Wow...what a hoot, huh Ike? Hope this doesn't make us crazy busy today..LOL! I go into work at 5am soooooo....boyyyyyyyyyy howwwwwdy.
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4184. HadesGodWyvern (Mod)
Joint Typhoon Warning Center

Tropical Cyclone Formation Alert (0600z 16AUG)
=============================================
An area of convection (94W) located at 11.2N 161.4E or 315 NM northeast of Pohnpei. Recent animted multispectral satellite imagery indicates that convection is starting to consolidate around a developed low level circulation center. The European Solution of the 2330z ASCAT Pass shows a much improved low level circulation center with strongest winds (20 knots) in the northwest and southeast quadrants. Additionally, a 2321z Composite METOPA Microwave image depicts convective bands starting to wrap into the low level circulation center from the northeast and southwest. Finally, animated water vapor imagery indicates that the system is in an area of low vertical wind shear with some poleward outflow into a tropical upper tropospheric trough located to the northeast.

Maximum sustained winds near the center is 15-20 knots with a minimum sea level pressure of 1007 MB. Due to the increased consolidation of the low level circulation center, the potential for this disturbance to form into a significant tropical cyclone within the next 24 hours is UPGRADED TO GOOD.
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4183. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #1
TROPICAL DEPRESSION (MAKA)
15:00 PM JST August 16 2009
=========================================

SUBJECT: Tropical Depression Near Wake Island

At 6:00 AM UTC, Tropical Depression, Former Maka (1008 hPa) located at 16.1N 174.0E has 10 minute sustained winds of 30 knots with gusts of 50 knots. The depression is reported as moving norteast at 11 knots

Forecast and Intensity
======================
24 HRS: 17.8N 175.0E - 35 knots (CAT 1/Tropical Storm)
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does anyone have a link for the advisories where I can see the region. I read the printed advisory but it's after 5 and I've been up all night and I can't picture it right now.
Thanks
JoJo
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4181. IKE
Quoting KEEPEROFTHEGATE:
as ws would say ike have ya got your flashlights and batteries out yet


LOL...that's why I'm Wal-Mart bound....place will be dead at 6 am.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
4180. HadesGodWyvern (Mod)
National Hurricane Center
Tropical Cyclone Advisory #17
SEVERE TROPICAL CYCLONE GUILLERMO (EP102009)
9:00 AM UTC August 16 2009
====================================

At 6:00 AM UTC, Hurricane Guillermo (973 hPa) located at 19.8N 137.4W or 1000 NM east of Hilo, Hawaii has sustained winds of 85 knots with gusts of 105 knots. The cyclone is reported as moving west at 13 knots.

Hurricane-force Winds
=====================
35 NM from the center

Gale/Storm-force Winds
================
105 NM from the center

Forecast and Intensity
======================
12 HRS: 20.3N 139.4W - 75 knots (SSHS-1 Cyclone)
24 HRS: 21.2N 142.1W - 60 knots (Tropical Storm)
48 HRS: 23.3N 147.5W - 40 knots (Tropical Storm)
72 HRS: 26.0N 153.0W - 30 knots (Tropical Depression)
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4179. jipmg
convection over TD 4 now looks perfectly cemetrical, with the anticyclone over head, it might erupt before sun rise
just remember Humberto07 and Marco08.... "Claudette" looks like a combo of the 2
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4177. IKE
Quoting weatherblog:
It's gonna be a 50 mph tropical storm. The only thing I'm expecting is rain and some thunderstorms-- not something uncommon in Florida. I'm still thinking this is nothing to worry about.

The real threat is Bill.


We don't need rain or 40-50 mph winds. I've had close to 1 1/2 feet of rain since July 1st. Trees all over the place here. Usually a 40-50 mph wind puts branches down.

Member Since: June 9, 2005 Posts: 23 Comments: 37860
I am going to catch some shut eye before day break comes...
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Quoting KEEPEROFTHEGATE:
as ws would say ike have ya got your flashlights and batteries out yet

Haha, I should be going to sleep right about now...
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4174. KEEPEROFTHEGATE (Mod)
as ws would say ike have ya got your flashlights and batteries out yet
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4173. HadesGodWyvern (Mod)
interesting the florida disturbance strengthened into a deep depression
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4172. IKE
FORECAST VALID 17/0600Z 31.0N 86.7W...INLAND
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 0NE 60SE 0SW 0NW.


Here in Defuniak Springs,FL....I'm at 30.7N and 86.1W....

Those coordinates are within 35 miles of me...and I'm on the WNW side of DFS.

Center may cross right over here.
Member Since: June 9, 2005 Posts: 23 Comments: 37860
It's gonna be a 50 mph tropical storm. The only thing I'm expecting is rain and some thunderstorms-- not something uncommon in Florida. I'm still thinking this is nothing to worry about.

The real threat is Bill.
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4170. KEEPEROFTHEGATE (Mod)
Quoting Weather456:
wow

wow is a understatement more like amazing truly amazing now if one more pops up with the area off africa that will be the group of four
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Quoting jipmg:
Carnival ship has reported a 45 mph sustained wind near TD 4


Wouldn't surprise me to find a special advisory at some point within the next couple of hours saying we have Claudette.
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4168. jipmg
Carnival ship has reported a 45 mph sustained wind near TD 4
Quoting IKE:
Guess I'll head to Wal-Mart in a couple of hours and beat the rush.....


Yup people are in for a rude awakening
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4166. IKE
Guess I'll head to Wal-Mart in a couple of hours and beat the rush.....
Member Since: June 9, 2005 Posts: 23 Comments: 37860
Quoting Joanie38:


Good morning Stephanie...my neighbor..:) I just hope we don't get one this year at all.. we had enough last year...


I gotta agree there. And the year before and 2006 was a very good year :), and the year before that...Lol. I'm tired.
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Puerto Rico now under a Tropical Storm watch.
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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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