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 IKE:
Claudette will be here by 10 am CDST...maybe by 7...based on radar trends....

I do see how this is really going to freak alot as they will not know about it till they wake up and its just offshore..but..not like anyone can do anything..cant have loudspeaker in a blimp saying "TS IS COMING THIS WAY RUNN!!" lol..Not really anyones fault..nature just wanted to get some payback i guess..thank God it wont be a strong hurricane..
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Quoting HurricaneFCast:

? They are satellite-based estimates of intensity, how are they following the NHC? (I don't mean to sound like I'm attacking your statement, I'm just trying to figure out what you mean, that's all.)
Does the NHC post Dvorak #'s somewhere every half-hour? I use CIMSS.


Look at: Scene Type - that will tell you.

UW - CIMSS
ADVANCED DVORAK TECHNIQUE
ADT-Version 7.2.3
Tropical Cyclone Intensity Algorithm

----- Current Analysis -----
Date : 16 AUG 2009 Time : 091500 UTC
Lat : 27:45:13 N Lon : 83:55:57 W


CI# /Pressure/ Vmax
2.0 /1009.0mb/ 30.0kt


Final T# Adj T# Raw T#
(3hr avg)
2.0 2.0 2.0

Latitude bias adjustment to MSLP : +0.0mb

Center Temp : -45.6C Cloud Region Temp : -32.7C

Scene Type : USER DEFINED INITIAL CLASSIFICATION

Positioning Method : FORECAST INTERPOLATION

Ocean Basin : ATLANTIC
Dvorak CI > MSLP Conversion Used : ATLANTIC

Tno/CI Rules : Constraint Limits : NO LIMIT
Weakening Flag : OFF
Rapid Dissipation Flag : OFF

****************************************************

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4312. bcn
Any comment about Nicaragua/Honduras coast situation?
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4311. GatorWX
I don't know, these micro storms really puzzle me. This one really looks to be strengthening fast though. They're so much different than larger storms, At least we have it right off the coast on radar, satellites wont tell us much visually of whats going on if it strengthens very fast without growing much in area.
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JTWC said anything?
Member Since: August 23, 2008 Posts: 7 Comments: 5300
4309. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #2
TROPICAL DEPRESSION (MAKA)
18:00 PM JST August 16 2009
=========================================

SUBJECT: Tropical Depression Near Wake Island

At 9:00 AM UTC, Tropical Depression (1008 hPa) located at 16.3N 174.5E has 10 minute sustained winds of 30 knots with gusts of 50 knots. The depression is reported as moving east-northeast at 9 knots

Forecast and Intensity
======================
24 HRS: 18.1N 175.3E - 35 knots (CAT 1/Tropical Storm)

--
hmm east-northeast.. you don't say JMA. O_O
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4308. IKE
Claudette will be here by 10 am CDST...maybe by 7...based on radar trends....
Member Since: June 9, 2005 Posts: 23 Comments: 37858
2009 has now even managed to reach 1 on the ACE scale...
Member Since: August 23, 2008 Posts: 7 Comments: 5300
Quoting IpswichWeatherCenter:


Yeh - by the looks they are being updated manually, and they are simply following the NHC.

? They are satellite-based estimates of intensity, how are they following the NHC? (I don't mean to sound like I'm attacking your statement, I'm just trying to figure out what you mean, that's all.)
Does the NHC post Dvorak #'s somewhere every half-hour? I use CIMSS.
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FYI...The real props for calling TD4 first goes to this guy...

(AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA)


PREV DISCUSSION... /ISSUED 433 AM CDT SUN AUG 9 2009/


LONG TERM...
THE STALLING BOUNDARY COUPLED WITH DEEP MOISTURE SHOULD HELP KEEP
US IN A WET PATTERN BUT CAN PROBABLY TAPPER POPS BACK TO JUST
ABOVE NORMAL BY THAT TIME DUE TO SOME SLIGHTLY DRIER AIR INTRUDING
THE MID LEVELS. BY THE END OF THE WEEK...THE FCAST WILL HINGE
GREATLY ON WHAT THE TROUGH AXIS AND TROPICAL MOISTURE FEED DOES
AND GREATLY ON WHERE THEY ARE LOCATED. MODELS CONTINUE TO AGREE ON
AN UPPER LOW DEVELOPING AND CUTTING OFF FROM THE LONG WAVE TROUGH
AND SETTLE OVER DEEP SOUTH TEXAS. THIS WILL CAUSE UPPER SHEAR TO
WEAKEN DOWN STREAM OVER THE CENTRAL AND EAST GULF. WHY DOES THIS
CAUSE CONCERN? B/C THE DEEP MOISTURE AND OLD SFC TROUGH AXIS ARE
SUPPOSED TO BE LOCATED OVER THE NORTHERN GULF AND ANOTHER...BUT
THIS TIME...SIGNIFICANT EASTERLY WAVE WILL BEGIN TO ENTER THE
GULF. WE MAY NOT HAVE SEEN A LOT OF ACTIVITY SO FAR BUT IT IS
HURRICANE SEASON AND THIS SCENARIO BOTHERS ME BUT AM NOT CONFIDENT
ENOUGH AT THIS TIME TO CHANGE THE 6-7TH DAY OF THE FCAST.
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4304. IKE
Walton County/Okaloosa County,FL....


Tropical Storm Wind Warning in effect until 7 PM CDT Monday...
Flood Watch in effect from 1 PM CDT this afternoon through Monday morning...
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting HurricaneFCast:
One thing to keep an eye on is the AD #'s, as they update every half hour.


Yeh - by the looks they are being updated manually, and they are simply following the NHC.
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One thing to keep an eye on are the AD #'s, as they update every half hour.
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4301. eddye
it looks like bill could affect fl
Member Since: August 12, 2008 Posts: 0 Comments: 1204
4300. GatorWX
Quoting GatorWX:
I know it looks pretty dry on west side of system, but again it's very small, but again it's pretty tiny, so shouldn't be big factor to moisten it up enough to surround the eye and mini cdo.


duh!! just woke up
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Quoting IpswichWeatherCenter:


Yeh - my intensity forecast is what causes that.
There is no way Ana will stay a TS. Bill will intensify to the point where he gets guided into the Caribbean, but he will weaken in the Caribbean and basically die.


Bill isn't going into the Caribbean.

Member Since: August 23, 2008 Posts: 7 Comments: 5300
Looks like I need to batten down the hatches here in Carrabelle on the east quadrant. I don't think Destin has a worry unless it takes a very good jog west, not likely though. The damage I have seen after 40 something years of panhandle life is the tornado activity and heavy rains that can be spawned by a ts.

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4297. GatorWX
sorry, good morning everyone! What do you make of it Ike?
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4296. HadesGodWyvern (Mod)
hopefully it is still Maka, LOL

Guam NWS has it as Tropical Storm Maka
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4295. IKE
System is strengthening....look at the reds firing up....heavy rains....

Member Since: June 9, 2005 Posts: 23 Comments: 37858
ADT for TD4:

Link
Member Since: August 23, 2008 Posts: 7 Comments: 5300
Am I imaging it or has Ana shifted further to the South and now has her sites set on a different path?
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Quoting weatherblog:


Huhh??? Ana is not going out to sea and Bill is not going through the caribbean like Dean. LOL


Yeh - my intensity forecast is what causes that.
There is no way Ana will stay a TS. Bill will intensify to the point where he gets guided into the Caribbean, but he will weaken in the Caribbean and basically die.
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4291. GatorWX
I know it looks pretty dry on west side of system, but again it's very small, but again it's pretty tiny, so shouldn't be big factor to moisten it up enough to surround the eye and mini cdo.
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Quoting HadesGodWyvern:
Cotillion Ioke was still a tropical cyclone when it crossed the dateline

Maka was not a tropical cyclone, if that makes a difference


Ah, okay. Interesting, well the other outlets still name it as Maka despite the regeneration from its remnants, so they may just follow suit. Would make sense, anyhow.
Member Since: August 23, 2008 Posts: 7 Comments: 5300
4289. HadesGodWyvern (Mod)
grr JMA is taking too long to make a new advisory.
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4288. kachina
Good morning! I see that the tech folks are still sleeping - they've left Invest 90 and Invest 91 up on Wunderground's tropic page....according to them, we should be watching 5 storms....
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4287. HadesGodWyvern (Mod)
Cotillion Ioke was still a tropical cyclone when it crossed the dateline

Maka was not a tropical cyclone, if that makes a difference
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Hopefully Bill won't swing straight into Bermuda instead either.
Member Since: August 23, 2008 Posts: 7 Comments: 5300
4285. GatorWX
Panhandle folks, keep a close eye on td 4, it's looking very healthy and really appears to be strengthening rapidly. It looks to be developing very heavy convection around the center. Very steady intense bands around a psuedo eyewall on e side. This appears to be eerily similar to Humberto in '07, and sort of micro-storm. I wouldn't call it weak because regional pressures aren't dropping as it's wind field should and size should remain very small independent of strength. Wind shear is forecast to rise some from 5-10 kts to 10-15 kts tomorrow. This could slow it down a bit. Don't be surprised when later around we see a much better looking storm. It's great that we should be able to see basically the entire storms formation and track on radar. NHC may hesitate and take some time to really grasp the whole situation. These small strong storms are amazing at how quick they form from almost nothing and very quickly. I honestly believe this could be a hurricane by landfall and land interaction is not going t o affect it because of it size.
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4284. IKE
Quoting neonlazer:

Nice big fat blob, lol


Man...not good.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
4283. IKE
Islands are still in the cone, but....odds of a direct hit have decreased some....

Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting HadesGodWyvern:
Cotillion yup or whatever name JMA gives 01C


Wouldn't it be Maka?

When Ioke went into the pacific, it kept its name.

Uh, West Pacific that is.
Member Since: August 23, 2008 Posts: 7 Comments: 5300

Nice big fat blob, lol
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4280. HadesGodWyvern (Mod)
Cotillion yup or whatever name JMA gives 01C
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Quoting IpswichWeatherCenter:
This is my personal forecast:
(sorry if I double post - I got a bug on Safari)

Forecast as of 11:00 BST


Huhh??? Ana is not going out to sea and Bill is not going through the caribbean like Dean. LOL
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Quoting HadesGodWyvern:
A Tropical Storm Watch may be needed for Wake Island..



From Maka?
Member Since: August 23, 2008 Posts: 7 Comments: 5300
4277. HadesGodWyvern (Mod)
A Tropical Storm Watch may be needed for Wake Island..

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Quoting DanielPC:
Go to the A HREF=http://www.newsherald.comPanama City News Herald's site. I've been updating it for about 24 hours. 'Bout to take a nap for a bit, but we update ours more often.



Thanks....

glad to see 1 responsible news outlet.
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4275. IKE
Member Since: June 9, 2005 Posts: 23 Comments: 37858
This is my personal forecast:
(sorry if I double post - I got a bug on Safari)

Forecast as of 11:00 BST
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Go to the Panama City News Herald's site. I've been updating it for about 24 hours. 'Bout to take a nap for a bit, but we update ours more often.

[Simple HTML becoming a problem; definitely need some sleep. Night all.]

Quoting IpswichWeatherCenter:


They won't mention it on the TV, its too late to evacuate people however there website is taking years to load:

http://www.wjhg.com/unclassified/769277.html

http://www.wjhg.com/
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Forecast as of 11:00 BST
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4271. IKE
Quoting jasoniscoolman10:
WATCH OUT N.C AND NORTH.


Looks like the islands may be spared.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Is everyone ready for our dress rehersal...
remember this is a drill.... nothing but a drill... going to be a wet and windy drill...
in 04 we had some dress rehersals too.... then came Ivan...and i know where the eye was it was over our house....
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Y'all have fun watching this morning! Back after work!
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4268. HadesGodWyvern (Mod)
hmm wouldn't "Bill" end up between the east coast states and Bermuda
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It should be noted that in their discussion, NHC says that due to its small size TD 4 (or
"claudette") will likely affect only a small area near landfall location (apalachicola?).
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Quoting BajaALemt:
You guys want to know what's really funny? NWS in Tallahassee (which covers Gulf, Bay, and Walton Counties) doesn't even have a TSW up :)) :))


Unprepared much? Anyways goodnight good luck to you IKE and everyone else in Claudette's path. Remember stores open soon so get ready before the rush if you haven't

stay safe all ^_^
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4265. IKE
Quoting BajaALemt:
I just checked 7's website.....not even a banner


That's pathetic.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Hey everyone. Just woke up and saw probable Claudette coming into my friends in the Panhandle/Alabama regions. Good luck and stay safe later today!
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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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