TD 2 nearly dead; African disturbance 90L gathering strength

By: Dr. Jeff Masters , 2:38 PM GMT on August 13, 2009

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Tropical Depression Two is near death, but is still worth watching. The dry, Saharan air to the north and west of the depression, combined with moderately high levels of wind shear of 15 - 20 knots, have almost completely destroyed all of TD 2's heavy thunderstorms. Satellite loops of the storm show a well-formed circulation, but almost no heavy thunderstorm activity.

Wind shear over TD 2 is expected to remain in the modereate range, 10 - 20 knots, over the next five days. Sea Surface Temperatures (SSTs) are 27°C, but will warm to 28°C three days from now. There is plenty of dry, stable air from the Saharan Air Layer (SAL) to to TD 2's north and west that will continue to cause the storm problems. The relatively cool SSTs and dry air mean that TD 2 will not be able to intensify quickly, and some of the models indicate the TD 2 may get destroyed in the next day or two. However, several models still predict TD 2 will become a tropical storm. The HWRF model predicts TD 2 will become a hurricane five days from now, but this seems unlikely given the dry air and relatively high wind shear affecting the storm.


Figure 1. Tropical Depression Two (left side of image) and tropical wave 90L (right side of image).

African tropical wave 90L
A strong tropical wave with a large circulation and plenty of heavy thunderstorm activity is a few hundred miles south of the Cape Verdes Islands, off the coast of Africa. NHC dubbed this disturbance 90L this morning. This morning's QuikSCAT pass shows that 90L has a very large circulation, and top winds of about 30 mph. Satellite imagery from the European METEOSAT satellite show that the heavy thunderstorms associated with 90L are in two major bands, to the north and to the south of the center. There is no heavy thunderstorm activity near the center yet, and this would have to happen before 90L can be named Tropical Depression Three. Water vapor imagery shows that since 90L is forming several hundred miles south of the dry air of the Saharan Air Layer (SAL), the storm should not be affected by dry air and dust as much as Tropical Depression Two has been. Wind shear is about 20 knots over 90L, and is forecast to remain in the moderate range, 10 - 20 knots, over the next five days. Sea Surface Temperatures are about 28°C, and will remain in the 27 - 28°C range the next five days, which are high enough above the 26°C threshold for tropical cyclone formation to allow some slow development to occur. The GFS and ECMWF models continue to predict the development of this wave, though they are now less aggressive about intensifying it than they were in earlier runs. The consensus among the reliable HWRF, GFDL, GFS, and ECMWF models is to bring 90L to point near or just north of the northernmost Lesser Antilles Islands 6 - 8 days from now. The storm could be at hurricane strength by then, as forecast by the SHIPS intensity model.

I'll have an update Friday morning.

Jeff Masters

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Quoting atmoaggie:
The stormno forecast office, parked on the Orleans Ave canal:


LOL!
Member Since: Posts: Comments:
Ex Td2 would be basically known what is known as a vort/cane /storm, unless the system can expand and grow any.

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2135. Rodek
I usually lurk but post on rare occasions. I wanted to take a second to thank everyone for keeping the information flowing throughout the day and night on this blog. Without you, I'd be bored and ill-informed.

Now, a couple of questions.

How old are the models that are used to attempt to predict possible storm tracks?

Also, are there plans for new, more accurate systems in the future?
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2132. KEEPEROFTHEGATE (Mod)
549

WHXX01 KWBC 140032

CHGHUR

TROPICAL CYCLONE GUIDANCE MESSAGE

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL

0032 UTC FRI AUG 14 2009



DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.

PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE

AND SUBTROPICAL CYCLONE INFORMATION.



ATLANTIC OBJECTIVE AIDS FOR



DISTURBANCE INVEST (AL902009) 20090814 0000 UTC



...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...

090814 0000 090814 1200 090815 0000 090815 1200



LAT LON LAT LON LAT LON LAT LON

BAMS 11.5N 24.0W 12.3N 26.8W 13.1N 30.4W 13.4N 34.8W

BAMD 11.5N 24.0W 11.6N 26.8W 11.4N 29.5W 11.3N 32.3W

BAMM 11.5N 24.0W 11.9N 26.8W 12.3N 29.7W 12.7N 33.2W

LBAR 11.5N 24.0W 11.6N 26.4W 12.0N 29.4W 12.2N 32.9W

SHIP 25KTS 29KTS 37KTS 48KTS

DSHP 25KTS 29KTS 37KTS 48KTS



...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...

090816 0000 090817 0000 090818 0000 090819 0000



LAT LON LAT LON LAT LON LAT LON

BAMS 13.4N 39.6W 12.8N 49.3W 12.0N 57.3W 10.5N 63.6W

BAMD 11.3N 35.2W 12.3N 41.2W 14.4N 47.3W 16.6N 53.4W

BAMM 12.9N 37.2W 12.7N 45.2W 12.3N 51.0W 13.7N 55.0W

LBAR 12.6N 36.9W 13.1N 45.5W 13.5N 50.2W .0N .0W

SHIP 60KTS 77KTS 86KTS 93KTS

DSHP 60KTS 77KTS 86KTS 93KTS



...INITIAL CONDITIONS...

LATCUR = 11.5N LONCUR = 24.0W DIRCUR = 270DEG SPDCUR = 7KT

LATM12 = 11.6N LONM12 = 22.5W DIRM12 = 275DEG SPDM12 = 6KT

LATM24 = 11.4N LONM24 = 21.1W

WNDCUR = 25KT RMAXWD = 60NM WNDM12 = 25KT

CENPRS = 1009MB OUTPRS = 1012MB OUTRAD = 180NM SDEPTH = M

RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM



$$

NNNN
Member Since: July 15, 2006 Posts: 178 Comments: 55976
2131. Skyepony (Mod)
Looks like one spot in NE Dominican Republic that has had near 4inches of rain in the last 3 hrs.
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The stormno forecast office, parked on the Orleans Ave canal:
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2128. KEEPEROFTHEGATE (Mod)
933

WHXX01 KWBC 140030

CHGHUR

TROPICAL CYCLONE GUIDANCE MESSAGE

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL

0030 UTC FRI AUG 14 2009



DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.

PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE

AND SUBTROPICAL CYCLONE INFORMATION.



ATLANTIC OBJECTIVE AIDS FOR



DISTURBANCE TWO (AL022009) 20090814 0000 UTC



...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...

090814 0000 090814 1200 090815 0000 090815 1200



LAT LON LAT LON LAT LON LAT LON

BAMS 14.2N 39.0W 14.6N 40.9W 15.1N 42.8W 15.7N 45.7W

BAMD 14.2N 39.0W 14.8N 41.4W 15.6N 43.9W 16.7N 46.7W

BAMM 14.2N 39.0W 14.4N 40.9W 14.8N 43.0W 15.2N 45.7W

LBAR 14.2N 39.0W 14.4N 41.0W 15.1N 43.5W 15.9N 46.5W

SHIP 25KTS 26KTS 29KTS 31KTS

DSHP 25KTS 26KTS 29KTS 31KTS



...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...

090816 0000 090817 0000 090818 0000 090819 0000



LAT LON LAT LON LAT LON LAT LON

BAMS 17.0N 49.6W 20.5N 58.8W 24.6N 66.4W 28.8N 69.9W

BAMD 18.1N 49.7W 21.2N 55.3W 23.0N 59.9W 23.0N 64.4W

BAMM 16.0N 49.0W 17.7N 57.4W 20.1N 66.0W 22.9N 72.4W

LBAR 16.8N 49.9W 19.0N 57.1W 20.9N 64.2W .0N .0W

SHIP 34KTS 39KTS 43KTS 45KTS

DSHP 34KTS 39KTS 43KTS 45KTS



...INITIAL CONDITIONS...

LATCUR = 14.2N LONCUR = 39.0W DIRCUR = 270DEG SPDCUR = 8KT

LATM12 = 14.0N LONM12 = 37.2W DIRM12 = 278DEG SPDM12 = 7KT

LATM24 = 14.1N LONM24 = 35.6W

WNDCUR = 25KT RMAXWD = 40NM WNDM12 = 25KT

CENPRS = 1008MB OUTPRS = 1012MB OUTRAD = 150NM SDEPTH = M

RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM



$$

NNNN
Member Since: July 15, 2006 Posts: 178 Comments: 55976
My personal opinion 90L could become a very dangerous storm, sure hop eit stays clewar of the NW Caribbean & all other land masses, Gilbert & Dean comes to mind regarding track.
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Quoting stormhank:
Hi everyone...does anyone have a good link for eastern atlantic satellite ? thanks so much..


Link
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Quoting stormpetrol:
looking sad for former td2 looks like the coc/llc might even be losing it , of course nothing over til its over

I am not giving up on ex-TD2 yet not until 11 am tomorrow
Member Since: June 13, 2009 Posts: 2 Comments: 12716
Quoting HurricaneJoe:


You sure are confident about this...you've been predicting it for days.


He has actually been predicting it for years. Stormtop is to the Gulf what Bastardi is to the NE.
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Has 90L sped up or slowed down in forward speed?
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I know it's way to early to tell how strong 90L will become, or what path it will take; however, from what I can see, this looks to be a land lover system. Someone will more than likely feel the effects.
It looks like mother nature could make up for the late start to the hurricane season this year.
Not to be selfish, but I hope the Florida Keys are spared for yet another year...I never want to re-live another Wilma event. Surge sucks! I lost everything in Wilma; and she wasn't even a major wind event here!
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Quoting stormno:
this is a special weather statement issued by my weather office for la mississippi and alabama..people need to to just keep tuned to your weather officials this weekend..there is a very good chance with the ssp falling in the northern gom and sst as high as 95 degress something could form and strengthen rapidly...so im asking everyone who live on the northern and ne gom to keep abreast of the weather information..my data out of my office indicated to me conditions or ripe for a depression to form late sat or sunday..im giving this forecast a 60% chance we will be dealing with anna in the gom sat or sunday..please stay tuned and i will broadcast the minute i see any threatening weather conditions for the gulf coast...i will be getting new data shortly after 2am ..i want to stress its nothing to worry about now its just something i want everyone to watch over the weekend...this has been a special weather statement issued by stormnos weather office out of new orleans..Stormno


You sure are confident about this...you've been predicting it for days.
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Quoting stormno:
this is a special weather statement issued by my weather office for la mississippi and alabama..people need to to just keep tuned to your weather officials this weekend..there is a very good chance with the ssp falling in the northern gom and sst as high as 95 degress something could form and strengthen rapidly...so im asking everyone who live on the northern and ne gom to keep abreast of the weather information..my data out of my office indicated to me conditions or ripe for a depression to form late sat or sunday..im giving this forecast a 60% chance we will be dealing with anna in the gom sat or sunday..please stay tuned and i will broadcast the minute i see any threatening weather conditions for the gulf coast...i will be getting new data shortly after 2am ..i want to stress its nothing to worry about now its just something i want everyone to watch over the weekend...this has been a special weather statement issued by stormnos weather office out of new orleans..Stormno


Always glad to see your update.
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looking sad for former td2 looks like the coc/llc might even be losing it , of course nothing over til its over
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Quoting DM21Altestic:
are the UKMET and NOGAPS not developing it?

So far this season, NOGAPS has been the antithesis of the CMC...develops nothing. (So far, that is)
And nothing much has happened...so NOGAPS has done well with our lack of development, actually.
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That Hispanola system is hammering Haiti with heavy rains right now (again). The GOM is overheated right now, a result of no tropical activity over it for the past two and a half months. If 90L or Ana can track into the Gulf, you've got a quick cat. 5. It could track north of the Greater Antilles without hitting land, so it could strengthen quickly while still flooding Haiti. Ugh.
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Quoting dcoaster:
Just going back through some of the comments the past few days. Is it just me or does anyone else find it very amusing/saddening to see people saying a storm 3000 miles away is going to hit location X because one model said so?


People tend to trust the models alot...anything after 120 hours is speculation, IMO.
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Quoting HurricaneJoe:
Give it time, it just recently came off of the coast.just the usual, it has not become a td yet, but everyone wants a track. i wish i had a nickle for everytime that term will be used in the next week if it develops.
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Bob sounds very concerned about 90L on his show.
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DR & Haiti taking a soaking usual for real sad, all it takes is plenty rain and they die in Haiti, sometimes is just sames like the poor are always dealt a bad hand in life, makes ones wonder at times.
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Just going back through some of the comments the past few days. Is it just me or does anyone else find it very amusing/saddening to see people saying a storm 3000 miles away is going to hit location X because one model said so?
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Quoting HurricaneJoe:
Give it time, it just recently came off of the coast.
That's my point. Things change from hour to hour. No disrepect to anyone here but if everyone here wrote a city on a piece of paper, sealed it, mailed it to a different location, then after this thing was over only 1-100 maybe would be closea t this point. But it is fun to guess.
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Quoting Drakoen:


Drak or Drakoen is not even my real name.

Can you imagine all the time a certain someone has spent looking through all of the phone books he could lay his hands on? You just ruined his decade.
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Quoting PcolaDan:

A Count from Romamia?
LOL
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2100. aquak9
drakoen..I think we all knew that Drakoen was not your real name....
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Quoting Drakoen:


Who would name their child Drak

A Count from Romamia?
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2098. Drakoen
The GFDL and HWRF look to be just as fast as the GFS only further north. Definitely bears watching.
Member Since: October 28, 2006 Posts: 57 Comments: 30814
StormW is on the Barometer Bob Show right now!!
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Quoting stormhank:
Hi everyone...does anyone have a good link for eastern atlantic satellite ? thanks so much..


Link
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2095. Drakoen
Quoting aquak9:


No Way!!!


Who would name their child Drak
Member Since: October 28, 2006 Posts: 57 Comments: 30814
Hi everyone...does anyone have a good link for eastern atlantic satellite ? thanks so much..
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2093. aquak9
Quoting Drakoen:


Drak or Drakoen is not even my real name.


No Way!!!
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I'm out, take care...
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Quoting DM21Altestic:
So what category do you guys think this system will eventually end up peaking as?

I say Category Four.
Quoting DM21Altestic:
So what category do you guys think this system will eventually end up peaking as?

I say Category Four.
lol there will be no trpical development in the atlantic this season 0-0-0
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Give it time, it just recently came off of the coast.
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StormW I like the runs myself. Yesterday it was heading for Mobile Bay. Now PCB, Fl. Maybe next further East, and so on. We know these models always change from run to run. So everyone from TX to ME need to watch for the time being
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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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