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 Weather456:
The circulation of 90L remains broad but much tighter than this morning indicating it was organizing throughout the day



It's really only elongated over a 40 mile stretch. 99L/TD2 was similarly elongated a couple of days ago.
Member Since: September 22, 2005 Posts: 18 Comments: 2315
1936. IKE
Quoting ALCoastGambler:
Ike knows I respect him. He knows he is welcome here anytime. Just bring the beer. I'll supply the BBQ


LOL...

Looks like convection is firing up a little near the COC of 90L...Link
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Absolutely huge.

One of the biggest waves Ive seen since 2007.

Looks like the anticyclone continues to reposition itself over the LLC.
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Actually if you're near the AL coast we're neighbors now. Recently moved to just north of mobile.
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Quoting SavannahStorm:


Wow, that's quite, um... specific, for a over a WEEK AWAY.

We will not know what impact 90l will have on the CONUS until it gets near the Antilles, and even then we won't have good certainty until 3 days out.
im just saying what the experts are saying.
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Guys, be careful...I just cleared 7 trojans off of my system and I'm pretty sure I got them off WU during the past day. This page has been freezing for me all through the day, it has to be the ads that's doing it.
Member Since: July 30, 2007 Posts: 76 Comments: 4063
Don't forget everybody Barometer Bob show tonight at 8. we will be talking about current tropical activity and the 5th anniversary of hurricane charley

irc.hurricanehollow.org
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Quoting VAbeachhurricanes:


ur psychic?
i sure am, lol, i doubt very much that the NHC will kill it off if they knew it would regenerate, it will make the NHC look bad, and they hate that.
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The circulation of 90L remains broad but much tighter than this morning indicating it was organizing throughout the day

Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting VAbeachhurricanes:


ur psychic?
Thanks. I thought he was God.
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Quoting ALCoastGambler:
Now I would think someone like SOUTHALWX would be on my side...lol

southal being no exagerration. a town less than 10 minutes from here is literally called florala aka florida/alabama .. You could just as easily change my post name to northflwx and be nearly as accurate =P
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Ike knows I respect him. He knows he is welcome here anytime. Just bring the beer. I'll supply the BBQ
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1924. Patrap
..."I gotta tell ya folks,the tropics are really ramping up in the Atlantic..,check out Patrap"s Blog on Hurricane Preparation on the wunderground.com"..,

..Back to you guys in the Studio"...

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Quoting canesrule1:
I heard in some news station that 90L has the possibility to go in through around Homestead and exit through Orlando, as in doing the curve over Florida.


Wow, that's quite, um... specific, for a over a WEEK AWAY.

We will not know what impact 90l will have on the CONUS until it gets near the Antilles, and even then we won't have good certainty until 3 days out.
Member Since: September 22, 2005 Posts: 18 Comments: 2315
Quoting canesrule1:
Can u stop with the remnant low of 02L, its not going to generate, sheesh!


ur psychic?
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Quoting cyclonekid:
Interesting Run.

CMC Model: Watch out Houston, TX!!

Dang CMC keeps wanting to take us out! Heck, we need rain and all, but I'm thinking most of the people with blue tarps would rather the CMC just boogie that thing somewhere else :-P.
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Quoting IKE:


A lot of folks up here in the panhandle call it L A....lower Alabama..I live 15 miles from the state line....

Besides the latitude, is there really such a place as upper Alabama? (j/k)
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Quoting DM21Altestic:

Fay says hi.
lol, yup, very true!
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Quoting KEEPEROFTHEGATE:
456 you get my email i figure did it work



yea thanks, bu I will reply later on.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting SouthALWX:
well if u draw a line sout from dothan its pretty near to the LA region =] )There'a a joke here that The panhandle is simply part of bama. Here being at my parents house in south central AL on the fl/al line. Maybe the joke carries over there too. I know they dont consider themselves the same as say ppl from miami orlando or other peninsula cities.
Now I would think someone like SOUTHALWX would be on my side...lol
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Quoting wunderkidcayman:

yes IT dose have a chance it just needs a good D-MAX but already it is starting to organize
maybe but chances are slim, sorry if i was mean, it's been a crazy day.
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Quoting Vortex95:
Guys is there was way to find the average temperature in Hallendale, Florida (Highs, and Lows) for the last month.


On this site. Link
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Quoting WPBHurricane05:


Both started off big but if I remember, Ike was pretty small when it was a cat 4.


and that tells you 90L current size is irrelevant to its long term future...

it would slow to organize in the near term
Member Since: July 24, 2005 Posts: 407 Comments: 19076

TD2

90L

AOI
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Quoting Weather456:
Pre Ike



90L



they look very similar
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Our local mets say we have to watch this closely. My biggest fear for myself would be that it crosses over Tampa after a hit on the east coast. Storms can still do significant damage that way.
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1908. IKE
Quoting CaneWarning:


Those of us living in the Florida peninsula commonly refer to the Florida panhandle as Lower Alabama...


A lot of folks up here in the panhandle call it L A....lower Alabama..I live 15 miles from the state line....
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Quoting Weather456:
Pre Ike



90L



No comment.. wow.
Member Since: July 8, 2005 Posts: 259 Comments: 23590
I heard in some news station that 90L has the possibility to go in through around Homestead and exit through Orlando, as in doing the curve over Florida.
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Quoting stormwatcherCI:
Is there any chance TD2 gets more organized overnight or is it completely kaput ?

yes IT dose have a chance it just needs a good D-MAX but already it is starting to organize
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well if u draw a line sout from dothan its pretty near to the LA region =] )There'a a joke here that The panhandle is simply part of bama. Here being at my parents house in south central AL on the fl/al line. Maybe the joke carries over there too. I know they dont consider themselves the same as say ppl from miami orlando or other peninsula cities.
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Quoting canesrule1:
can u give me the link to that chart, thanks a lot.


Late model intensity.
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Quoting ALCoastGambler:
I know that but we in Lower Alabama would rather not claim Ike and yourself....LOL j/k


I'm in Tampa - not part of Lower Alabama.
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Quoting Weather456:
Pre Ike



90L



Both started off big but if I remember, Ike was pretty small when it was a cat 4.
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QUICK UPDATE POSTED:
South Florida StormWatch
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Quoting CaneWarning:


Those of us living in the Florida peninsula commonly refer to the Florida panhandle as Lower Alabama...
I know that but we in Lower Alabama would rather not claim Ike and yourself....LOL j/k
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---
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1895. KEEPEROFTHEGATE (Mod)
456 you get my email i figure did it work
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Quoting DM21Altestic:
So the most naturally beautiful woman on WU has logged on. Hi to you. :)

Direct hit in Tampa? I doubt that.
Sideswiping? It's always possible. But it could go out to sea or even be a Caribbean tracker. It's way too early to tell. Don't listen to the wishcasters.
Must be Presslord
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Quoting wunderkidcayman:
according to the AVN ir sat convection is starting to go around the COC of ex-TD2


Link
Can u stop with the remnant low of 02L, its not going to generate, sheesh!
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Let me point out that, given the apparent size of this system, the direct line will not be an issue. If you end up anywhere near the cone, be prepared.
Member Since: September 22, 2005 Posts: 18 Comments: 2315
Pre Ike



90L

Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting ALCoastGambler:
Ummmm I think you need a map. Panama City Beach, Fl is nowhere near Lower AL


Those of us living in the Florida peninsula commonly refer to the Florida panhandle as Lower Alabama...
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Quoting weathersp:


Not funny... even though some of us know its a joke... Some lurkers here may have thought you wern't kidding...

Please consider your actions before you post.


I'm not joking. You should always be prepared!
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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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