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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There have been so many hurricanes over the years that anyone can find a track that matches their current thinking.
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damn the models are all clustered on this one, this, is not good. its getting its act together as well. 90L i mean
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3484. flsky
Quoting BenBIogger:

Please explain why you're showing us these maps - I don't see the significance. Thanks.
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3483. java162
Quoting Stormchaser2007:

No where is off the hook yet.
\


its still a wait and see game until it develops into something more organised so the models can get a beter grasp of the situation
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Guess who.

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Quoting mikatnight:
1928 Okeechobee hurricane:



That would be a direct hit on me.
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Quoting java162:


aight. so the islands arn't off the hook yet

No where is off the hook yet.
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Td2 is defiantly getting its act together first time I have seen action in daytime. Maybe its not a vampire.
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Quoting BayouBorn1965:


This is very interesting! Guess I have a week to get ready. Does this model give you any idea of what CAT strength this will be?
CrownWeather stated an expected Cat 3 around the Leeward Islands next Wednesday...
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Could someone post the times for the model runs?

Thanks!
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1926 Great Miami hurricane:

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Good morning

Here is the big challenge for Ex TD2. From the WV image you will see that it is surrounded by extremely dry air. In particular, there is a significant "tongue" of dry air to the South that is undercutting any moist inflow from that direction and to the West there is only a small barrier of moisture between the low center and bone dry air.

While there is a current resurgence of convection it will soon be hitting the peak heat of the day out there in the next few hours which may put a damper on the comeback attempt.

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Quoting TampaSpin:
This is a big time OUCHY!



Tampa....can you post a link what you posted??
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Quoting mikatnight:
1928 Okeechobee hurricane:




This track is VERY plausible.
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Quoting TampaSpin:
OLD TD2 is better organized than 90L.....i believe we will have Ana and Bill coming almost the same time....and they are far enough apart to possibly be ok now.....as TD2 has been out running 90L


I agree with that only because 90Ls LLC is slightly elongated.
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3470. szqrn1
TS...I just noticed the "above me " that you posted..sorry and thanks!
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Member Since: March 19, 2009 Posts: 0 Comments: 1421
3465. hurricanehanna 1:26 PM GMT on August 14, 2009
For those who are new to this blog (or just lurkers) Stormjunkie and TampaSpin have awesome information on their sites, with up to the date images, maps, etc..... really keeps you "in the know" when things start rockin'


absolutly!!! along with a hand full of others...
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1928 Okeechobee hurricane:

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Quoting BayouBorn1965:


This is very interesting! Guess I have a week to get ready. Does this model give you any idea of what CAT strength this will be?


At the end in the GOM my best guess that would appear to be at least a CAT3 maybe a 4 then oh no...five.
Member Since: September 2, 2007 Posts: 179 Comments: 20448
For those who are new to this blog (or just lurkers) Stormjunkie and TampaSpin have awesome information on their sites, with up to the date images, maps, etc..... really keeps you "in the know" when things start rockin'
Member Since: September 5, 2007 Posts: 0 Comments: 3488
3464. java162
Quoting Chucktown:


But trending south in the last few runs of the GFS


aight. so the islands arn't off the hook yet
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wow....the 06gfs does not look good at all....
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OLD TD2 is better organized than 90L.....i believe we will have Ana and Bill coming almost the same time....and they are far enough apart to possibly be ok now.....as TD2 has been out running 90L
Member Since: September 2, 2007 Posts: 179 Comments: 20448
TampaSpin you have been flagged and reported for posting that scary image! j/k Seriously though - that is scary.
Member Since: April 26, 2009 Posts: 3 Comments: 3667
The 1947 Ft. Lauderdale/New Oreans Hurricane (top winds at Pompano Beach, FL landfall were 155 mph):

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Quoting TampaSpin:
This is a big time OUCHY!



This is very interesting! Guess I have a week to get ready. Does this model give you any idea of what CAT strength this will be?
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3458. szqrn1


seein if this works....
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Quoting java162:
the official model is taking invest 90 above the islands!!!!


But trending south in the last few runs of the GFS
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Quoting szqrn1:


I am talking about where you actually "see" the system enlarge and roll in...ya know what I am talking about? Not just the lines.


Everything you need is at my Weather Links TAb.

Also StormJunkie.com has a simalar link that does the same......give him some PR!
Member Since: September 2, 2007 Posts: 179 Comments: 20448
3455. eddye
where does that model showit hiting gfsx
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Quoting StormW:
Good morning!

Thank all of you that participated in the Barometer Bob show last night.

New update hot off the press.

Thanks!

TROPICAL WEATHER /90L/ SYNOPSIS AUGUST 14, 2009 ISSUED 9:00 A.M. EDT


Thanks for the update Storm - but could ya provide Prozac with that? lol
Hope everyone is making their list and checking it twice at this point....
Member Since: September 5, 2007 Posts: 0 Comments: 3488
3453. szqrn1
TS I don't know how to put ans image in here or I would show you what I am talking about.... but I am sure you know
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3452. Skyepony (Mod)
Quoting CaneWarning:


Look at the area off of Tampa right now... Huge area of rain. I wonder if it will make it onshore.


Looks like FL is in for some rain today.
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3451. jipmg
TD 2 is making a comeback, this time for real, no shear going to blow its storms off now..

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Quoting TampaSpin:
This is a big time OUCHY!



That blasted model has been kickin' Florida butt all week...
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Quoting ALCoastGambler:
How many hours out is that Tampa? And Good morning


10 days
Member Since: September 2, 2007 Posts: 179 Comments: 20448
3448. java162
the official model is taking invest 90 above the islands!!!!
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3447. szqrn1
Quoting TampaSpin:


Just above you.


I am talking about where you actually "see" the system enlarge and roll in...ya know what I am talking about? Not just the lines.
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Quoting seflagamma:



Well that is great!
Alot of folks call Aug 19th their birthday.
I think it has something to do with "holiday parties" in Late November and December !

So we will watch the storms next Wednesday together? LOL


LOL, mines a day before yours.
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EXTD2

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3443. ackee
what the chance that XTD#2 becomes Ana before 90L think the gender race is on
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Good Morning Everyone...from South Fla..
Thanks for the update StormW..very helpful as always.. Some seaons in the past, we saw storms build rapidly, far out in the Atlantic and fail to hold their footprint of being strong storm for a great length of time.. I wonder if 90L/Ana..will do just that?
G'day all...
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Quoting TampaSpin:
This is a big time OUCHY!



Ew.
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Quoting szqrn1:
TWC this morning showed the model run bringing 90 up to central Gulf Coast. I looked at the FSU site that shows the models but it does not take it out that far in time.

Need a good link to the model run that they had on...and all the models... Thanks


Just above you.
Member Since: September 2, 2007 Posts: 179 Comments: 20448
tampaspin....nope that don't look good at all...that will be more than just an "ouchy" for sure....
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Quoting TampaSpin:
This is a big time OUCHY!

How many hours out is that Tampa? And Good morning
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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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