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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Don't mention Hugo... I think there is some old theories about the SC coast and hurricanes on years that end in 9s.... Grace,59, Hugo,89, floyd,99, and there were storms in 69 and 79,although not as big...
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here comes $5 gas
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2835. Drakoen
Atlantic Sea Surface Temperatures:
Member Since: October 28, 2006 Posts: 57 Comments: 31660
Quoting JLPR:


yeah that one of the things I hate more xD
I may end up trying to turn the TV on if powers doesn't come back fast

Like with Jeanne's whoops and we were without power for awhile


Heck, yesterday many were left without power and it was just some rain and thunderstorms. Another Cat 3 like Georges... nah, I don't even want to think about that. O_o
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2833. Drakoen
Thanks for the awesome graphics on your site Ryan.
Member Since: October 28, 2006 Posts: 57 Comments: 31660
2832. JLPR
The GFS track is very similar to Georges track in 98

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This is not good......LOOK at the GOM it is like a time bomb ready to explode...32deg celisus..WOW

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Quoting Drakoen:
Katrina:




eeeeeeek
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i no this is way far out in time for saying this but i think any one from FL to LA needs too watch this this storm looks biger then IKE so evere one will be feeling this
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2828. RyanFSU
Here's a quick animation to show how the previous 15-GFS forecast runs have evolved over the past 3-4 days for 90L.



Other GFS/HWRF/GFDL/WRF maps
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Quoting JLPR:


I saw it better and I think it makes landfall between Ponce and Salinas on that run =\


Well, remember Hugo. Wasn't it supposed to graze the South? We all know how that ended up. Not good either way.
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2826. Drakoen
Katrina:
Member Since: October 28, 2006 Posts: 57 Comments: 31660
2825. 7544
45 frames done ok tip of fla first then the gulf 8th run for fla so far
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2824. JLPR
Quoting alpha992000:
Quoting JLPR:


Well that kinda takes away my tranquility =\


Thar, there goes my peace of mind. It's too early still, but I guess that gives me plenty of time to get my stomach ready for a couple of weeks of canned food and warm beverages. Ugh.


yeah that one of the things I hate more xD
I may end up trying to turn the TV on if powers doesn't come back fast

Like with Jeanne's whoops and we were without power for awhile
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where evere 90L is going to hit evere one is going to be feeling it this could be biger then IKE
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I'm not buying a GOM storm until I see much more consistency, but it may be starting a trend.

But, it seems the storm would first hit Florida before the GOM.
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2821. JRRP
Quoting reedzone:
I'm only up to 174 hours lol.. You guys are fast

me too
jejeje
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I'm still thinking this will be an East Coast event, not a GOM event. Lets let the models do there swaying back and forth, in 5-7 days, when it reaches the Islands, we will have a better idea what the track will be.
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Quoting Drakoen:
New Orleans hit on the GFS 00z


link?
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2818. JLPR
Quoting jurakantaino:

Yes ,very close to our shores,here in Puerto Rico, according to GFS.


I saw it better and I think it makes landfall between Ponce and Salinas on that run =\
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I've been home all week with an unpleasant summer sinus infection that corresponded with the hottest days of the summer. My house thermostat didn't go below 82 all Monday and Tuesday with the air on full blast. Thankfully, I have had the pleasure of reading all these posts, many I find informative, many I find witty and entertaining. It's going to be an interesting week indeed at my office coming up. I'm the public information officer for the local Dept. of Emergency Management. It is my job (among many, many others) to explain the dangers of storms to the community. I do press releases daily, but the tropical statements I do for EM are always the most complicated and require the most research. If I was eligible for overtime, which I'm not, imagine how much I'd get for reading this blog night and day, trying to gain insight and multiple perspectives. However, it is not about money, it is about the safety of my community and its residents. Go to Google Earth and look up Seaside Heights, New Jersey (08751). We are a barrier island with NO protection at all. In fact, this area used to be about 10 feet higher one hundred years ago, but the sand dunes were bulldozed, as they were considered valueless at that time, and were victims of exploitation: their destruction fueled by the need for motels and bungalows to house tourists, our main economic driving force. Only one tiny section of our town has a remnant of these dunes, and the difference is striking. Additionally, the location where my home is sits on top of the Old Cranberry Inlet (wikipedia it), which was formed and closed by hurricanes. If a big one comes this way, I'm gathering up my animals, my computers, my clothes and personal effects, the few pieces of antique furniture I have, my comfy, expensive bed, and will ride it out safely at my brother's house on the mainland. I wouldn't even bother to board up here. This is a rental, and anything I'd leave behind would be crap I couldn't care less about, and the physicality of the building is not my responsibility. Even if I boarded, chances are others would not, and wind would get into the complex regardless. If it all blows away, I guess I'll have to buy better furniture, and set up headquarters once again in another location. On the flip-side, I like where I live. I have nice neighbors, and have an oceanview from the right angle...stand on a box, crane your neck to see it, lol. I love to wake up and hear the ocean's roar and smell the salt air. I love it here, but always have known that I must realize for all the good I've enjoyed, it could all go "poof" faster than the current year TD2! My heart goes out to others around here, who do not have a plan, or the convenience of lots of nearby relatives to seek refuge. If it was terrible, I could stay with my brother for as long as I needed until I could re-establish a new locale. What would others do? That's what bothers me the very most. I'm not going to think about that tonight. The next five days are expected to be picture-perfect. My family is in the beach parking/shower/food & sundries concession business. It should be a banner weekend, and I guess I will be stockpiling as much cash as I can, for I might be needing it. Let's hope the Lord blesses and spares us.
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2816. GetReal
Drak the good thing about that last GFS model run striking NOLA is that there is a better than 90% chance it will not happen.... ATT

However it is interesting that there is no longer a forecasted trough along the east coast...

Just can't count on them in mid to late August.
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2815. 7544
Quoting reedzone:
I'm only up to 174 hours lol.. You guys are fast


same here only 30 frames lol but in the bahaamas so far
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2814. Drakoen
Quoting TampaSpin:


Drak the GFS has not really wavered to much on that track for the last several runs.


The GFS 12z wanted to send this thing riding up the eastern seaboard. No long range consistency. It's just for fun to look at the GFS that far out
Member Since: October 28, 2006 Posts: 57 Comments: 31660
Quoting JLPR:
150hrs 00z GFS



O_O



GFS has been forrescasting a Cat 3 cane over PR in August 20 over the past 4-5 days if this came true will be an amaizing performanse of this model. Thriler days ahead here at PR, Sadly.
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This is going to get nasty....really nasty possibly.
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Quoting JLPR:


Well that kinda takes away my tranquility =\


Thar, there goes my peace of mind. It's too early still, but I guess that gives me plenty of time to get my stomach ready for a couple of weeks of canned food and warm beverages. Ugh.
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Quoting Drakoen:



thats not good
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I'm only up to 174 hours lol.. You guys are fast
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Quoting Drakoen:
New Orleans hit on the GFS 00z


Drak the GFS has not really wavered to much on that track for the last several runs.
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no trough on 00z GFS
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2805. JLPR
Quoting jurakantaino:

Yes ,very close to our shores,here in Puerto Rico, according to GFS.


yep =\ not good
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Quoting JLPR:
150hrs 00z GFS



O_O

Yes ,very close to our shores,here in Puerto Rico, according to GFS.
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2803. Drakoen
Member Since: October 28, 2006 Posts: 57 Comments: 31660
2802. Drakoen
New Orleans hit on the GFS 00z
Member Since: October 28, 2006 Posts: 57 Comments: 31660
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i think 00Z run will show a direct hit on NOLA
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Quoting rareaire:
ok im out for the nite, you guys play nice. see ya tomorrow as the models forcast td2 to Tampa!


Thats not even right........good nite my friend.
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2797. KEEPEROFTHEGATE (Mod)
i out as well see ya all in the early am around 7
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2796. JRRP

162
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2795. JLPR
Quoting FLHurricaneChaser:
162.. laying the smackdown on Puerto Rico



Well that kinda takes away my tranquility =\
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ok im out for the nite, you guys play nice. see ya tomorrow as the models forcast td2 to Tampa!
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2793. KEEPEROFTHEGATE (Mod)


The Great Poofer

lol
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162.. laying the smackdown on Puerto Rico

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thanks everyone who gave an answer I appreciate it.
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2790. JLPR
150hrs 00z GFS



O_O
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Quoting hunkerdown:
that would reinforce its death


OUCH! (and LOL)
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Thank you too SCTonya
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Quoting willdunc79:
Ok again been off line since early this morning so how is 90L looking & doing tonight?


Not very organized.....Needs probably a day or 2 before becoming a TD or Storm.
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Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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