TD 2 nearly dead; African disturbance 90L gathering strength

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

Share this Blog
4
+

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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 2237 - 2187

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72Blog Index

2237. jdjnola
The-artist-formerly-known-as-TD2 is the "low pressure remnant" (per the NHC) that just won't die.
Member Since: Posts: Comments:
Congrats on your promotion to captain aqauk9. LOL!

Quoting KerryInNOLA:
Never said that captain. Have dropped the we because the "big boys" felt threatened. They apparently feel if your not in crowd your not entitled to give opinion, they call it downcasting. If only they could practise what they preach. Even thought there are 3 of us (read last PM post) we are now I.
Member Since: Posts: Comments:
Quoting BILOXISAINT2:
i am, and who are you?
I am the mail lady bro what's up!!
Member Since: Posts: Comments:
Quoting squirrel61:
I hope this will not be interpreted as an attack or bickering, but I feel I will make few friends with this commment...
Jeff, I realize that this is yours and others livelihood, and you love your jobs, but I find it a bit disconcerting when these storms are anthropomorphized on the site, and it seems as if there is genuine disappointment when disturbances do not turn into tropical storms or hurricanes...we should marvel at nature, but like Frankenstein and his monster, realize we cannot forget the potential ramifications of anything coming to fruition in our enthusiasm for what we do and live for.
I turn to your site for straight up and accurate info since I live in a hurricane hotspot...


I have never seen Dr. Masters seem disappointed when something didn't form. Some on his blog may be like that but he doesn't control what they post.
Member Since: Posts: Comments:

Slow, slow, quick-quick slow, Foxtrot, anyone?
:-)

If either TD2 or 90L make it to me [@12-61.7], that'd only be a TS, right? The lower, the weaker?
Real question: What are my chances of another Ivan, or Emily, compared to, say, PR or Barbados?
Member Since: Posts: Comments:
2232. jdjnola
Quoting conchygirl:
ok, what shall we call it?


I'll get banned if I say it...
Member Since: Posts: Comments:
2231. gator23
Quoting HurricaneLovr75:
What up all.

What are the chances of invest 90 being a Cat 5 at landfall if it reaches the GOM? Asking cuz the GOM is so warm.

No one can answer this. not even god.
Member Since: Posts: Comments:
Just looked at the long rage GFS for 90L.... Cat 3 (or higher) hitting FL? ...... Let's see how much things change....
Member Since: Posts: Comments:
i am, and who are you?
Member Since: Posts: Comments:
2228. gator23
Quoting KerryInNOLA:
Never said that captain. Have dropped the we because the "big boys" felt threatened. They apparently feel if your not in crowd your not entitled to give opinion, they call it downcasting. If only they could practise what they preach. Even thought there are 3 of us (read last PM post) we are now I.

I think people were just taken at back by what you said because you seemed so sure when in reality you cant be.
Member Since: Posts: Comments:
The facts dont lie. TD2..Ana..wrong.. The blob over Africa.. Bill... Wrong..Just let the pros do their job and comment on that!
Member Since: Posts: Comments:
Guys just ignore KerryinNOLA. Don't quote him.
Member Since: August 10, 2009 Posts: 3 Comments: 672
I hope this will not be interpreted as an attack or bickering, but I feel I will make few friends with this commment...
Jeff, I realize that this is yours and others livelihood, and you love your jobs, but I find it a bit disconcerting when these storms are anthropomorphized on the site, and it seems as if there is genuine disappointment when disturbances do not turn into tropical storms or hurricanes...we should marvel at nature, but like Frankenstein and his monster, realize we cannot forget the potential ramifications of anything coming to fruition in our enthusiasm for what we do and live for.
I turn to your site for straight up and accurate info since I live in a hurricane hotspot...
Member Since: Posts: Comments:
TD2 is also running into 10-15kt shear and decreasing as it moves north of dew west
Member Since: June 13, 2009 Posts: 2 Comments: 11215
Quoting Skyepony:


Model preformance tends to vary per storm, season, etc. Here's all the model errors for TD2 over time. 90L hasn't been around long enough to compare model preformance.
and what is the best model as far as ind intensity? is it ships?
Member Since: Posts: Comments:
Quoting BILOXISAINT2:
Clueless
hey Biloxi Saint you wouldn't happen to be the cableman would ya?
Member Since: Posts: Comments:
What up all.

What are the chances of invest 90 being a Cat 5 at landfall if it reaches the GOM? Asking cuz the GOM is so warm.
Member Since: Posts: Comments:
Quoting KEEPEROFTHEGATE:
yes but no as they slow they slow fast and can back track
But I was told correctly. Thought so Just checking. So as long as it doesn't slow it's harder to turn, or slow to quickly, or backtrack. Ok think I got it. Thanks, Alan
Member Since: Posts: Comments:
2218. Skyepony (Mod)
Quoting kingzfan104:
which are the better ones to look at, the ensemble models or the regular computer models here? please help guys. i know most of you had me on ignore, but please help me. that was me last year, i am no longer looking to be a nuisance, please take me off ignore, i have serious questions.


Model preformance tends to vary per storm, season, etc. Here's all the model errors for TD2 over time. 90L hasn't been around long enough to compare model preformance.
Member Since: Posts: Comments:
2217. gator23
Quoting BILOXISAINT2:
Clueless


All this where will it go is moot. Long range forecasts mean nothing

This is from Max Mayfields blog yesterday:

"In my opinion, there is a very good reason that the NHC only issues forecasts out to five days. At this time, the science doesn’t support an official forecast beyond that time period. However, the Internet has made it easy for anyone to view the longer range forecasts. No one can tell you with any certainty how accurate they will be."
Member Since: Posts: Comments:
2216. gator23
Quoting pcolasky:
I live in the northern gulf coast, and the local TV stations are reporting that the wave over the islands is going to come this way. Therefore, we have a 60% chance of rain for Sun, Mon, and Tues. Any thoughts from the wise predictors out there?

That seems accurate but development is not forecast
Member Since: Posts: Comments:
Quoting weatherblog:
One things for sure, this is not a Gulf storm. A trough will eventually bring this north, where is the question.

These are my percentages for a CONUS hit for 90L-

Recurve- 30%
Florida east coast- 35%
The rest of the east coast- 30%
Dissipate- 4%
GOM- 1%

We also need to watch TD 2 as regeneration is possible, and it could possibly threaten Florida as models are suggesting.
Clueless
Member Since: Posts: Comments:
extreme, where do those models take the storm?
Member Since: Posts: Comments:
I live in the northern gulf coast, and the local TV stations are reporting that the wave over the islands is going to come this way. Therefore, we have a 60% chance of rain for Sun, Mon, and Tues. Any thoughts from the wise predictors out there?
Member Since: Posts: Comments:
Quoting wunderkidcayman:

I think we need to watch ex-TD2 as well but knowing how weak it is I think it will likely to be a caribbean system

thats what im seeing too
Member Since: Posts: Comments:
2211. KEEPEROFTHEGATE (Mod)
Quoting ALCoastGambler:
KOTG, Got a question. I know you the right one, so I will trust your answer....lol
Was always told, higher foward speed storms are harder to "recurve". Right or Wrong?
yes but no as they slow they slow fast and can back track
Member Since: July 15, 2006 Posts: 169 Comments: 53296
HWRF and GFDL both make 90L a powerful hurricane on their 18Z run.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Quoting pcolasky:


Bottle it!
ok, what shall we call it?
Member Since: Posts: Comments:
Quoting atmoaggie:

NOLA tap water kills swine flu virus?...useful info!


well, most municipal water supplies do have trace amounts of pharms in them...mostly hormones and statins (cholesterol drugs)...and caffeine...'course you'd have to drink a few 1000 gallons to get a dose
Member Since: Posts: Comments:
Quoting conchygirl:
Now that is funny!lol


Bottle it!
Member Since: Posts: Comments:
Quoting weatherblog:


I think SE Florida is probable but really it could anywhere on the coast. If it were to hit Florida it is most likely it would recurve up the state like Frances and Jeanne and not make it in the GOM. But, as far as the CONUS goes, I'm more worried about Florida since that would be the first place to be hit and there'll be more than enough time to worry about another landfall.

how strong do you think it would be then? thank you so much for answering me. im just kinda jittery because wilma hurt us bad and it was only a cat 1 here in northern broward, a cat 3 or hell, with these model projects, even more, we could be in for a lot of trouble. again, thanks for the help
Member Since: Posts: Comments:
Quoting weatherblog:
One things for sure, this is not a Gulf storm. A trough will eventually bring this north, where is the question.

These are my percentages for a CONUS hit for 90L-

Recurve- 30%
Florida east coast- 35%
The rest of the east coast- 30%
Dissipate- 4%
GOM- 1%

We also need to watch TD 2 as regeneration is possible, and it could possibly threaten Florida as models are suggesting.

I think we need to watch ex-TD2 as well but knowing how weak it is I think it will likely to be a caribbean system
Member Since: June 13, 2009 Posts: 2 Comments: 11215
Quoting atmoaggie:

NOLA tap water kills swine flu virus?...useful info!
Now that is funny!lol
Member Since: Posts: Comments:
2202. jdjnola
Quoting atmoaggie:

NOLA tap water kills swine flu virus?...useful info!


Disclaimer: this does not constitute medical advice!
Member Since: Posts: Comments:
Quoting kingzfan104:
if you had to guess, and it hit the florida east coast, would that be se florida, and how strong do you think it would be if that happened


I think SE Florida is probable but really it could anywhere on the coast. If it were to hit Florida it is most likely it would recurve up the state like Frances and Jeanne and not make it in the GOM. But, as far as the CONUS goes, I'm more worried about Florida since that would be the first place to be hit and there'll be more than enough time to worry about another landfall.
Member Since: Posts: Comments:
which are the better ones to look at, the ensemble models or the regular computer models here? please help guys. i know most of you had me on ignore, but please help me. that was me last year, i am no longer looking to be a nuisance, please take me off ignore, i have serious questions.
Member Since: Posts: Comments:
Quoting atmoaggie:

NOLA tap water kills swine flu virus?...useful info!
LOL Have you ever drank that stuff....lol
Member Since: Posts: Comments:
Quoting antonio28:


If you live in NE caribbean stay tune PR and the island above 15N.


Scary :(
Member Since: Posts: Comments:
Quoting jdjnola:


I have empty water jugs in my living room to fill up with (ew New Orleans) tap water in case of a hurricane or swine flu.

NOLA tap water kills swine flu virus?...useful info!
Member Since: Posts: Comments:
I know this weekend I will go over my evacuation plans and storm prep plans and I'm on the west coast of Florida. If this thing goes across the state, I could still see some flooding and high winds. Even if it stays out to sea I still think its a good idea for everyone, no matter where you live, to brush up on your plans.
Member Since: Posts: Comments:
Quoting weatherblog:
One things for sure, this is not a Gulf storm. A trough will eventually bring this north, where is the question.

These are my percentages for a CONUS hit for 90L-

Recurve- 30%
Florida east coast- 35%
The rest of the east coast- 30%
Dissipate- 4%
GOM- 1%

We also need to watch TD 2 as regeneration is possible, and it could possibly threaten Florida as models are suggesting.
if you had to guess, and it hit the florida east coast, would that be se florida, and how strong do you think it would be if that happened
Member Since: Posts: Comments:
There sure are a lot of purple lines pointing towards the Carribean, Puerto Rico and SE Fl through the keys on the ensemble models. Thank God we are days and days away and as we know that'll all change..... I hope
Member Since: Posts: Comments:
The GFS indicates a major for DC and NY?


Is that right?Wow.
Member Since: Posts: Comments:
Quoting CaribBoy:
Compared to 12z runs, 18z HWRF and GFDL look slightly south and closer to the northernmost islands. right?


If you live in NE caribbean stay tune PR and the island above 15N.
Member Since: Posts: Comments:
2191. jdjnola
Quoting louisianaboy444:
Baromter Bob and StormW are on and talking about 90L... Saying that somewhere in the U.S. in the next 10 days Hurricane Watches will probably be issued....

This weekend folks.... everyone should brush up and get those supplies, check those shutters IF this comes your way


How do i tune into that?


I have empty water jugs in my living room to fill up with (ew New Orleans) tap water in case of a hurricane or swine flu.
Member Since: Posts: Comments:
If I had to pick a model to be correct, I think the GFDL is most accurate right now.
Member Since: Posts: Comments:
One things for sure, this is not a Gulf storm. A trough will eventually bring this north, where is the question.

These are my percentages for a CONUS hit for 90L-

Recurve- 30%
Florida east coast- 35%
The rest of the east coast- 30%
Dissipate- 4%
GOM- 1%

We also need to watch TD 2 as regeneration is possible, and it could possibly threaten Florida as models are suggesting.
Member Since: Posts: Comments:
am i the only one getting a feeling that this thing will continue trending south into the caribbean?
Member Since: Posts: Comments:
2187. Walshy
This is interesting. Look at this loop from weather-underground.

Did Tropical Storm Guillermo have a eye earlier? Or were the clouds just rotating fast?

Link
Member Since: Posts: Comments:

Viewing: 2237 - 2187

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | 72Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.