Disturbance 90L close to tropical depression strength; TD 2 may rise again

By: Dr. Jeff Masters , 2:02 PM GMT on August 14, 2009

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A strong tropical wave (90L), with a large circulation and a moderate amount of heavy thunderstorm activity, is a few hundred miles southwest of the Cape Verdes Islands, off the coast of Africa. This morning's QuikSCAT pass shows that 90L has a large circulation, but this circulation is not yet well-formed, as it is elongated along an east-west axis. Satellite imagery from the European METEOSAT satellite show that the heavy thunderstorms associated with 90L are gradually becoming better organized, with some spiral banding evident on the south side of the storm. Satellite intensity estimates from NOAA already put 90L at tropical depression strength with 30 mph winds, but the storm does not yet have a well enough formed circulation to be classified as a depression. 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 was. However, there is some dry air from the SAL being sucked into the circulation of 90L, and this is retarding its development.

Wind shear is moderate, about 10 - 15 knots, but is forecast to fall to the low range, 5 - 10 knots, later today. Shear is then forecast to remain low for the next five days. Sea Surface Temperatures are about 28°C, and will remain in the 27 - 28°C range the next five days. The combination of low wind shear and sufficiently warm SSTs should allow 90L to develop into a tropical depression by Saturday, and potentially reach hurricane strength by Wednesday. Most of our reliable models strengthen 90L into a hurricane by Wednesday, when the storm is expected to be near the northern Lesser Antilles Islands. One important outlier is the ECMWF model, which has 90L passing to the north of the islands, and eventually recurving out to sea east of Bermuda. The ECMWF was by far the most reliable model for forecasting hurricane tracks last year. However, all of our models are pretty unreliable going out 5 days in advance for systems that have yet to reach tropical depression strength. Once 90L becomes a tropical depression and develops a well-formed circulation, the models will have a better handle on forecasting where it will go.


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

Tropical Depression Two may come back
Tropical Depression Two died yesterday, but may rise again. Satellite loops of the remnants of the storm show that heavy thunderstorms are again attempting a comeback near the axis of what is now a tropical wave. However, dry air continues to interfere with the development of the thunderstorm activity, and moderately high wind shear of 15 - 20 knots is also inhibiting the process. Wind shear over the remnants of TD 2 is expected to remain in the moderate range, 10 - 20 knots, over the next four days. Sea Surface Temperatures (SSTs) are 27°C, but will warm to 28°C two days from now. There is plenty of dry, stable air from the Saharan Air Layer (SAL) to the north and west that will continue to cause the storm problems. The relatively cool SSTs and dry air mean that any re-development of the storm will be slow to occur. NHC has given the system a medium (30 - 50% chance) of becoming a tropical depression again by Sunday morning. Only one reliable model, the NOGAPS, is predicting regeneration of TD 2. The NOAA Hurricane Hunters are flying research missions into the remnants of TD 2 today and Saturday.

I'll have an update Saturday morning, or earlier, if significant developments occur.

Jeff Masters

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Quoting cchsweatherman:


Just glad to know that you, StormW, Weather456, and I all perform our own analysis and we all stick by our own methods and approaches. You continue to do an amazing job.


Uh..so your saying everyone else doesn't? Buddy, I do the same, take last season for example. This season I've not been doing much forecasting and analyzing but I felt you may of left a few of us out.
Member Since: October 5, 2007 Posts: 3 Comments: 2151
Not much convection on the EAST side of the LLC with 90L - still some ways to go before a TD!!
Member Since: Posts: Comments:
Quoting ajcamsmom2:
please tell me that this can't happen...It is making me so very sick

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/carib/gfs/06/index_ten_s_loop.shtml


Anything can happen, given the right atmospheric conditions. But this is too far out to begin working yourself up needlessly. Keep watch, but do not panic. There is considerable uncertainty in the ultimate track of this system.
Member Since: Posts: Comments:
Quoting cg2916:

If you got a CD, why can't I? Cane likes you better than me, lol. Just kidding.
lol, hahaha
It has a LLC and has maintained constant convection for the past day i believe 02L is a TD right now just waiting on confirmation i would truely be surprised if it is not
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2255. Didnt show up on mine
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Quoting TampaSpin:


Canes you mean i can't give anyone a copy of that secret CD you made for me......OMGOSH!.....LMAO
ROFLMAO!!!!!!!!LMAO!!!!LOL, I can't stop laughing, HAHAHA!!!
2277. cg2916
Quoting TampaSpin:


Canes you mean i can't give anyone a copy of that secret CD you made for me......OMGOSH!.....LMAO

If you got a CD, why can't I? Cane likes you better than me, lol. Just kidding.
Member Since: Posts: Comments:
Quoting sammywammybamy:



Hey TampaSpin..

Ive been Out All Day
Please Fill Me In( NO Need for mean coments like Read Up!)

Has Td2 Re-Developed

And

Hows 90L

Again Please =/ ?


Don't know i just logged on also...looks like TD2 is nearly a Storm just looking at it an RECON appears to have confirmed nearly the same.
Member Since: September 2, 2007 Posts: 178 Comments: 20439
Good evening all! I'm in and out real quickly here. TD2 will possibly regenerate but only to die out again and 90L I believe will be the first named storm, hurricane and major hurricane of the season. Yes, I know pretty intense call but based on conditions out ahead and the area it will be within in 6-9 days I feel confident.
Member Since: October 5, 2007 Posts: 3 Comments: 2151
Quoting TampaSpin:


Thanks....I don't go with just what everyone else says...i do my own thing.....I respect StormW a ton and read his anaylsis very throughly. Sometimes i agree with him and some times in don't....but, i sure don't just cut and paste anyone elses analysis....again Thanks.


Just glad to know that you, StormW, Weather456, and I all perform our own analysis and we all stick by our own methods and approaches. You continue to do an amazing job.
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Quoting cg2916:

Yeah, but this is their welcome message:
******************************************************************
**WARNING**WARNING**WARNING**
This is a United States (Agency) computer system, which may be accessed
and used only for official Government business by authorized personnel.
Unauthorized access or use of this computer system may subject violators
to criminal, civil, and/or administrative action.
All information on this computer system may be intercepted, recorded,
read, copied, and disclosed by and to authorized personnel for official
purposes, including criminal investigations. Access or use of this
computer system by any person whether authorized or unauthorized,
constitutes consent to these terms.
**WARNING**WARNING**WARNING**
******************************************************************
**NOTICE**NOTICE**NOTICE**NOTICE**NOTICE**NOTICE**
This server is not considered operational. It is only supported
Monday thru Friday between 0700 and 1600 EST.
Report any problems to ncep.helpdesk@noaa.gov.
The NWS ftp server (tgftp.nws.noaa.gov) is the most reliable
source for operational data. That server is supported on a 24x7
basis. Please report any problems accessing that server to the
OOS Tech Control at toc.nwstg@noaa.gov or 301-713-0902.
**NOTICE**NOTICE**NOTICE**NOTICE**NOTICE**NOTICE**
*****************************************************************
ROFLMAO!
02L still listed as a LOW on the ATCF right now. Will keep watching for any changes.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Evening everybody.... been a year since I was on here.... the same guys on here still get me laughing!
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Quoting leftovers:
236 what do you think will happen in the gulf?
Well looks like were going to have something interesting going on with the surface trough interacting with the twave in the Bahamas. I'm thinking we could see something try to spin up.
Member Since: August 2, 2007 Posts: 19 Comments: 19234
please tell me that this can't happen...It is making me so very sick

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/carib/gfs/06/index_ten_s_loop.shtml
Member Since: Posts: Comments:
Quoting canesrule1:
sorry my bad, lol, and yes 02L has a 1006 pressure reading.I get it from a secret software which i can not reveal but u can get a lot of updates from here: Link


Canes you mean i can't give anyone a copy of that secret CD you made for me......OMGOSH!.....LMAO
Member Since: September 2, 2007 Posts: 178 Comments: 20439
TAFB holding at T1.5. Doubting that we'll see TD3 tonight at this point.
Member Since: August 2, 2007 Posts: 19 Comments: 19234

Actually this show winds strong enough to qualify as a TS IMO
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Click this: Non-Tasked Mission Data (for at least one product) which is above green leters, then click:08/14 Td2 NOAA N49RF UZNT13 -

and btw im not kidding on the software, it is a software that a meteorologist from the NHC gave me, and i can't tell u.
Quoting F5Tornado:
Hey guys tell Cyclone OZ that I had a computer malfuncton


Head back to the chat room. I'm pretty handy with computers...I can probably help you out of what happened...
Member Since: August 26, 2006 Posts: 10 Comments: 3617
Hey guys tell Cyclone OZ that I had a computer malfuncton
Member Since: Posts: Comments:
92L could be developing.
Quoting Weather456:
Is it me or does the solid area of convection west of the center a trademark?

Dean has the same structure as 90L and so did pre Georges 1998


92L could be developing.
Member Since: Posts: Comments:
2259. jipmg
Quoting Weather456:
Is it me or does the solid area of convection west of the center a trademark?

Dean has the same structure as 90L and so did pre Georges 1998



thats an old image
Quoting Weather456:
Is it me or does the solid area of convection west of the center a trademark?

Dean has the same structure as 90L and so did pre Georges 1998



Interesting Weather456, I'll be praying for you about this storm, looks to be headed straight to the Islands.
Member Since: July 1, 2008 Posts: 13 Comments: 7340
Quoting leftovers:
oh oh i can hear someone knocking on your door hope you are having a great night 236 just got back from a funeral my wifes friend 13 yr old girl killed herself hanging this is way funner than that was. tragic we keep thinking if she would of done this or that confused


I'm sorry to hear about that. And yes I'm having a good evening :)
Member Since: August 2, 2007 Posts: 19 Comments: 19234
Quoting stormpetrol:

Your analysis of ex TD2 from this morning so far has been spot on.


Thanks....I don't go with just what everyone else says...i do my own thing.....I respect StormW a ton and read his anaylsis very throughly. Sometimes i agree with him and some times in don't....but, i sure don't just cut and paste anyone elses analysis....again Thanks.
Member Since: September 2, 2007 Posts: 178 Comments: 20439
2255. cg2916
Quoting extreme236:


It even says in the README that you can send questions to them and stuff...doubt they would have to put that there for officials. Looks public to me.

Yeah, but this is their welcome message:
******************************************************************
**WARNING**WARNING**WARNING**
This is a United States (Agency) computer system, which may be accessed
and used only for official Government business by authorized personnel.
Unauthorized access or use of this computer system may subject violators
to criminal, civil, and/or administrative action.
All information on this computer system may be intercepted, recorded,
read, copied, and disclosed by and to authorized personnel for official
purposes, including criminal investigations. Access or use of this
computer system by any person whether authorized or unauthorized,
constitutes consent to these terms.
**WARNING**WARNING**WARNING**
******************************************************************
**NOTICE**NOTICE**NOTICE**NOTICE**NOTICE**NOTICE**
This server is not considered operational. It is only supported
Monday thru Friday between 0700 and 1600 EST.
Report any problems to ncep.helpdesk@noaa.gov.
The NWS ftp server (tgftp.nws.noaa.gov) is the most reliable
source for operational data. That server is supported on a 24x7
basis. Please report any problems accessing that server to the
OOS Tech Control at toc.nwstg@noaa.gov or 301-713-0902.
**NOTICE**NOTICE**NOTICE**NOTICE**NOTICE**NOTICE**
*****************************************************************
Member Since: Posts: Comments:
Quoting F5Tornado:
Hey CycloneOZ

I had a computer error, thats the last tiem I try to download something!


A computer error? When last I heard, you were going to install a Windows Media player (6.4?) What happened?
Member Since: August 26, 2006 Posts: 10 Comments: 3617
2253. mkmand
Quoting jipmg:
interesting developments tonight! How exciting

Agreed. Very exciting. I love this time of the year. And yes I am a weather geek!
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Quoting canesrule1:
sorry my bad, lol, and yes 02L has a 1006 pressure reading.I get it from a secret software which i can not reveal but u can get a lot of updates from here: Link

lol where on the page then
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Ameister12:

Can you tell me where exactly do you see a 90L LLC - need coordinates! I am seeing it around 11.5N - 30W or so... please confirm!! thx
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2249. Skyepony (Mod)
Fresh Quikscat of TD2~ Couple of 25kt vectors

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2248. 7544
Quoting louisianaboy444:
I gotta admit Tampaspin you called it


always on target so far good work tampa spin im a fan lol
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Is it me or does the solid area of convection west of the center a trademark?

Dean has the same structure as 90L and so did pre Georges 1998

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


here are a bunch of people who live in the antilles do not all speak 2 languages ... they also need information ..
sorry.
Quoting cg2916:

ROFLMAO!
ROFLMAO!!!!!!!!
2243. java162
Quoting Tropicaldan:


Greetings Dominica

90L is one to monitor for sure

Dan


definitly... althought the recent model track have it going back and forth north and below us, anything could happen. its a wait and see game
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Hey CycloneOZ

I had a computer error, thats the last tiem I try to download something!
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Quoting canesrule1:
por favor tu puede hablar engles?


here are a bunch of people who live in the antilles do not all speak 2 languages ... they also need information ..
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I gotta admit Tampaspin you called it
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Quoting extreme236:


Where does it say this at? I do not see that. Again, it would not be on a website available to the public if it were illegal.

Not illegal, but if we were to paste in images into the blog or everyone tried to access it, the max number of ftp connections get exceeded and people that need to get after that server have trouble doing so.
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Quoting extreme236:
Whats NOAA gonna do? Come to my house and arrest me for using their information on a weather blog that has been used for years? If they cared they would lock it with a password like RAMSDIS does.
ROFLMAO! good one.
2237. cg2916
Quoting CaneWarning:


The weather police are going to show up at your house and rain on you.

ROFLMAO!
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I'm seeing a better low level circulation in 90L.
Link
Member Since: August 9, 2009 Posts: 10 Comments: 4898
2235. 7544
hmm area n of cuba has been ganing alot of convection this hour

good dmav coming up tonight will tell us the story with all these systems get ready to see some xtra action then
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2234. jipmg
interesting developments tonight! How exciting

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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.