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 DM21Altestic:
My local news station meteorologist just said that "this African wave" will likely become a hurricane in the Gulf of Mexico in 7-10 days, so...
Who said that and where?
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Enough of the virus talk, there are many free downloads on the net to prevent your computer from being infected. I want to see what people are saying about the three systems that are being monitored.
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This time they actually updated


TD2

90L

AOI
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1982. jdjnola
Looks like the moisture 90L is throwing off to its west is starting to push away the dry air in front of the-artist-formerly-known-as-TD2. Tonight's dmax should be interesting...
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1981. amd
Quoting BiloxiIsle:

What "if" he is right??????


then me in Houston would be preparing for a hurricane strike, again.

But, almost all the models and quite a few of the long term forecasts forecasts a substantial trough to be entering the eastern part of the US at that time, so if that verifies, the gulf is closed for business.

Furthermore, it is highly irresponsible to state that a major hurricane will be in the gulf in 7 to 10 days considering that the odds of that forecast on average is small (trough or no trough)
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Quoting DM21Altestic:
Or even simpler: just don't click on the ads.

No click needed for a banner ad to run a script.
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1979. KEEPEROFTHEGATE (Mod)
barometer bob show live at 800pm edt

Link
Member Since: July 15, 2006 Posts: 165 Comments: 52276
Quoting frostynugs:
to anyone with virus issues... first of all, get rid of internet explorer if you are using it to browse the web. use firefox (www.firefox.com) and ad block plus (it's a plugin you can download for it, google it) as drak mentioned. Avira antivir (free-av.com) and malwarebyte's anti-malware are 2 free programs that will keep you virus free as long as you update them and scan with them regularly. I have not had a virus give me trouble in almost 2 years as a result.
I have firefox and I scan with AVG free and no problems either. Daily scan and no problems at all.
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Quoting amd:


that weatherman must be desperate for ratings.

What "if" he is right??????
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Quoting DM21Altestic:
Weather456, consider the source. It's Inaccuweather/Bastardi that made that.


yeah, but I may not agree with his ideas and forecasts but I respect him as a fellow met.
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Quoting JRRP:
just looking at this makes me think of a se fla event. Thoughts?
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So basically he took the 18Z
GFS at face value?? incredible -.-
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LOL JLPR....I thought it was only PR that didnt exist :P :P
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1972. amd
Quoting Drakoen:
All the benefits of being a Wunderground member for free. Get Firefox Ad Block Plus and you'll never see another Wunderground Ad!


noscript works just as well.
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1970. amd
Quoting DM21Altestic:

It's true. He even used his white marker/chalk device to point out his "plot"...taking it WNW through the Bahamas, Florida Straits and into the Central Gulf...


that weatherman must be desperate for ratings.
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Quoting JLPR:


lol we don't exist =P
never did.
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to anyone with virus issues... first of all, get rid of internet explorer if you are using it to browse the web. use firefox (www.firefox.com) and ad block plus (it's a plugin you can download for it, google it) as drak mentioned. Avira antivir (free-av.com) and malwarebyte's anti-malware are 2 free programs that will keep you virus free as long as you update them and scan with them regularly. I have not had a virus give me trouble in almost 2 years as a result.
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1967. JRRP
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Quoting FLGatorCaneNut:
Canesrule..... Great Block !!!!
huh?
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1964. Drakoen
All the benefits of being a Wunderground member for free. Get Firefox Ad Block Plus and you'll never see another Wunderground Ad!
Member Since: October 28, 2006 Posts: 57 Comments: 29714
Quoting Drakoen:



LOL!

0.o wow. Like a psychic if he's right he'll have fame for years .. If he's wrong .. well most won't notice ..
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I use a mac and i also have firefox ad block plus, never had a problem.
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1960. JLPR
Quoting Weather456:
no mention of the caribbean



lol we don't exist =P
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Canesrule..... Great Block !!!!
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Quoting TerraNova:


I'm running Malwarebytes' Antimalware which I've had a lot of success with.

Great for once your system is trying to load the junk...but why not avoid loading it to begin with?
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1955. Drakoen
Quoting DM21Altestic:
My local news station meteorologist just said that "this African wave" will likely become a hurricane in the Gulf of Mexico in 7-10 days, so...



LOL!
Member Since: October 28, 2006 Posts: 57 Comments: 29714
Quoting atmoaggie:

Running AdBlock Plus? Stops firefox from even loading the junk from the ad servers. Wunderful add-on: https://addons.mozilla.org/en-US/firefox/addon/1865


Yea, I use NoScript in Firefox and have had absolutely no problems, although according to my log it has blocked hundreds of malicious attacks over the last week or two.

Which have all come from google-serve ads, btw...
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LOL @ L.A. (Note my screen name...I'm in PCB) I've heard L.A. and Baja AL here.

Kind of got the chuckles over the 18z GFS....think I've seen THIS run a time or two in my tropics watchings over the years. Think it's time to cue up an old Cameo song....'Back and Forth'....hehehehe

Evenin' folks!
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no mention of the caribbean

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


I pay $5 a year for membership....I'm having no problems...haven't had a one.


Same.
Member Since: July 31, 2006 Posts: 56 Comments: 8112
Quoting atmoaggie:

Running AdBlock Plus? Stops firefox from even loading the junk from the ad servers. Wunderful add-on: https://addons.mozilla.org/en-US/firefox/addon/1865


I'm running Malwarebytes' Antimalware which I've had a lot of success with.
Member Since: July 30, 2007 Posts: 76 Comments: 4062
1948. Drakoen
Quoting TerraNova:
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.


Get firefox ad block plus
Member Since: October 28, 2006 Posts: 57 Comments: 29714
Quoting ALCoastGambler:
Your in Semms, right?

An area called chunchula Northwest of saraland.
Moved down here to attend USA for Met school.
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AL902009

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Quoting IKE:


I pay $5 a year for membership....I'm having no problems...haven't had a one.


same here
Member Since: July 24, 2005 Posts: 407 Comments: 19076
Our weather said: Changes in the tropics, not all bad news. TD2-no more. Tropical wave in Carribean could affect our weather this weekend.
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Quoting SouthALWX:
Actually if you're near the AL coast we're neighbors now. Recently moved to just north of mobile.
Your in Semms, right?
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Quoting TerraNova:
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.

Running AdBlock Plus? Stops firefox from even loading the junk from the ad servers. Wunderful add-on: https://addons.mozilla.org/en-US/firefox/addon/1865
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Quoting canesrule1:
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.
South Florida Stormwatch:Updated 8/13/09 @ 7:00 PM EDT

Quick Update today since little has changed from yesterdays update...

Do we stick a fork in TD2 now? Well, the NHC is still tracking it and nearly all the models continue to forecast that it will become a named storm. On the other hand, it was just downgraded to a remnant low and it looks pathetic on satellite right now so what is the call... I would like to monitor the area for a bit longer before passing final judgment. If it can hang on a few more days conditions for regeneration should improve, HWFR and NGP favor this scenario. CMC, GFS and GFDL drop this system over the next few days and from what I see now that seems more likely.
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1939. IKE
Quoting TerraNova:
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.


I pay $5 a year for membership....I'm having no problems...haven't had a one.
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1938. Drakoen
Seems Ana wishes to remain celibath from convection.
Member Since: October 28, 2006 Posts: 57 Comments: 29714
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.
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About JeffMasters

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