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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1087. TeJoe
Quoting sctonya:
Keeper, do you have the link to the google map that zoomiami was working on? TIA



Here's the Link but it's old. http://orcasystems.ca/debbie.htm
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got a question for teh experts on here...(and you all know who you are). everyone is saying fish...i just looked at all the maps on teh FSU site and so far there is no sign of curvature....any ideas why everyone is saying fish other than crossed fingers???
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With showers and thunderstorms moving through the Jacksonville area, the remains of Capt. Scott Speicher arrived at NAS Jacksonville this afternoon. I won't bother posting the link but you can follow on any Jax news station. Burial will be tomorrow. God bless him for his service to this country as well as all who have and continue to do so!!
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Hey guys the curve all u people keep talking about was stated on the news as "highly unlikely" so i wouldn't be saying that SFLA is out of the picture.
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Quoting popartpete:
Great map StormMaster G...is that not the same moniker used for TWC's Dr. Greg Forbes?? He doesn't fit the title, in my opinion...that sounds like a gansta rap artist, which he is not.
Thanks,those are 2 paths shown right now.
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1081. cg2916
Quoting TampaSpin:
TD2 is trying really hard to make a comeback....don't know if it will make it but, storms are starting to fire near the COC!

Those storms seem to be getting sheared away, though.
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Quoting hurricanejunky:
TD2 looks like it's trying to actually wrap convection around the COC. The wave near the Bahamas is sure flaring up a LOT of convection as well.


Maybe it's a good thing to get some strong storms over the area north of Puerto Rico into the Bahamas.

No sunshine, plus some slight cooling from rain could take a degree out of the SSTs here for when either TD2 or 90L possibly pass through!!!

Of course there is still several days in between for the sun to come back out...but every little bit helps.
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1079. java162
it appears that come next week one paradise island willl be downgraded.(according to the models)
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Quoting Funkadelic:
The faster 90L forms, the better. A stronger system will likely re-curve after the lesser antiles.

A weeker system will churn west/WNW and can perhaps affect the CONUS. Overall it's a Lose-Lose situation for the islands it appears. (Based on models)


So it seems to be more on the developing slower side right? Which moves it more west?
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I guess I'll let know my parents about that wave getting close to Puerto Rico. Worth watching...
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TD2 is still trying to get its act together again, but you can clearly see a zone of dry air extending right into the storm's low level on center on water vapor (Link)
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Quoting popartpete:
Thanks...I was unaware of there being two.


Location error for me: it's actually in the NE Caribbean. My bad.
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Quoting STORMMASTERG:
This is my path
Great map StormMaster G...is that not the same moniker used for TWC's Dr. Greg Forbes?? He doesn't fit the title, in my opinion...that sounds like a gansta rap artist, which he is not.
Member Since: July 10, 2007 Posts: 0 Comments: 429
Well guess we are back in business. Not even this year without summer will stop storm formation.
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TD2 is trying really hard to make a comeback....don't know if it will make it but, storms are starting to fire near the COC!
It might be likeing the warmer waters it is entering.
Member Since: September 2, 2007 Posts: 178 Comments: 20443
Good Afternoon Everyone...from South Fla..
There is a blob that seems to be spooling up around the Turks / Cacaos Islands. Any suggestions on what site can be used to provide a satellite shot of the amount of convection within?
Thanks...Stay well...
Steve
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1070. Thaale
Quoting OSUWXGUY:


In general, the quicker 90L organizes with only a moderately strong ridge to its north, the more latitude it would gain. A slower organizing system, based on lower level steering currents would gain less latitude and would be more a threat to the Lesser Antilles in 5 days...
Thanks; appreciate the help!
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jasoniscoolman10 + 1050 = ignore.

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1067. sctonya
Keeper, do you have the link to the google map that zoomiami was working on? TIA

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1066. Prgal
About post 1050: Jason, I am VERY interested in this system because it has a chance of impacting my island directly. Apparently you only care about what can affect YOU and discard want wont. Please have more respect for others. Thank you.
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Quoting caneswatch:


There's also another box located around NE Cuba. There's 2 boxes.
Thanks...I was unaware of there being two.
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TD2 looks like it's trying to actually wrap convection around the COC. The wave near the Bahamas is sure flaring up a LOT of convection as well.
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Quoting CaneWarning:


I thought the same thing.
me too
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@1050
What

the

heck?!?


You need to calm down, Jason. REALLY!
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Quoting KEHCharleston:
And you had been doing so well.


I thought the same thing.
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Usually people are more concerned about if it's going to hit them, yeah. Which is understandable especially considering what some people have been.

I wish for recurvature, if it a 'cane can. Of course, on the flip side, that will often mean it comes towards me instead. Usually these are extratropical but still strong. More than once ex-hurricanes come over here and cause considerable damage. It's also theoretically possible for a direct hit. Faith for example, tracked towards here whilst still tropical. Debbie only went extratropical mere miles away. And so on.

But, perhaps a holistic point of view or because the chances of a hit are so low anyway, I'd rather they recurve even if they do come up here than hit someone hundreds of miles away, but stronger.

That's just my point, though.
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1058. fire635
And... Goodbye...to jasoniscoolman
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This is my path
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Quoting jasoniscoolman10:
09L IS 3,000 MILES WAYS FOR THE USA U PEOLPE .........
And you had been doing so well.
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I was looking at my local news, and they had one of those updates and they stated "We cold have another tropical depression in the next hours, stay tuned!"
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Wait...I have another common quote that we see often, "Let's see what such-and-such will do during Di-Max..."
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1053. KEEPEROFTHEGATE (Mod)
250

WHXX01 KWBC 131826

CHGHUR

TROPICAL CYCLONE GUIDANCE MESSAGE

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL

1826 UTC THU AUG 13 2009



DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.

PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE

AND SUBTROPICAL CYCLONE INFORMATION.



ATLANTIC OBJECTIVE AIDS FOR



TROPICAL CYCLONE TWO (AL022009) 20090813 1800 UTC



...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...

090813 1800 090814 0600 090814 1800 090815 0600



LAT LON LAT LON LAT LON LAT LON

BAMS 14.2N 37.9W 14.5N 39.9W 15.0N 41.9W 15.3N 44.4W

BAMD 14.2N 37.9W 14.9N 40.4W 15.7N 43.0W 16.7N 45.7W

BAMM 14.2N 37.9W 14.5N 39.9W 15.0N 42.1W 15.5N 44.6W

LBAR 14.2N 37.9W 14.4N 39.8W 15.0N 42.2W 15.7N 44.9W

SHIP 25KTS 23KTS 24KTS 27KTS

DSHP 25KTS 23KTS 24KTS 27KTS



...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...

090815 1800 090816 1800 090817 1800 090818 1800



LAT LON LAT LON LAT LON LAT LON

BAMS 16.3N 48.0W 19.4N 57.3W 23.0N 65.8W 26.9N 70.6W

BAMD 17.9N 48.6W 20.6N 53.9W 22.7N 58.5W 22.6N 62.1W

BAMM 16.3N 47.8W 18.1N 55.7W 20.8N 64.0W 23.8N 69.4W

LBAR 16.4N 48.1W 18.3N 55.0W 20.3N 62.1W .0N .0W

SHIP 29KTS 33KTS 35KTS 36KTS

DSHP 29KTS 33KTS 35KTS 36KTS



...INITIAL CONDITIONS...

LATCUR = 14.2N LONCUR = 37.9W DIRCUR = 275DEG SPDCUR = 7KT

LATM12 = 14.0N LONM12 = 36.4W DIRM12 = 267DEG SPDM12 = 8KT

LATM24 = 14.3N LONM24 = 34.4W

WNDCUR = 25KT RMAXWD = 40NM WNDM12 = 30KT

CENPRS = 1008MB OUTPRS = 1012MB OUTRAD = 150NM SDEPTH = M

RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM



$$

NNNN
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Quoting RyanFSU:Just another HWRF plug for 12z, as the storm is ramped up to Category 5 strength in 5 days. BRAlso, more GFS images here at my FSU website:

Thanks Ryan for Stopping In!

Like your website for the Hi-Res model output and your work with ACE Climatology. Keep up the excellent work!
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Actually interestingly enough I now work for FPL. So if a storm threatens, I have to stay in town. We go immediately into storm mode as soon as a storm passes.
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1049. KEEPEROFTHEGATE (Mod)
049

WHXX01 KWBC 131901

CHGHUR

TROPICAL CYCLONE GUIDANCE MESSAGE

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL

1901 UTC THU AUG 13 2009



DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.

PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE

AND SUBTROPICAL CYCLONE INFORMATION.



ATLANTIC OBJECTIVE AIDS FOR



DISTURBANCE INVEST (AL902009) 20090813 1800 UTC



...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...

090813 1800 090814 0600 090814 1800 090815 0600



LAT LON LAT LON LAT LON LAT LON

BAMS 11.7N 23.3W 12.5N 26.1W 13.0N 29.7W 13.1N 33.5W

BAMD 11.7N 23.3W 12.0N 25.9W 12.0N 28.7W 11.8N 31.5W

BAMM 11.7N 23.3W 12.1N 25.9W 12.5N 29.0W 12.6N 32.2W

LBAR 11.7N 23.3W 11.9N 25.5W 12.2N 28.5W 12.5N 31.7W

SHIP 25KTS 29KTS 37KTS 48KTS

DSHP 25KTS 29KTS 37KTS 48KTS



...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...

090815 1800 090816 1800 090817 1800 090818 1800



LAT LON LAT LON LAT LON LAT LON

BAMS 12.9N 38.0W 12.1N 46.9W 10.8N 54.5W 9.5N 60.1W

BAMD 11.9N 34.5W 12.4N 41.1W 13.2N 47.3W 14.4N 52.8W

BAMM 12.7N 35.9W 12.4N 43.7W 11.5N 49.5W 12.5N 52.5W

LBAR 12.7N 35.6W 13.2N 44.1W 13.2N 48.0W .0N .0W

SHIP 60KTS 79KTS 89KTS 98KTS

DSHP 60KTS 79KTS 89KTS 98KTS



...INITIAL CONDITIONS...

LATCUR = 11.7N LONCUR = 23.3W DIRCUR = 280DEG SPDCUR = 7KT

LATM12 = 11.5N LONM12 = 21.9W DIRM12 = 278DEG SPDM12 = 7KT

LATM24 = 11.2N LONM24 = 20.3W

WNDCUR = 25KT RMAXWD = 60NM WNDM12 = 25KT

CENPRS = 1009MB OUTPRS = 1012MB OUTRAD = 180NM SDEPTH = M

RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM



$$

NNNN
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Thanks
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Quoting Vortex95:


As Drak said Convection is not good, it is going to need to rebound or it will be Sunday rather than Friday.


'rebound' is saying 90L is pathetic looking. Which it is not.
90L's getting better organized by the minute. Will likely blow up tonight and get TD status.
I think a better term you are looking for is more along the lines of 'more organization' which it does in order to become a TD.
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Wondering about evacuation shelters in other states. I have been told be someone who is assigned to a shelter, that, though some shelters will not be used in case of a mandatory evacuations - others will. In other words, if a full evacuation of Charleston County were to be called, evacuation centers will still be opened in the mandatory area. Those who are required to man the shelters, have no choice - they are to man the shelters regardless of the mandatory warning.

One other interesting piece of information. On local websites (city, media etc), the shelters are listed as Red Cross shelters. Actually, during the storm, it is workers from the Department of Social Services that man the shelters. After the storm, the Red Cross takes over.

What do you do in your state?

I am off to work, so I will check back later tonight.
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Quoting Thaale:
If 90L is developing more quickly than some of the models had forecast, once that development is fed into later model runs would they be likely to trend further north?


In general, the quicker 90L organizes with only a moderately strong ridge to its north, the more latitude it would gain. A slower organizing system, based on lower level steering currents would gain less latitude and would be more a threat to the Lesser Antilles in 5 days...
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1044. cg2916
Sorry, misread the info.
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1043. sctonya
could someone post the link to the google earth project that zoomiami was working on at one time. I had it in my old computer, but forgot to save it to this one....TIA!!
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1041. KEEPEROFTHEGATE (Mod)
Quoting canesrule1:
Very unimpressive satellite presentation might cost her being TD status by Friday.

should'nt see anything impressive with convection till the start of dmax around 11 pm tonight edt wax on tonight during day tomorrow then wane a little then wax up again it dev in cycles and its a big cirulation so it may be longer till dev occurs
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Yes, it would be .2 which is only a slight wobble, as it has been doing.

It's at 14N dead on. Certainly wasn't at 12N 6 hours ago.
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1039. RyanFSU
Just another HWRF plug for 12z, as the storm is ramped up to Category 5 strength in 5 days.





Also, more GFS images here at my FSU website: Link
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Quoting BiloxiGirl:
What are the chances we could have a GOM Coast event at any point next week? There is so much to watch I can't keep up with it just checking in here and there.
From what I understand, the yellow circle in the Caribbean has the best shot to enter the GOM at the present time. I cannot predict the future of TD 2 or the red circle area. I'd have to get my crystal ball out, and THEN I can say for sure. lol!
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Quoting cg2916:
TD2 has gained 2 degrees north in six hours. I got this from the ATCF database. It's bginning to recurve.


recurve???

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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.