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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LOL and alot of people were calling it Ana right before this morn's 5am advis.

Ana is gonna be 90L by the way it looks
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1335. cg2916
It's dead.
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1334. KEEPEROFTHEGATE (Mod)
Quoting hurricane23:
Convection is still some what on the scattered side BUT overall organization has improved.Should be a TD during the next 1-2 days.

View of both systems...

tonight 23 she will have her feet wet and first 24 over water outta the way with more than likly the first convective cycle startin after 11 pm tonight edt and be in its first waning cycle by this time tomorrow evening
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FORECAST POSITIONS AND MAX WINDS

INITIAL 13/2100Z 14.2N 38.3W 25 KT...REMNANT LOW
12HR VT 14/0600Z 14.3N 39.7W 25 KT...REMNANT LOW
24HR VT 14/1800Z 14.5N 42.2W 25 KT...REMNANT LOW
36HR VT 15/0600Z 14.8N 44.8W 25 KT...REMNANT LOW
48HR VT 15/1800Z 15.1N 47.7W 25 KT...REMNANT LOW
72HR VT 16/1800Z 16.5N 54.0W 25 KT...REMNANT LOW
96HR VT 17/1800Z 19.0N 61.0W 25 KT...REMNANT LOW
120HR VT 18/1800Z 23.0N 67.5W 25 KT...REMNANT LOW

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1332. HadesGodWyvern (Mod)
Japan Meteorological Agency

Tropical Disturbance Summary (1800z 13AUG)
=========================================
At 3:00 AM JST, Tropical Depression, Former Etau (1000 hPa) located at 36.0N 152.0E has 10 minute sustained winds of 25 knots with gusts of 40 knots. The depression is reported as moving north at 10 knots

--
and here is what is left of Etau
Member Since: May 24, 2006 Posts: 52 Comments: 46910
1331. Drakoen
Quoting weatherboykris:


I'm basing my opinion on their track record with TD2 right after it left the African coast. If I remember correctly, they were fairly bullish.


Different system different conditions.
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1329. IKE
TROPICAL DEPRESSION TWO DISCUSSION NUMBER 11
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022009
500 PM AST THU AUG 13 2009

WHILE PERSISTING OVER THE PAST SEVERAL HOURS...THE AREA OF
CONVECTION JUST WEST OF THE CENTER OF TROPICAL DEPRESSION TWO IS
TOO SMALL TO BE CLASSIFIED USING THE DVORAK TECHNIQUE. INDEED...IT
HAS BEEN ALMOST 24 HR SINCE ENOUGH ORGANIZED CONVECTION EXISTED TO
GET A DATA-T NUMBER. BASED ON THIS...THE DEPRESSION HAS DECAYED
INTO A REMNANT LOW PRESSURE AREA. IT IS LIKELY THAT THE SYSTEM
WILL CONTINUE TO PRODUCE BURSTS OF CONVECTION FOR THE NEXT SEVERAL
DAYS...AND A FASTER FORWARD MOTION IS EXPECTED BY THE END OF THE
FORECAST PERIOD. THIS IS THE BASIS FOR KEEPING A 25 KT INTENSITY
FOR THE REMNANTS THROUGH 120 HR. SEVERAL OF THE INTENSITY FORECAST
MODELS CONTINUE TO FORECAST STRENGTHENING...SO IF THE SYSTEM FINDS
A MORE FAVORABLE ENVIRONMENT IT COULD REGENERATE.

THE INITIAL MOTION IS 275/8. THERE IS LITTLE CHANGE TO THE
FORECAST PHILOSOPHY FROM THE PREVIOUS FORECAST. THE SYSTEM IS
ON THE SOUTH SIDE OF A LOW/MID-LEVEL RIDGE...WHICH SHOULD RESULT IN
A WESTWARD MOTION FOR THE NEXT COUPLE OF DAYS. AFTER THAT...IT
SHOULD GRADUALLY TURN WEST-NORTHWESTWARD TOWARD A WEAKNESS IN THE
RIDGE OVER THE WESTERN ATLANTIC. THE NEW FORECAST TRACK IS
BASICALLY AN UPDATE OF THE PREVIOUS ADVISORY. IT SHOULD BE NOTED
THAT SEVERAL GLOBAL MODELS SHOW THE REMNANT LOW WEAKENING TO A
TROPICAL WAVE...AND IF THIS OCCURS THE SYSTEM COULD MOVE FARTHER
SOUTH THAN CURRENTLY FORECAST.

FORECAST POSITIONS AND MAX WINDS

INITIAL 13/2100Z 14.2N 38.3W 25 KT...REMNANT LOW
12HR VT 14/0600Z 14.3N 39.7W 25 KT...REMNANT LOW
24HR VT 14/1800Z 14.5N 42.2W 25 KT...REMNANT LOW
36HR VT 15/0600Z 14.8N 44.8W 25 KT...REMNANT LOW
48HR VT 15/1800Z 15.1N 47.7W 25 KT...REMNANT LOW
72HR VT 16/1800Z 16.5N 54.0W 25 KT...REMNANT LOW
96HR VT 17/1800Z 19.0N 61.0W 25 KT...REMNANT LOW
120HR VT 18/1800Z 23.0N 67.5W 25 KT...REMNANT LOW

$$
FORECASTER BEVEN
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TD-2 is dead.
Member Since: August 10, 2009 Posts: 3 Comments: 672
3189. RadarRich 2:48 PM GMT on August 13, 2009
apology for repost, new to this posting,,,just got lost in the transition to new blog

Just an observation and something that may need to be monitored a little more closely. Watching quite a few satelite images and loops for the last few hours. AOI just to the east of the SE Bahamas is showing more signs of circulation and much more convection quickly.
Probably a mid level entity at present, but it bears watching since it is close to any significant populated land mass. The area aprox. 21-23 north & 68-69 west moving WNW

From Key West afternoon discussion....

"A TROPICAL WAVE...CURRENTLY LOCATED ALONG
68W SOUTH OF 21N...WILL BE MOVING INTO THE FLORIDA STRAITS FRIDAY
NIGHT.

Thank godness conditions do not warrant tropical formation at present or this little system has Katrina-Like memories, when she was just off the Bahamas.

BTW, I do believe dyslexia is a common problem in our society, and for some reason it wants to rear its ugly head in the WU blog. So when you see those many typos from a lot of "we know who" bloggers, it is actually not from being dumb/stupid, but just an affliction that is tough to overcome.....
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Stephanie Abrams is the most annoying person on the weather channel. Even Al and Mike Bettis try to cover up thier attitude towards her. You can see it written on thier faces.
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RIP TD2. (Not saying it won't reform.)
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Quoting Drakoen:


I don't see how we can tell how strong the system will be that far out given the favorable conditions.


I'm basing my opinion on their track record with TD2 right after it left the African coast. If I remember correctly, they were fairly bullish.
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WTNT32 KNHC 132041
TCPAT2
BULLETIN
TROPICAL DEPRESSION TWO ADVISORY NUMBER 11
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022009
500 PM AST THU AUG 13 2009

...DEPRESSION HAS DECAYED INTO A REMNANT LOW PRESSURE AREA...

AT 500 PM AST...2100 UTC...THE CENTER OF THE REMNANTS OF TROPICAL
DEPRESSION TWO WAS LOCATED NEAR LATITUDE 14.2 NORTH...LONGITUDE
38.3 WEST OR ABOUT 930 MILES...1500 KM...WEST OF THE SOUTHERNMOST
CAPE VERDE ISLANDS.

THE LOW IS MOVING TOWARD THE WEST NEAR 8 MPH...13 KM/HR. THE
REMNANTS OF THE DEPRESSION ARE EXPECTED TO CONTINUE A GENERAL
WESTWARD MOTION FOR THE NEXT COUPLE OF DAYS.

MAXIMUM SUSTAINED WINDS ARE NEAR 30 MPH...45 KM/HR...WITH HIGHER
GUSTS. THE REMNANTS ARE EXPECTED TO CHANGE LITTLE IN STRENGTH OVER
THE NEXT COUPLE OF DAYS.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB...29.77 INCHES.

...SUMMARY OF 500 PM AST INFORMATION...
LOCATION...14.2N 38.3W
MAXIMUM SUSTAINED WINDS...30 MPH
PRESENT MOVEMENT...WEST OR 275 DEGREES AT 8 MPH
MINIMUM CENTRAL PRESSURE...1008 MB

THIS IS THE LAST PUBLIC ADVISORY ISSUED BY THE NATIONAL HURRICANE
CENTER ON THIS SYSTEM. THE SYSTEM WILL BE CLOSELY MONITORED FOR
SIGNS OF REGENERATION. ADDITIONAL INFORMATION ON THIS SYSTEM CAN BE
FOUND IN HIGH SEAS FORECASTS ISSUED BY THE NATIONAL WEATHER
SERVICE...UNDER AWIPS HEADER NFDHSFAT1 AND WMO HEADER FZNT01 KWBC.

$$
FORECASTER BEVEN
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1321. HadesGodWyvern (Mod)
yup 10 minute sustained wind average is lower wind speed than 1 minute
Member Since: May 24, 2006 Posts: 52 Comments: 46910
Quoting weatherboykris:


Can I ask why some people seem to have this obsession with the GOM since 2005? That's a serious question, not tryin to be rude...


The Gulf is as warm as it was in 2005 lol. Some people just cant help themselves.
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Quoting weatherboykris:


Can I ask why some people seem to have this obsession with the GOM since 2005? That's a serious question, not tryin to be rude...


Probably because if it gets into the gulf its almost 100% likely to hit land. Also, the gulf has been hit hard so I think some are paranoid.
Member Since: April 26, 2009 Posts: 3 Comments: 3667
BULLETIN
TROPICAL DEPRESSION TWO ADVISORY NUMBER 11
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022009
500 PM AST THU AUG 13 2009

...DEPRESSION HAS DECAYED INTO A REMNANT LOW PRESSURE AREA...

AT 500 PM AST...2100 UTC...THE CENTER OF THE REMNANTS OF TROPICAL
DEPRESSION TWO WAS LOCATED NEAR LATITUDE 14.2 NORTH...LONGITUDE
38.3 WEST OR ABOUT 930 MILES...1500 KM...WEST OF THE SOUTHERNMOST
CAPE VERDE ISLANDS.

THE LOW IS MOVING TOWARD THE WEST NEAR 8 MPH...13 KM/HR. THE
REMNANTS OF THE DEPRESSION ARE EXPECTED TO CONTINUE A GENERAL
WESTWARD MOTION FOR THE NEXT COUPLE OF DAYS.

MAXIMUM SUSTAINED WINDS ARE NEAR 30 MPH...45 KM/HR...WITH HIGHER
GUSTS. THE REMNANTS ARE EXPECTED TO CHANGE LITTLE IN STRENGTH OVER
THE NEXT COUPLE OF DAYS.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB...29.77 INCHES.

...SUMMARY OF 500 PM AST INFORMATION...
LOCATION...14.2N 38.3W
MAXIMUM SUSTAINED WINDS...30 MPH
PRESENT MOVEMENT...WEST OR 275 DEGREES AT 8 MPH
MINIMUM CENTRAL PRESSURE...1008 MB

THIS IS THE LAST PUBLIC ADVISORY ISSUED BY THE NATIONAL HURRICANE
CENTER ON THIS SYSTEM.
THE SYSTEM WILL BE CLOSELY MONITORED FOR
SIGNS OF REGENERATION. ADDITIONAL INFORMATION ON THIS SYSTEM CAN BE
FOUND IN HIGH SEAS FORECASTS ISSUED BY THE NATIONAL WEATHER
SERVICE...UNDER AWIPS HEADER NFDHSFAT1 AND WMO HEADER FZNT01 KWBC.

$$
FORECASTER BEVEN
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Quoting weatherfan92:


I wouldn't be surprised. My gut feeling is 90L is going through S. FL and into the Gulf.


Can I ask why some people seem to have this obsession with the GOM since 2005? That's a serious question, not tryin to be rude...
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1315. rxse7en
Quoting IKE:
IKE, any idea how much rain and wind Africa actually gets from the train of storms each year? Gorillas must be getting moldy by now.
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Quoting hurricane23:


Well that isn't nice.
Member Since: April 26, 2009 Posts: 3 Comments: 3667
Quoting TexasHurricane:
In all seriousness....

Who thinks we will be looking at some tropical trouble in the GOM soon?


I wouldn't be surprised. My gut feeling is 90L is going through S. FL and into the Gulf.
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Yeah, and is it too early to be talking pinhole eye lol. how do the latest intensity forecasts compare to historical storms in that area in the atlantic? 112mph seems pretty strong so close to Africa. That would put it at 400mph when it inevitably hits NOLA
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Also notice TD2 becomes a wave and goes to SOFL on that map...
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Member Since: May 14, 2006 Posts: 8 Comments: 13841
1308. java162
Quoting TexasHurricane:
In all seriousness....

Who thinks we will be looking at some tropical trouble in the GOM soon?


seriously? are you wishing for something?
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All too familiar.
TD10
Later formed into Katrina in the Bahamas.
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Quoting KEEPEROFTHEGATE:
farfromnormal

abby normal
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1305. Prgal
Statement as of 5:00 am AST on August 13, 2009


...Depression weakens...

At 500 am AST...0900 UTC...the center of Tropical Depression Two was
located near latitude 14.0 north...longitude 36.9 west or about 840
miles...1350 km...west of the southernmost Cape Verde Islands.


The depression is moving toward the west near 12 mph...19 km/hr...
and this general motion is expected for the next couple of days
with a gradual Bend to the west-northwest and an increase in
forward speed.


Maximum sustained winds are near 30 mph...45 km/hr...with higher
gusts. Little change in strength is forecast during the next 24
hours but the depression could still become a tropical storm in a
couple of days.


The estimated minimum central pressure is 1007 mb...29.74 inches.


...Summary of 500 am AST information...
location...14.0n 36.9w
maximum sustained winds...30 mph
present movement...west or 270 degrees at 12 mph
minimum central pressure...1007 mb


the next advisory will be issued by the National Hurricane Center at
1100 am AST.


$$
Forecaster Blake
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1304. Drakoen
Quoting weatherboykris:
Something that needs to be considered when looking at the more northerly 12z Euro or HWRF models for 90L, is that they are likely intensifying the storm a bit too quickly. It's larger, and that will slow it down. I'll be surprised if we have TD3 tonight. And yes, TCFA has been issued.


I don't see how we can tell how strong the system will be that far out given the favorable conditions.
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1282. StormFreakyisher 8:34 PM GMT on August 13, 2009
Quoting tallahasseecyclone:
The Weather Channel is the worst channel on television. I flip over to CSPAN when I get bored of the crap on there. They need to make a "it could happen tomorrow" about what the world would be like if their channel didn't stink so bad.

Please enough, I have had it with the weather channel.They changed so much they are trying to act like an entertainment show, they lost all the primary focus on weather itself and lack in detail of it such as hurricanes now.



true...but hey they do have "AL" in the mornings....lol...freakin NBC....that's the problem with TWC..
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Worth noting that the HPC, which coordinates with the NHC, has 90L at 20N 60W in 7 days.
http://www.hpc.ncep.noaa.gov/medr/day7nav.html
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hey can someone link me tothe tcfa
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Quoting CaneWarning:


Not looking good for our island friends.


Seriously it does not....HUM.....i could be a very large wind field and a Major Hur. by then also.....I expect this storm because of the amount of atmosphere it is turning to have one hell of a wind field from the center.
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Quoting TexasHurricane:
In all seriousness....

Who thinks we will be looking at some tropical trouble in the GOM soon?


I dont think it will be big but yes i think something is coming
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Something that needs to be considered when looking at the more northerly 12z Euro or HWRF models for 90L, is that they are likely intensifying the storm a bit too quickly. It's larger, and that will slow it down. I'll be surprised if we have TD3 tonight. And yes, TCFA has been issued.
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Highest all year.

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1296. java162
Quoting CaneWarning:


Not looking good for our island friends.

the models keep it on a weaterly track
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Quoting hurricane23:
Convection is still some what on the scattered side BUT overall organization has improved.Should be a TD during the next 1-2 days.

View of both systems...



Man that thing is HUGE!
Member Since: August 10, 2009 Posts: 3 Comments: 672
It looks like Guillermo has formed an eye.
Might become a hurricane soon.
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In all seriousness....

Who thinks we will be looking at some tropical trouble in the GOM soon?
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1292. Drakoen
Quoting clwstmchasr:
Those are some scary long range ensemble members and they show the range of possibilities

Drakeon,

I live here on the West Coast of Fl and because of the troughs, we have been under a west wind pattern the entire summer. Because of that, I see Fl being protected (as of today). Do you see tins long term summer pattern changing and maybe FL could be under the gun?


The east coast of Florida is under the microscope. I would look for GOM storms in September and October. I think that October will get an upward MJO phase which may prolong this El Nino year a little longer than typical El Nino years.
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1291. HadesGodWyvern (Mod)
Japan Meteorological Agency

Tropical Disturbance Summary 1800z 13AUG
==========================================
SUBJECT: Tropical Depression East-Northeast of Marshalls Island

At 3:00 AM JST, Tropical Depression, Former Maka (1008 hPa) located at 13.7N 178.4E has 10 minute sustained winds of 30 knots with gusts of 50 knots. The depression is reported as moving west-southwest at 10 knots
Member Since: May 24, 2006 Posts: 52 Comments: 46910
Quoting CaneWarning:


I miss John Hope. He was way better than anything TWC has now.
Jonn & I shared the same birthday...May 14th.
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ike..i hope there right and it's just a swell maker...but as hot as the GOM is right now...anything is still possible for sure...
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Drak are those the 12z ensems? Im on limited connectivity atm and cannot check for myself.
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1287. Patrap
Quoting tarpontexas:
Patrap...thanks for the video on hot towers. very informative



Always like to keep it real and informative,thanx(everyone)
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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.

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