Dr. Jeff Masters' WunderBlog

TD 2 nearly dead; African disturbance 90L gathering strength
Posted by: Dr. Jeff Masters, 2:38 PM GMT en Agosto 13, 2009 +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
Categories: Hurricane
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2051. TexasHurricane 12:02 AM GMT en Agosto 14, 2009    
Quoting StormW:


Hello Mishy!


Hi,

Can you fill us in on the GOM?? Any thing of interest coming up or a no go?
Member Since: Julio 2, 2009 Posts: 0 Comments: 2811
2052. Drakoen 12:00 AM GMT en Agosto 14, 2009    
HWRF 18Z:
Member Since: Octubre 28, 2006 Posts: 57 Comments: 29012
2053. Drakoen 12:01 AM GMT en Agosto 14, 2009    
HWRF takes it to 935mb with 144knt winds at 900hpa
Member Since: Octubre 28, 2006 Posts: 57 Comments: 29012
2054. jipmg 12:01 AM GMT en Agosto 14, 2009    
I suspect based on the latest satellite images 90L is seemingly gaining some convective activity near the center.. also the models are somewhat more consistent this time around.. but still very far off from being anywhere near accurate in my honest opinion. Lets hope for the best, but a very interesting system to track
2055. Twinkster 12:02 AM GMT en Agosto 14, 2009    
Barometer Bob is starting please join us in storm chat at irc.hurricanehollow.org

we will be discussing 90L former TD 2 and the 5th Aniversary of HUrricane charley come join us
Member Since: Junio 7, 2007 Posts: 4 Comments: 932
2057. JRRP 12:02 AM GMT en Agosto 14, 2009    
Quoting weathersp:
HWRF 18z

it shows the center 14n
Member Since: Agosto 16, 2007 Posts: 0 Comments: 4358
2058. TampaMishy 12:03 AM GMT en Agosto 14, 2009    
Quoting StormW:


Hello Mishy!
Hey! So what is your prediction?
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2059. atmoaggie 12:03 AM GMT en Agosto 14, 2009    
Oh, I know, QBO = Quasi Beer Offering when being offered non-alcoholic brew.
Member Since: Agosto 16, 2007 Posts: 6 Comments: 12461
2060. Patrap 12:04 AM GMT en Agosto 14, 2009    
Member Since: Julio 3, 2005 Posts: 377 Comments: 113014
2062. Drakoen 12:04 AM GMT en Agosto 14, 2009    
The faster the system is the better chance it has at hitting the SE U.S.
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2063. TampaMishy 12:04 AM GMT en Agosto 14, 2009    
Quoting DM21Altestic:
So what category do you guys think this system will eventually end up peaking as?

I say Category Four.
Two
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2064. STORMMASTERG 12:04 AM GMT en Agosto 14, 2009    
Barometer bob show is on.
2066. jlp09550 12:05 AM GMT en Agosto 14, 2009    
I'm guessing we'll have to get our hurricane evacuation plans ready next week. :x
Member Since: Febrero 21, 2008 Posts: 1 Comments: 340
2068. HurricaneJoe 12:06 AM GMT en Agosto 14, 2009    
Quoting DM21Altestic:
So what category do you guys think this system will eventually end up peaking as?

I say Category Four.


If it gets under the right conditions, Cat 5 isn't out of the question.
2069. Twinkster 12:06 AM GMT en Agosto 14, 2009    
Barometer Bob is starting please join us in storm chat at irc.hurricanehollow.org

we will be discussing 90L former TD 2 and the 5th Aniversary of HUrricane charley come join us

STORMW will be on the show. come join us
Member Since: Junio 7, 2007 Posts: 4 Comments: 932
2070. Drakoen 12:06 AM GMT en Agosto 14, 2009    
Quoting DM21Altestic:

And the slower the system goes, the better chance it has of taking a dive?


Yes.
Member Since: Octubre 28, 2006 Posts: 57 Comments: 29012
2071. kingzfan104 12:07 AM GMT en Agosto 14, 2009    
2074. hurricane23 12:09 AM GMT en Agosto 14, 2009    
Quoting Drakoen:
The faster the system is the better chance it has at hitting the SE U.S.


That would be correct.
Member Since: Mayo 14, 2006 Posts: 8 Comments: 13331
2076. kingzfan104 12:10 AM GMT en Agosto 14, 2009    
2077. TexasHurricane 12:10 AM GMT en Agosto 14, 2009    
Man, I am just such an impatient person...I just want to know , is my area going to be affected by a tropical storm or hurricane? It can't be that hard to answer can it? :)

I know, I know - Wait and Watch!!
Member Since: Julio 2, 2009 Posts: 0 Comments: 2811
2078. Skyepony (Mod) 12:10 AM GMT en Agosto 14, 2009    
90L
Member Since: Agosto 10, 2005 Posts: 145 Comments: 29993
2080. Drakoen 12:13 AM GMT en Agosto 14, 2009    
Quoting DM21Altestic:
When I get my myspace friend Drak to join, there'll be two Drak's, lol.

No offense, Drak, you're the better meteorogist easily...it will just be funny.


Also, if 90L speeds up a lot in the next 120 hours, is there still some hope that it will be a fish/Bermuda storm?


Drak or Drakoen is not even my real name.
Member Since: Octubre 28, 2006 Posts: 57 Comments: 29012
2081. TexasHurricane 12:11 AM GMT en Agosto 14, 2009    
Quoting StormW:


If you're speaking of 90L, only thing I can say right now, if what I was just looking at in the steering layers forecast, it won't be a fish anytime soon. In fact, I prefer the 18Z GFDL track.


which is?
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2082. FloridaTigers 12:11 AM GMT en Agosto 14, 2009    
I've been gone for the last few hours. 90L sped up? Or slowed down?
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2083. dcoaster 12:12 AM GMT en Agosto 14, 2009    
From what I'm seeing on CIMSS, 90L doesn't look like it has everything together yet...
2085. stormwatcherCI 12:13 AM GMT en Agosto 14, 2009    
Quoting DM21Altestic:
165 mph is too bullish for an African wave, right Drak?
Hurricane Dean in 2007 was a classic Cape Verde storm originating on Aug 11. Peak winds at 145kts(approx 165 mph)
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2086. Drakoen 12:13 AM GMT en Agosto 14, 2009    
GFDL:
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2087. ALCoastGambler 12:14 AM GMT en Agosto 14, 2009    
StormW I like the runs myself. Yesterday it was heading for Mobile Bay. Now PCB, Fl. Maybe next further East, and so on. We know these models always change from run to run. So everyone from TX to ME need to watch for the time being
2088. HurricaneJoe 12:14 AM GMT en Agosto 14, 2009    
Give it time, it just recently came off of the coast.
2090. Orcasystems 12:15 AM GMT en Agosto 14, 2009    
Member Since: Octubre 1, 2007 Posts: 77 Comments: 26110
2091. PORTCHARLOTTE72 12:15 AM GMT en Agosto 14, 2009    
Quoting DM21Altestic:
So what category do you guys think this system will eventually end up peaking as?

I say Category Four.
Quoting DM21Altestic:
So what category do you guys think this system will eventually end up peaking as?

I say Category Four.
lol there will be no trpical development in the atlantic this season 0-0-0
2092. SWFLDigTek 12:17 AM GMT en Agosto 14, 2009    
I'm out, take care...
Member Since: Agosto 31, 2008 Posts: 117 Comments: 398
2093. aquak9 12:17 AM GMT en Agosto 14, 2009    
Quoting Drakoen:


Drak or Drakoen is not even my real name.


No Way!!!
Member Since: Agosto 13, 2005 Posts: 163 Comments: 25036
2094. stormhank 12:17 AM GMT en Agosto 14, 2009    
Hi everyone...does anyone have a good link for eastern atlantic satellite ? thanks so much..
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2095. Drakoen 12:18 AM GMT en Agosto 14, 2009    
Quoting aquak9:


No Way!!!


Who would name their child Drak
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2096. HurricaneJoe 12:18 AM GMT en Agosto 14, 2009    
Quoting stormhank:
Hi everyone...does anyone have a good link for eastern atlantic satellite ? thanks so much..


Link
2097. sarasotaman 12:18 AM GMT en Agosto 14, 2009    
StormW is on the Barometer Bob Show right now!!
2098. Drakoen 12:19 AM GMT en Agosto 14, 2009    
The GFDL and HWRF look to be just as fast as the GFS only further north. Definitely bears watching.
Member Since: Octubre 28, 2006 Posts: 57 Comments: 29012
2099. PcolaDan 12:20 AM GMT en Agosto 14, 2009    
Quoting Drakoen:


Who would name their child Drak

A Count from Romamia?
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2100. aquak9 12:19 AM GMT en Agosto 14, 2009    
drakoen..I think we all knew that Drakoen was not your real name....
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2101. stormwatcherCI 12:21 AM GMT en Agosto 14, 2009    
Quoting PcolaDan:

A Count from Romamia?
LOL
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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.

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