African tropical wave 99L has potential to develop

By: Dr. Jeff Masters , 3:10 PM GMT on July 30, 2012

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The first African tropical wave of 2012 with a potential to develop is Invest 99L, located in the Eastern Atlantic near 9°N 36°W, midway between the Lesser Antilles Islands and the coast of Africa. Visible satellite loops show a large area of the surrounding atmosphere has a pronounced counter-clockwise spin, though there is no surface circulation. The disturbance's heavy thunderstorm activity is pretty sparse, but appears to be slowly increasing. Water vapor satellite loops show that 99L has a reasonably moist environment, and the latest Saharan air layer analysis shows that the dry air from the Sahara lies well to the north of 99L. WInd shear over the disturbance is a light 5 - 10 knots, and ocean temperatures are 28°C, (82°F) which is well above the 26.5°C (80°F) threshold typically needed to allow formation of a tropical depression.


Figure 1. Morning satellite image of Invest 99L.

Forecast for 99L
Wind shear is expected to remain light for the next five days, and ocean temperatures will remain near 28°C, according to the 8 am EDT run of the SHIPS model. The disturbance is at 9°N, which is close enough to the Equator that the storm will have some difficultly getting spinning. Most of the models are showing some slow development of 99L, with the storm reaching the Lesser Antilles Islands on Saturday, August 3. NHC gave 99L a 20% chance of developing into a tropical depression by Wednesday morning. I expect the storm will have trouble with dry air at times this week as it crosses the Atlantic, but I give 99L a 50% chance of eventually developing into Tropical Storm Ernesto sometime in the next ten days. Residents and visitors to the Lesser Antilles Islands should anticipate heavy rains and strong winds from 99L beginning to affect the islands as early as Friday night. The long-range fate of 99L is uncertain, but a trough of low pressure is expected to be present over the Eastern U.S. early next week, which would be capable of turning 99L more to the northwest.

Hot in the Central U.S.
The heat in America's heartland continued on Sunday, with Wichita, KS hitting 111°F, just 3° short of their all-time hottest temperature of 114° set on 8/12/1936. Other notable highs on Sunday:

111° Coffeyville, KS
111° Winfield, KS
110° Chanute, KS
110° Parsons, KS
109° Joplin, MO (all-time record is 115° on July 14, 1954)

The low temperature in Tulsa, Oklahoma this Monday morning dropped to only 88°F. This is the all-time warmest low temperature in the city since record keeping began in 1905. The previous record warmest minimum temperature was 87°F set on August 2, 2011 and July 16, 1980. The high in Tulsa Monday - Wednesday is expected to reach 110° - 111°, close to the city's all-time hottest temperature of 115° set on August 10, 1936.

Jeff Masters

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1219. Patrap
Indeed, its causing havoc on a Global Scale.
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1218. 7544
looks like the antiles wave wants to go nnw instead west to the graveyard could it still surpise us and get a spin goin on
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Ya 7Hurricane 6TS!!! lol
Quoting Methurricanes:
Did I miss anything? gone since the 23rd
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1216. JRRP
blame climate change
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Quoting Civicane49:
Last image post:



I'm so glad we had this time together.....
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Did I miss anything? gone since the 21st
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Quoting TropicalAnalystwx13:

Where are you going? ;(


I have to go because I have a lot of work to do starting tomorrow. I will try to come back from time to time, if time permits.

Goodbye.
Member Since: July 21, 2011 Posts: 83 Comments: 7167
1212. pottery
Quoting washingtonian115:
Hey Pottery.Looks like it'll go north of you.

They generally do!
The joys of living at 11n.

(hope I have not crapped on my own front-step, there. LOL)
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Or we can blame El nino, la nina, MJO index, ONI, GW, Cape Verde, Azores high or maybe China, Chavez....

Anyhow, something is wrong....
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Quoting pottery:
First time on here today.
I see that you guys got bored enough to create some Mischief!

That's fine, you know.
But please, not so far south, eh ?
Hey Pottery.Looks like it'll go north of you.
Member Since: August 14, 2010 Posts: 10 Comments: 17151
Quoting Civicane49:
Once again, I would like to thank you all for letting me enjoy this site and visiting my blog updates. Remember, I will come back from time to time, if time permits. I will release my last very special entry of the year on September 11.

I am officially gone.

I will leave you with today’s blog entry on Invest 99L. Goodbye.

Where are you going? ;(
Member Since: July 6, 2010 Posts: 113 Comments: 32338
1208. hydrus
Quoting spathy:
To all the WUbians.
This is the stuff we are here for, Its good to see a spin and a model spark.
Let it play out with lots of conjecture,some beneficial rains and good times on the Blog :O)
Well put...It wont be long before we have a named system. I could make out a low center in the extreme N.E.Caribbean, but had trouble pulling the pic. So here is Saola.
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1207. pottery
First time on here today.
I see that you guys got bored enough to create some Mischief!

That's fine, you know.
But please, not so far south, eh ?
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Quoting GeorgiaStormz:


beryl already took that

And then Debby was our second.

Miami, I want whatever you got!
Member Since: July 6, 2010 Posts: 113 Comments: 32338
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The 00z tracks.

Member Since: April 29, 2009 Posts: 75 Comments: 14408
Once again, I would like to thank you all for letting me enjoy this site and visiting my blog updates. Remember, I will come back from time to time, if time permits. I will release my last very special entry of the year on September 11.

I am officially gone.

I will leave you with today’s blog entry on Invest 99L. Goodbye.
Member Since: July 21, 2011 Posts: 83 Comments: 7167
I don't know how accurate this is for an invest, but SHIPS has decent RI odds for 99L.

Prob of RI for 25 kt RI threshold= 39% is 3.1 times the sample mean(12.8%)
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Quoting BahaHurican:
Don't think we don't know ur beard is long enough to be indicators for the cardinal directions... all the patriarchs have long beards...


Now that's funny..I don't care who you are!
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1200. ncstorm
18z GFS Spread


228 hours


264 hours
Member Since: August 19, 2006 Posts: 13 Comments: 15744
1199. pottery
Quoting washingtonian115:
The ensembles show at least anywhere from a T.D to a strong tropical storm impacting the Lesser Antilles.Those folks need to pay attention.Hey where's Pottery?.

Present !
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Quoting MiamiHurricanes09:
99L appears like it could be the first real threat of the 2012 season.


beryl already took that
Member Since: February 11, 2012 Posts: 0 Comments: 9732
Quoting spathy:
To all the WUbians.
This is the stuff we are here for, Its good to see a spin and a model spark.
Let it play out with lots of conjecture,some beneficial rains and good times on the Blog :O)
Spathy is your nose really like that or just for computer sake?.Lol.
Member Since: August 14, 2010 Posts: 10 Comments: 17151
Quoting JLPR2:


Oh no, yes, an ULL to the north east could open a nice outflow channel for the system, helping it breathe.

Breathing is good.
Member Since: July 6, 2010 Posts: 113 Comments: 32338
Last image post:

Member Since: July 21, 2011 Posts: 83 Comments: 7167
Quoting MiamiHurricanes09:
99L appears like it could be the first real threat of the 2012 season.

So Debby wasnt enough to be a real threat? lol
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Geez... when u start to slobber on the keyboard, I think that's a sign u need to get off the computer...

So I think I'll go for a while... be back closer to midnight.

[snore]
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The ensembles show at least anywhere from a T.D to a strong tropical storm impacting the Lesser Antilles.Those folks need to pay attention.Hey where's Pottery?.
Member Since: August 14, 2010 Posts: 10 Comments: 17151
1191. Gearsts
Blame the sun!
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99L appears like it could be the first real threat of the 2012 season.
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Post #1182

Thank you, Sunlinepr.
Member Since: July 21, 2011 Posts: 83 Comments: 7167
1187. Grothar
Quoting Gearsts:
So that's means that they see it stronger as it aproches the islands?


That ULL would really have to move out of the way first, or it could really interfere with development. The divergence and convergence and not really that good yet, which is why it is slow to develop. I believe that is why there is again such a split with models like the CMC and the GFS. Right now, the GFS solution seems reasonable and movement through the Caribbean more likely. However, it will be moving in a more favorable environment and most likely will be a little stronger. When it reaches the end of the high, it could respond to the trough expected on the east coast toward the end of the week.
Member Since: July 17, 2009 Posts: 71 Comments: 26548
1186. Tygor
Well it's definitely not coming to Texas.
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Yes!!
Quoting washingtonian115:
These are the ensembles right?.
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Quoting SFLWeatherman:




These are the ensembles right?.
Member Since: August 14, 2010 Posts: 10 Comments: 17151
Quoting JLPR2:
What is this blasphemy? XD



I told you, HAARP.... Check the Arecibo RadioObservatory....

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Quoting Grothar:


I knew they would come around to my way of thinking. :)
It seemed pretty obvious to me that such a thing would happen... but like someone has said in this very blog... u gotta look at the current conditions, and also trends... models can only get you so far.
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Quoting Civicane49:

I wanted to tell everyone that I won’t be here in WU for a while starting tomorrow. I will also not be posting new entries for a long time, but I will release my last very special entry of the year on September 11. I have a lot of work to do starting on the beginning of August. I would like to thank you all for letting me enjoy this site and visiting my blog updates. It truly feels like a community here. However, I will come back on September 11 very briefly to let you guys know that I released a special entry. I will also come back from time to time, if time permits. I’ll miss this place.



Wish you the best.... Anyhow take your tablet with you and post from time to time....
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1179. JLPR2
What is this blasphemy? XD

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1178. Grothar
Quoting HurricaneDean07:

Comparison:
The consensus of the models yesterday:
Southern Leewards-Trinidad.
The Consensus of the models today:
Upper leeward islands.


I knew they would come around to my way of thinking. :)
Member Since: July 17, 2009 Posts: 71 Comments: 26548
Gonna eat. Be back in a bit.
Member Since: October 3, 2010 Posts: 40 Comments: 4129
Also looking at the Twave and waiting to see what happens when it gets S of Andros... I certainly expect this to bring a rainy beginning to August to at least part if not all of the Bahamas. Whether it does any more than that is anybody's guess.
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Now it going S FL!!
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Quoting GTcooliebai:
:( wish you all the best in your endeavors.


Thanks.
Member Since: July 21, 2011 Posts: 83 Comments: 7167
1172. JLPR2
Quoting Gearsts:
ULL cant help our system? I live in Aguadilla and im bored of sunshine everyday.


Oh no, yes, an ULL to the north east could open a nice outflow channel for the system, helping it breathe.
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Quoting Gearsts:
ULL cant help our system? I live in Aguadilla and im bored of sunshine everyday.


Here in Caguas the Relative humidity is high, its hot and I'm into taking my 5th shower of the day.... I was going to jump into the cistern, but it is empty....
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1170. 7544
imo where ever the wave by the antiles goes and its strenghth 99l should take that path but of course a bit stronger maybe a td after dmax tonight for 99l but the wave could also suprise us as i posted last ight and its still holding on hmmmmm but i think both will end up somewhere over or near south fl
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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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