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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Quoting wxchaser97:
This wouldn't be good.


Please dont let TWC see that..the way they hyped Irene last year they would have a field day with that run warning all Northerners to evacuate
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Quoting 954FtLCane:

Florida is a big state depends on what part you're talking about. I wouldn't mind a nice rain soaking tropical stor here in SE Fla.
N/C FL
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Quoting Slamguitar:
This blog has been pretty bored all July if we're already talking about landfall locations for 99L.



Bored is good for those of us on the gulf coast :D


As for the invest I am going to air on the conservative side with the GFS run. Only issues I have with it at this point are intensity (of course), and timing, I think its a bit slow in movement as it stands at its current run, but I think that will change in the next few runs as it gets a better handle on the system. After all some models still have not picked up the system at all (ngps).

@120 hrs gfs Link


As far as visible sats, maybe up to 30% by 8 but I doubt it. Will be looking to see if it gets anymore deep convection going by tomorrow.



Keep in mind the later it develops (to a certain point) the more threat it could pose to the U.S. due to the trough scenario currently in the cards for next week. Only a slight turn NW from the end of the GFS run fcast point would take you up the corridor and into a more NNW-NW steering current.



Will wait and see but its nothing to worry about in the near term certainly, but it does draw my eye.
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Man I just hope this storm isn't in Florida by the 10th... These trolls are making me worried.
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Quoting wxchaser97:
FL has had enough with tropical systems this year.

Florida is a big state depends on what part you're talking about. I wouldn't mind a nice rain soaking tropical stor here in SE Fla.
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Quoting LargoFl:
..yes the storms sure knocked out our drought,its gone
I remember everyone saying north FL is so dry and then these 2 storms took care of that.
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well only 20%,so far nothing to get worked up over,its a longgggg way off and so many things can happen,but..its something we can watch and try to gauge direction and path,meanwhile here in the USA we have some current bad weather to watch out for huh
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Quoting Grothar:
Little heavier convection building. I think within 48 hours we could have a depression or even stronger.


Yo Gro how are ya?.They may up the chances soon.
Member Since: August 14, 2010 Posts: 10 Comments: 15716
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Quoting washingtonian115:
I think his space bar isn't working.But he does have a point.Back in 04 Frances and Jeanne made landfall in almost the same exact location just three weeks apart.In 2005 the northern Gulf coast go hit by several times with storm tracks being only a few miles to 100 miles apart with Rita being the the more western track.


well he has a lot of points., between his words lol

that being said I do agree with the idea that sometimes storms can follow similar paths
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This blog has been pretty bored all July if we're already talking about landfall locations for 99L.
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Personally I don't see this going to the carolinas IMO!
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Quoting wxchaser97:
I'm not living anywhere near FL and I know that N/C FL has had sooooo much rain from Beryl & Debby.
..yes the storms sure knocked out our drought,its gone
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Quoting galvestonhurricane:


We shouldn't worry about landfall locations until 99L actually develops. Good afternoon everyone!


Agree with you on that one.
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Little heavier convection building. I think within 48 hours we could have a depression or even stronger.


Member Since: July 17, 2009 Posts: 63 Comments: 23727
Quoting Hurricanes101:


what.is.up.with.all.the.dots.between.your.words.?
I think his space bar isn't working.But he does have a point.Back in 04 Frances and Jeanne made landfall in almost the same exact location just three weeks apart.In 2005 the northern Gulf coast go hit by several times with storm tracks being only a few miles to 100 miles apart with Rita being the the more western track.
Member Since: August 14, 2010 Posts: 10 Comments: 15716
I for one will get interested once a surface
circulation develops. Where this happens
will determine alot. Until then its fun
to make bold predictions ...with so many,
someone will end up being right, anyway...
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Quoting Chiggy:
There is a reason why the GFS and EURO aren't too excited on 99L - so talking about the possible end scenarios at this point... dare I say it.., pointless!


so in other words we are wasting our time? Many on this blog love to bounce around ideas and talk about possibilities. You saying it is pointless basically insults many of us here. Yea thanks lol

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Quoting MAweatherboy1:
Any particular reason JTWC brought Saola's intensity down from 65kts to 55kts?

I really don't know, Saola looks to be strengthening.
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Quoting TropicalAnalystwx13:

Either North Carolina or South Carolina.

Lucky you.
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Quoting MAweatherboy1:
Any particular reason JTWC brought Saola's intensity down from 65kts to 55kts?



true eye or just a hole?
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Quoting LargoFl:
I surely agree with that
I'm not living anywhere near FL and I know that N/C FL has had sooooo much rain from Beryl & Debby.
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There is a reason why the GFS and EURO aren't too excited on 99L - so talking about the possible end scenarios at this point... dare I say it.., pointless!
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Quoting TropicalAnalystwx13:

Either North Carolina or South Carolina.
Hopefully not as bad as last year(Irene).
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ANOTHER UPPER
LEVEL LOW IS CENTERED OVER THE STRAITS OF FLORIDA NEAR 23N81W.
EXPECT...A COLD FRONT TO MOVE OVER GEORGIA AND N FLORIDA IN 24
HOURS. ADDITIONAL PREFRONTAL CONVECTION WILL REACH THE NE GULF.
ALSO EXPECT RAIN AND SHOWERS TO PERSIST OVER THE BAY OF
CAMPECHE.
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Quoting MAweatherboy1:
Any particular reason JTWC brought Saola's intensity down from 65kts to 55kts?



I'm not sure.
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Quoting wxchaser97:
FL has had enough with tropical systems this year.
I surely agree with that
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Quoting MAweatherboy1:
Any particular reason JTWC brought Saola's intensity down from 65kts to 55kts?


No idea.
Member Since: July 6, 2010 Posts: 109 Comments: 30268
Quoting islander101010:
get.hit.once.expect.to.get.it.again


what.is.up.with.all.the.dots.between.your.words.?
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Any particular reason JTWC brought Saola's intensity down from 65kts to 55kts?

Member Since: February 11, 2012 Posts: 79 Comments: 7297
Quoting wxchaser97:

I was thinking 30% at 2pm but since they didn't then 30% at 8pm sounds good. Where do you think a landfall would be if it takes the US path?

Either North Carolina or South Carolina.
Member Since: July 6, 2010 Posts: 109 Comments: 30268
get.hit.once.expect.to.get.it.again
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BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOBILE AL
304 PM CDT MON JUL 30 2012

THE NATIONAL WEATHER SERVICE IN MOBILE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
SOUTH CENTRAL ESCAMBIA COUNTY IN NORTHWEST FLORIDA...
SOUTHEASTERN BALDWIN COUNTY IN SOUTHWEST ALABAMA...

* UNTIL 400 PM CDT

* AT 254 PM CDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING
WINDS OVER 60 MPH WAS LOCATED 10 MILES WEST OF BELLVIEW...OR 4
MILES NORTHWEST OF LILLIAN...AND MOVING SOUTH AT 15 MPH.

* LOCATIONS IMPACTED INCLUDE...
PERDIDO BEACH... ORANGE BEACH... WARRINGTON...
MYRTLE GROVE... BELLVIEW... SUMMERDALE...
LILLIAN... FOLEY... ELBERTA...

THIS INCLUDES INTERSTATE 10 IN FLORIDA BETWEEN MILE MARKERS 1 AND 5.

LAT...LON 3048 8773 3049 8773 3059 8736 3046 8731
3046 8730 3044 8730 3035 8725 3033 8726
3032 8724 3029 8755 3027 8755 3024 8767
TIME...MOT...LOC 2004Z 018DEG 13KT 3042 8750
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Quoting LargoFl:
..and dont forget recent Debby,her flooding was terrible
FL has had enough with tropical systems this year.
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534. CJ5
Quoting CaicosRetiredSailor:

BLAME HUMANS FOR ARCTIC SEA ICE LOSS

Analysis by Kieran Mulvaney 
Mon Jul 30, 2012 10:00 AM ET 

At least 70 percent, and as much as 95 percent, of sea ice loss in the Arctic is the result of human activities such as the burning of greenhouse gases, according to a new study.


It does not help either side to distort the research. I am not blaming you. Every single news story I have heard framed the headline the same way. The study did not determine the melt was due to man. It determined it was not contributed to the AMO.


From the researcher himself: "We could only attribute as much as 30% [of the Arctic ice loss] to the AMO," he said. "Which implies that the rest is due to something else, and this is most likely going to be man-made global change."
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Quoting MAweatherboy1:
We may see 30% at 8PM:


I was thinking 30% at 2pm but since they didn't then 30% at 8pm sounds good.
Quoting TropicalAnalystwx13:
Here's how I would put it...

Stays in Caribbean (ECMWF/Operational GFS): 30%
Out to sea: 20%
Clips NE Caribbean and heads towards USA: 50%

Just educated guesses based on the pattern and latest model runs.
Where do you think a landfall would be if it takes the US path?
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Quoting TropicalAnalystwx13:
Here's how I would put it...

Stays in Caribbean (ECMWF/Operational GFS): 30%
Out to sea: 20%
Clips NE Caribbean and heads towards USA: 50%

Just educated guesses based on the pattern and latest model runs.

I would go with that....but at the moment doesnt look that much different than it did this morning...
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rainy.season.for.latin.america.
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Quoting wxchaser97:

I like Jacksonville, been there a few times. They already got Beryl so hopefully that members solution doesnt happen.
..and dont forget recent Debby,her flooding was terrible
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Here's how I would put it...

Stays in Caribbean (ECMWF/Operational GFS): 30%
Out to sea: 20%
Clips NE Caribbean and heads towards USA: 50%

Just educated guesses based on the pattern and latest model runs.
Member Since: July 6, 2010 Posts: 109 Comments: 30268
We may see 30% at 8PM:

Member Since: February 11, 2012 Posts: 79 Comments: 7297
Quoting MAweatherboy1:
One more, this member is thinking NE Florida:


I like Jacksonville, been there a few times. They already got Beryl so hopefully that members solution doesnt happen.
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Quoting aislinnpaps:


Looks like it, but I'm only here until this weekend, visiting my son, then I head back home to Louisiana, Rita/Ike/Gustav country. But I'm on a ten year hiatus from hurricanes and have a few years left on that. *S*
Hope you have safe travels back home sweetie.I am close to Gulf Shores Ala.Just moved here from Mobile about a month ago.I have a question.Doent a high pressure steer a storm away and a low pressure draws them? I was just wondering.TIA
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Invest 99L:

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Quoting galvestonhurricane:


We shouldn't worry about landfall locations 99L actually develops...
Right, it may go through the Caribbean and die there but this is one model that shows a Long Island landfall.
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What's up with all the unwanted forecasts being presented by the models?
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One more, this member is thinking NE Florida:

Member Since: February 11, 2012 Posts: 79 Comments: 7297

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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.