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 19N81W:
this system has an awful lot to overcome...let alone get out of the itcz....that being said with the high in place and its already very low lattitude I doubt it making a turn sharp enough to miss the caribbean....it would have to start turning by tonight tomorrow...just dont see it. I think its coming in to the caribbean where it will likely die or just be a rainmaker...didnt the euro put it in the caribbean?


I wouldn't be surprised if it overcomes them, truth be told. We've had countless systems the last few years overcome way worse.
Member Since: July 8, 2005 Posts: 259 Comments: 24477
Quoting MississippiWx:
Here is a GIF loop I made of the global SST anomalies at the end of each month. Starts at January and goes up until today, July 30th. Interesting to watch the changes in anomalies throughout the globe the past 7 months.



why were the oceans so cold
especially the southern oceans
seems strange considering how warm the land was
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North every way
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Now Alabama pay attention.........................BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOBILE AL
229 PM CDT MON JUL 30 2012

THE NATIONAL WEATHER SERVICE IN MOBILE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
SOUTHERN OKALOOSA COUNTY IN NORTHWEST FLORIDA...
SOUTHEASTERN SANTA ROSA COUNTY IN NORTHWEST FLORIDA...

* UNTIL 315 PM CDT

* AT 227 PM CDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER
SIZE HAIL AND DAMAGING WINDS OVER 60 MPH WAS LOCATED 11 MILES
SOUTHWEST OF CRESTVIEW...OR 10 MILES SOUTH OF BAKER...AND MOVING
SOUTH AT 25 MPH.

* LOCATIONS IMPACTED INCLUDE...
OCEAN CITY... FORT WALTON BEACH... NAVARRE BEACH...
SHALIMAR... LAKE LORRAINE... CINCO BAYOU...
WRIGHT... VALPARAISO... NICEVILLE...

THIS INCLUDES INTERSTATE 10 BETWEEN MILE MARKERS 38 AND 66.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

CONTINUOUS CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM.
MOVE INDOORS IMMEDIATELY! IF YOU CAN HEAR THUNDER...YOU ARE CLOSE
ENOUGH TO BE STRUCK BY LIGHTNING.



LAT...LON 3073 8687 3078 8641 3061 8638 3045 8639
3044 8642 3048 8646 3045 8649 3042 8659
3040 8658 3040 8653 3042 8649 3042 8644
3041 8640 3038 8639 3039 8667 3037 8687
TIME...MOT...LOC 1930Z 355DEG 23KT 3064 8673
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Quoting MAweatherboy1:
This is from the SPC's latest discussion... It talks about the Carolina blob:

REGIONAL RADAR IMAGERY OVER NERN SC INDICATED AN AREA OF BROAD LOW
LEVEL CIRCULATION CENTERED OVER HORRY COUNTY SC...WITH THIS
CIRCULATION A SUB-SYNOPTIC LOW LOCATED ALONG A WIND SHIFT EXTENDING
NEWD FROM THE PRIMARY LOW OVER SERN GA. THE NERN SC LOW WILL ACT TO
ENHANCE LOW LEVEL SHEAR OVER NERN SC AND ERN NC AND...ANY
WATERSPOUTS FORMING OFFSHORE COULD POSE A THREAT AS THEY MOVE TOWARD
THE COAST WITHIN ELY LOW LEVEL FLOW ALONG THE TRACK OF THE SURFACE
LOW FROM NERN SC TO THE NC COAST.

Quoting ilovehurricanes13:
This is from the SPC's latest discussion... It talks about the Carolina blob:

REGIONAL RADAR IMAGERY OVER NERN SC INDICATED AN AREA OF BROAD LOW
LEVEL CIRCULATION CENTERED OVER HORRY COUNTY SC...WITH THIS
CIRCULATION A SUB-SYNOPTIC LOW LOCATED ALONG A WIND SHIFT EXTENDING
NEWD FROM THE PRIMARY LOW OVER SERN GA. THE NERN SC LOW WILL ACT TO
ENHANCE LOW LEVEL SHEAR OVER NERN SC AND ERN NC AND...ANY
WATERSPOUTS FORMING OFFSHORE COULD POSE A THREAT AS THEY MOVE TOWARD
THE COAST WITHIN ELY LOW LEVEL FLOW ALONG THE TRACK OF THE SURFACE
LOW FROM NERN SC TO THE NC COAST.

Creative post there, Jason.
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Quoting Grothar:


I've always had a fondness for models.


I will defer to your expertise since mine does not exzist, but I am learning!
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Blob off of the S.E coast wants to get in on the action as well...
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Not to bad now!!
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that pic is incredible....you dont get those over an island in the caribbean sea thats only 25 miles long!
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Quoting wunderkidcayman:


so far the models has shifted South not North and it 99L keeps on moving W-WNW the models should keep on moving West and South not North


good and die in the Carribean due to the strong tradewinds!
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Quoting GeorgiaStormz:
Panama City today:
..wow nice pic there
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this system has an awful lot to overcome...let alone get out of the itcz....that being said with the high in place and its already very low lattitude I doubt it making a turn sharp enough to miss the caribbean....it would have to start turning by tonight tomorrow...just dont see it. I think its coming in to the caribbean where it will likely die or just be a rainmaker...didnt the euro put it in the caribbean?
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Quoting LargoFl:
...........................................OK this is new...that Blob of the Carolinas now has a Blue light,might be a yellow circle sooner than expected
Agree maybe invest 90L tomorrow if it keeps improving.
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Panama City today:
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Quoting stormchaser19:

North in every way



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Quoting washingtonian115:
Gro it's a blob-a-thon going on right now.
yes and the WP is winning with 5 or 6 and the AT has 3.
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It appears as though 99L is trying to tighten up its circulation a bit. Also, the wave over the Antilles appears to have some vorticity over the Eastern Caribbean...and may have a chance to develop farther west as some have mentioned.
Link
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...........................................OK this is new...that Blob of the Carolinas now has a Blue light,might be a yellow circle sooner than expected
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North in every way

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Rare Mountain Tornado Touches Down Near Mount Evans

Link
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Gro it's a blob-a-thon going on right now.
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BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE JACKSONVILLE FL
308 PM EDT MON JUL 30 2012

THE NATIONAL WEATHER SERVICE IN JACKSONVILLE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
EASTERN CHARLTON COUNTY IN SOUTHEAST GEORGIA
WESTERN CAMDEN COUNTY IN SOUTHEAST GEORGIA
NORTHWESTERN NASSAU COUNTY IN NORTHEAST FLORIDA

* UNTIL 400 PM EDT

* AT 308 PM EDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
TRACKING A SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS
IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR HOMELAND...OR 6
MILES NORTHWEST OF FOLKSTON...AND MOVING EAST AT 15 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
HOMELAND...FOLKSTON AND KINGS FERRY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DOPPLER RADAR HAS INDICATED SOME WEAK ROTATION WITHIN THIS STORM.
WHILE NOT IMMEDIATELY LIKELY...A TORNADO MAY STILL DEVELOP. IF A
TORNADO IS SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A
STURDY STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM.

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...CONTINUOUS CLOUD TO
GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS
IMMEDIATELY! LIGHTNING IS ONE OF NATURES NUMBER ONE KILLERS.
REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE
STRUCK BY LIGHTNING.

REPORT SEVERE WEATHER OR DAMAGE TO THE NEAREST LAW ENFORCEMENT AGENCY
OR YOUR COUNTY EMERGENCY MANAGEMENT.

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Quoting Grothar:


That wouldn't be because you want it to go near you, is it?

no that is not why!
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Quoting Grothar:


That wouldn't be because you want it to go near you, is it?


I'd say so.

However, I'm not sold on northward movement. The high has been too strong this year. These trofs move into the W Atl and lift out quickly (or cut-off). I think the wave out ahead of 99L could be a good indication of what to expect, with maybe a little more interaction with the Greater Antilles.
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Quoting MississippiWx:
Still a good signature to this wave. Could be a problem once it gets into the Western Caribbean. It's currently in the graveyard of the Eastern Caribbean, so develop chances are low until it can move further west.

I know this is the NOGAPS we're talking about..but it did show something coming from this wave later on down the road.I'm not sure if it dropped it though.
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.................................funny thing about these storms, they come downstate in the gulf,come in, then head northeast,northern florida on the east side of the state is in for it
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Quoting RussianWinter:


As I said last night, an Andrew or a Floyd-like track would be the most dangerous. There is shear in the Caribbean but if this storm goes north it will avoid the shear.

no tracks into the Caribbean shear will not be any problem for it what so ever when it does
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Tropics might become a bit more interesting soon. I would expect better development at or after 60W.



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AL992012 - INVEST

Storm Relative 1km Geostationary Visible Imagery



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The only Caribbean hope for a medal in swimming is getting ready to swim now, a young lady from Jamaica, Alia Atkinson.

BTW, the BOSS place to check results on events is the official website...

Edit: and she just came 4th!!!! WOW!!!
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Quoting wunderkidcayman:


so far the models has shifted South not North and it 99L keeps on moving W-WNW the models should keep on moving West and South not North


That wouldn't be because you want it to go near you, is it?
Member Since: July 17, 2009 Posts: 71 Comments: 26865
I know this is a long way out..but but if 99L makes a turn north by Puerto Rico and avoids Hispanola completely then it has a chance to become maybe a minimal hurricane...IMO.
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Quoting Autistic2:


I don't think model tracks mean squat untill they at least a TD center to work off of.


I've always had a fondness for models.
Member Since: July 17, 2009 Posts: 71 Comments: 26865
Quoting Grothar:
Expect models to shift more North on each run.



so far the models has shifted South not North and it 99L keeps on moving W-WNW the models should keep on moving West and South not North
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Still a good signature to this wave. Could be a problem once it gets into the Western Caribbean. It's currently in the graveyard of the Eastern Caribbean, so develop chances are low until it can move further west.

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Quoting SFLWeatherman:
No it may go up to a Cat 3 if go up the east coast
99L need to develops first though. I would think Category 2-3 if it develops quickly in the next 24-36 hours and goes north. But if this storm takes awhile to develops and go north, I would expect at the most Category 1.
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Quoting Patrap:
Solution Pollution?

Analysis Paralysis
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Current steering. 99L will be going west for a while if this steering holds (which it won't be the same by the time it reaches the islands).

Interesting to see the energy off the East Coast splitting off from the main flow.

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Quoting Grothar:
Expect models to shift more North on each run.



I don't think model tracks mean squat untill they at least a TD center to work off of.
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Quoting LargoFl:
..more like up the east coast, this could be bad if this does unfold


A coast hugging storm (assuming it stays well off shore) isn't that bad (with the biggest threat being rip currents to beach goers and ), save for the Bahama people.
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No it may go up to a Cat 3 if go up the east coast
Quoting Bluestorm5:
At least it won't be as strong as Irene unless 99L suddenly decided to develops rapidly.
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Quoting Grothar:
Expect models to shift more North on each run.



As I said last night, an Andrew or a Floyd-like track would be the most dangerous. There is shear in the Caribbean but if this storm goes north it will avoid the shear.
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Member Since: July 17, 2009 Posts: 71 Comments: 26865
GFS ensembles

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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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