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 Stormchaser121:
Looks like the Western Gulf and TX might escape yet another hurricane season!

Not even close yet lol
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Quoting Doppler22:
Heres a poll for everybody (howevr if Patrap doesnt poll on a monday he doesnt have too ;)

At 8pm what will the % b on 99L?

A. 10-20% (Low)
B.30-40% (Medium)
C. 50% or greater(High)



B
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SHORT TERM FORECAST
NATIONAL WEATHER SERVICE SAN DIEGO CA
107 PM PDT MON JUL 30 2012

CAZ058-062-302100-
SAN DIEGO COUNTY MOUNTAINS-
SAN DIEGO COUNTY DESERTS-
107 PM PDT MON JUL 30 2012

.NOW...

AT 1 PM...A THUNDERSTORM WAS OVER NORTH COUNTY BETWEEN PALOMAR
MOUNTAIN AND WARNER SPRINGS AND WAS MOVING SOUTH AT 10 MPH TOWARD
LAKE HENSHAW. RADAR RAINFALL ESTIMATES SHOW ABOUT A THIRD OF AN INCH
OF RAIN FELL IN THIS AREA SINCE NOON. THUNDERSTORMS WERE ALSO
LOCATED OVER SOUTH COUNTY BETWEEN MORENO VILLAGE AND MOUNT LAGUNA.
Member Since: September 18, 2010 Posts: 0 Comments: 4570
Quoting Doppler22:
Heres a poll for everybody (howevr if Patrap doesnt poll on a monday he doesnt have too ;)

At 8pm what will the % b on 99L?

A. 10-20% (Low)
B.30-40% (Medium)
C. 50% or greater(High)

B. 40%
Member Since: October 22, 2011 Posts: 0 Comments: 2179
..just imagine..after 3-4 days of this HEAVY rainfall..getting a slow moving Tropical storm here in the southeast, and there is a wave coming Before that tropical something gets here
Member Since: August 6, 2011 Posts: 4 Comments: 33363
Quoting Doppler22:
Heres a poll for everybody (howevr if Patrap doesnt poll on a monday he doesnt have too ;)

At 8pm what will the % b on 99L?

A. 10-20% (Low)
B.30-40% (Medium)
C. 50% or greater(High)
B
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Member Since: July 21, 2011 Posts: 82 Comments: 7056
Quoting Bluestorm5:
We had been having heavy rain non-stop for 4 hours now. This was reported 5 miles from me.

RAH: 3 W Clayton

Time: 2012-07-30 20:50 UTC
Event: 2.25 HEAVY RAIN
Source: cocorahs
Remark: 2.15 inches of rain in 50 minutes at clayton 2.9 w. minor flooding of streets with water overflowing ditches onto the road. roads barely passable.
alot of flooding coming in the next few days alright
Member Since: August 6, 2011 Posts: 4 Comments: 33363
BAY AREA --
Heavy thunderstorms have been pounding Citrus County today.

Showers also have been affecting Hernando, Pasco and parts of Hillsborough County but the heaviest rainfall today has been affecting Citrus County.
As of 4:40 p.m., the following areas have seen this amount of rainfall.

Citrus County

Sugarmill Woods 3.02
Homosassa 5.09
Pine Ridge 3.76
Crystal River 4.58
Inverness 2.17
Lecanto 2.05
Hernando County

Brooksville 1.00
Hernando Beach 1.05
Spring Hill 1.34
Weeki Wachee 1.70
Pasco County

Hudson 0.80

New Port Richey 0.42

Dade City 0.40
Member Since: August 6, 2011 Posts: 4 Comments: 33363
i think B
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We had been having heavy rain non-stop for 4 hours now. This was reported 5 miles from me.

RAH: 3 W Clayton

Time: 2012-07-30 20:50 UTC
Event: 2.25 HEAVY RAIN
Source: cocorahs
Remark: 2.15 inches of rain in 50 minutes at clayton 2.9 w. minor flooding of streets with water overflowing ditches onto the road. roads barely passable.
Member Since: Posts: Comments:
Heres a poll for everybody (howevr if Patrap doesnt poll on a monday he doesnt have too ;)

At 8pm what will the % b on 99L?

A. 10-20% (Low)
B.30-40% (Medium)
C. 50% or greater(High)
Member Since: Posts: Comments:
Quoting SFLWeatherman:
99L is organizing now!!
this thing really want to achieve td status at least.
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BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE COLUMBIA SC
526 PM EDT MON JUL 30 2012

THE NATIONAL WEATHER SERVICE IN COLUMBIA HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
SOUTHERN CLARENDON COUNTY IN CENTRAL SOUTH CAROLINA
SOUTHEASTERN ORANGEBURG COUNTY IN CENTRAL SOUTH CAROLINA

* UNTIL 615 PM EDT

* AT 524 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS
OF 60 MPH. THIS STORM WAS LOCATED 9 MILES NORTHEAST OF HOLLY
HILL...OR 20 MILES NORTHWEST OF MONCKS CORNER...AND MOVING
SOUTHWEST AT 25 MPH.

* SOME COMMUNITIES IN THE WARNING AREA INCLUDE HOLLY HILL

REPORT LARGE HAIL...DAMAGING WINDS OR FLOODING TO YOUR COUNTY
SHERIFF...OR CALL THE NATIONAL WEATHER SERVICE...TOLL FREE 1 877 6 3
3...6 7 7 2.

LAT...LON 3343 8022 3339 8022 3338 8024 3330 8025
3326 8031 3327 8035 3325 8036 3325 8043
3328 8049 3333 8051 3323 8068 3328 8078
3351 8029 3344 8020
TIME...MOT...LOC 2126Z 044DEG 25KT 3338 8029
Member Since: August 6, 2011 Posts: 4 Comments: 33363
Member Since: July 3, 2005 Posts: 414 Comments: 125600
Member Since: July 21, 2011 Posts: 82 Comments: 7056
AL992012 - INVEST

Enhanced Infrared (IR) Imagery (4 km Mercator)




2km Storm Relative IR Imagery with BD Enhancement Curve



Member Since: July 3, 2005 Posts: 414 Comments: 125600
POSS T.C.F.A.
XX/INV/99L
MARK
9.85N/35.36W

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.................................whew,just keeps dumping tons of rain over the same area's
Member Since: August 6, 2011 Posts: 4 Comments: 33363
99L is organizing now!!
Member Since: May 23, 2012 Posts: 0 Comments: 4207
Quoting Patrap:
AL992012 - INVEST

Storm Relative 1km Geostationary Visible Imagery




Lost sunlight
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Quoting Grothar:


Gee, I guess I'm wrong. How embarrassing.
Grother..... I guess the rookies keep you in your place...........NOT
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747. JLPR2
Quoting DataNerd:



That's heading right into an area of very high shear don't expect it to be there in 14 hours.


It is currently in an area of high shear 30-35knots.

Quoting allancalderini:
If it moves NW instead of W it would had a better chance of surviving and then developing.


ULL to its North wouldn't help, unless it retreated to the east/north-east.
Member Since: September 4, 2007 Posts: 7 Comments: 8459
Quoting Stormchaser121:
Looks like the Western Gulf and TX might escape yet another hurricane season!

Ya nvr know... we still have until November 30th which is a while even though the chance decreases ovr time anything can happen... Mother nature will do whatever the heck she wants no matter when
Quoting ilovehurricanes13:
wow!!

wow is right... that may affect me... and im not in a hurricane mood :p
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AL992012 - INVEST

Storm Relative 1km Geostationary Visible Imagery

Member Since: July 3, 2005 Posts: 414 Comments: 125600
Member Since: August 6, 2011 Posts: 4 Comments: 33363
Rain for me!!:)
Member Since: May 23, 2012 Posts: 0 Comments: 4207
Not that I'm speculating, but IF, and when I say if I mean when, Ernesto crashes into the US as a major hurricane, I say we replace his name with Enzo in 2018.
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I have never seen such panic since I was in 3rd grade wondering who was going to get to bang out the erasers..... Lot's of time left rookies.....Calm down.
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Quoting Stormchaser121:
Looks like the Western Gulf and TX might escape yet another hurricane season!

It's July 30. Texas is at risk until November 30.
Member Since: Posts: Comments:
BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MELBOURNE FL
457 PM EDT MON JUL 30 2012

THE NATIONAL WEATHER SERVICE IN MELBOURNE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
NORTH CENTRAL OSCEOLA COUNTY IN FLORIDA

* UNTIL 545 PM EDT.

* AT 455 PM EDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS
OF 60 MPH. THIS STORM WAS LOCATED NEAR WEST LAKE TOHO...AND MOVING
NORTHEAST AT 10 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE...BUT ARE NOT LIMITED TO...
SAINT CLOUD...NARCOOSSE...EAST LAKE TOHO.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS IN EXCESS OF 58 MILES AN
HOUR AND OR LARGE DESTRUCTIVE HAIL. FREQUENT TO EXCESSIVE LIGHTNING
AND VERY HEAVY RAIN WILL ALSO BE POSSIBLE. IF THE STORM APPROACHES
YOU...SEEK SHELTER IN AN ENCLOSED BUILDING ON THE LOWEST FLOOR. KEEP
AWAY FROM WINDOWS.
Member Since: August 6, 2011 Posts: 4 Comments: 33363
Quoting AllStar17:


Oh, I'm not saying don't discuss track. But obviously right now it is all just speculation.


Hey, AllStar!! You know we never speculate on this blog.
Member Since: July 17, 2009 Posts: 63 Comments: 23722
Quoting Grothar:


Gee, I guess I'm wrong. How embarrassing.



Not at all xD

Anything is possible this early in the game. That's what makes it interesting.
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Quoting SFLWeatherman:
HPC day 7



GFS basically
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HPC day 7

Member Since: May 23, 2012 Posts: 0 Comments: 4207
Quoting DataNerd:



GFS 012 run is showing due west. HWREF is showing due west. Quite a few still taking it west.

NW component is not just contingent on the trough, its not expected to be strong enough to induce that on its own for a system so far south, we would need a moderate to deep cyclone as well, strong ts-cat1 hurricane to feel that influence and it would need to be at that strength around 85 hours. I don't see that happening because we don't have a td now.


Gee, I guess I'm wrong. How embarrassing.
Member Since: July 17, 2009 Posts: 63 Comments: 23722
Just watched the local met,he says north florida for the next 3 or 4 days is going to get alot of heavy rain,with that onshore flow off the very warm gulf with all that tropical moisture...folks..remember what happened a few months ago
Member Since: August 6, 2011 Posts: 4 Comments: 33363
Looks like the Western Gulf and TX might escape yet another hurricane season!
Member Since: Posts: Comments:
No Active Atlantic Tropical Warnings
July-30-12, 5:15:02 PM | Maritime.CDO@navy.mil (FWC-N CDO)
As of Mon, 30 Jul 2012 21:15:02 GMT
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Quoting JLPR2:
This TW's convection isn't moving and isn't looking that bad either.

If it moves NW instead of W it would had a better chance of surviving and then developing.
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Quoting JLPR2:
This TW's convection isn't moving and isn't looking that bad either.




That's heading right into an area of very high shear don't expect it to be there in 14 hours.
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706

WHXX01 KWBC 301936

CHGHUR

TROPICAL CYCLONE GUIDANCE MESSAGE

NWS NATIONAL HURRICANE CENTER MIAMI FL

1936 UTC MON JUL 30 2012



DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.

PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE

AND SUBTROPICAL CYCLONE INFORMATION.



ATLANTIC OBJECTIVE AIDS FOR



DISTURBANCE INVEST (AL992012) 20120730 1800 UTC



...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...

120730 1800 120731 0600 120731 1800 120801 0600



LAT LON LAT LON LAT LON LAT LON

BAMS 8.7N 35.8W 9.1N 38.9W 9.6N 42.2W 9.6N 45.7W

BAMD 8.7N 35.8W 8.8N 37.7W 9.0N 39.6W 9.4N 41.5W

BAMM 8.7N 35.8W 8.9N 38.0W 9.3N 40.3W 9.6N 42.6W

LBAR 8.7N 35.8W 8.7N 37.5W 8.9N 39.7W 9.1N 42.0W

SHIP 20KTS 22KTS 27KTS 34KTS

DSHP 20KTS 22KTS 27KTS 34KTS



...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...

120801 1800 120802 1800 120803 1800 120804 1800



LAT LON LAT LON LAT LON LAT LON

BAMS 9.4N 49.1W 8.4N 54.7W 7.8N 59.3W 7.9N 62.5W

BAMD 9.8N 43.4W 10.5N 47.0W 11.9N 51.1W 14.3N 56.5W

BAMM 10.0N 44.7W 10.7N 48.7W 11.8N 52.8W 13.4N 57.6W

LBAR 9.3N 44.5W 9.4N 49.2W 10.0N 53.4W 12.4N 57.7W

SHIP 45KTS 63KTS 72KTS 75KTS

DSHP 45KTS 63KTS 72KTS 75KTS



...INITIAL CONDITIONS...

LATCUR = 8.7N LONCUR = 35.8W DIRCUR = 270DEG SPDCUR = 4KT

LATM12 = 8.7N LONM12 = 35.1W DIRM12 = 270DEG SPDM12 = 4KT

LATM24 = 8.7N LONM24 = 34.4W

WNDCUR = 20KT RMAXWD = 80NM WNDM12 = 20KT

CENPRS = 1010MB OUTPRS = 1011MB OUTRAD = 160NM SDEPTH = S

RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM



$$

NNNN
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Quoting TropicalAnalystwx13:

Slowly organizing.
Alright, thanks!I don't know too much about the development phase of cyclones so I thought I would ask.
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This looks like fun:

hot

So does this...

hot

and most of all this:

hot
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do anyone know if the remanents of Daniel help to form ts Damrey or they dissipate.
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722. JLPR2
This TW's convection isn't moving and isn't looking that bad either.

Member Since: September 4, 2007 Posts: 7 Comments: 8459
Quoting Bluestorm5:
So what's the health of 99L right now? Is it getting stronger or weaker?



Some people thinking 30% chance upgrade by 8.

More convection but no real structural change yet besides that. Will be watching overnight and into tomorrow to see where it goes.


I'll go out on a limb and say that I agree it could be set at 30% chance by 8 if current trends continue. Visible appearance looking a bit better now.
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Quoting Bluestorm5:
So what's the health of 99L right now? Is it getting stronger or weaker?

Slowly organizing.
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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.