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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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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Quoting JLPR2:


I hope that trend stops and reverts.


99L is moving at 00z west at 280 degrees. On 18z it was at 275 degrees so a slight north component.
Member Since: April 29, 2009 Posts: 75 Comments: 14000
Quoting Civicane49:
Repost for those who missed my blog entry earlier today.



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 all the best in your endeavors.
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Quoting Grothar:
Moving ever so slightly WNW on each run.


Comparison:
The consensus of the models yesterday:
Southern Leewards-Trinidad.
The Consensus of the models today:
Upper leeward islands.
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1166. ackee
MOst OF the model has shift further south tonight and I think what ever become of 99L will move into the CARRBEAN and be shear apart that the most likely track to me. I see a weak TS the most from this hopfuly AUG will bring something worth tracking
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1164. Gearsts
Quoting JLPR2:


Where are you? Does your area need the rain bad? At least in my area, Carolina almost at San Juan everything seems green and the creek close to my street seems normal.

Also an ULL to the NE of a system, hmm... XD
ULL cant help our system? I live in Aguadilla and im bored of sunshine everyday.
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Quoting Grothar:


How very fortunate. :)


I resemble that remark!
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Quoting HurricaneDean07:

Has bumped up .2 degrees north...
Heading due west, with a slight northerly component, like i said :)


Moving west at 280 degrees.
Member Since: April 29, 2009 Posts: 75 Comments: 14000
Quoting Grothar:


Beard???
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...
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8PM
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1159. JLPR2
Quoting Grothar:
Moving ever so slightly WNW on each run.



I hope that trend stops and reverts.
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Seems like all convection goes into vanishing WV...

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1157. Gearsts
Quoting Grothar:
Moving ever so slightly WNW on each run.

So that's means that they see it stronger as it aproches the islands?
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MAweatherboy1: Tuesday's tomorrow Gro... You think it could develop that fast?
1137 Grothar: Late Tuesday.

Would certainly UP the probability of TD.5 (or Ernesto) making passage through the northern LesserAntilles.
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Quoting Tropicsweatherpr:
00z Best Track.

AL, 99, 2012073100, , BEST, 0, 89N, 366W, 20, 1010, DB

Has bumped up .2 degrees north...
Heading due west, with a slight northerly component, like i said :)
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1154. Grothar
Quoting HurricaneDean07:

lol


I knew it!
Member Since: July 17, 2009 Posts: 69 Comments: 25333
1153. JLPR2
Quoting Gearsts:
ULL will stay behind and help the anticyclone build over our system better.And i hope we get the tail off our wave tonight and tomorrow.


Where are you? Does your area need the rain bad? At least in my area, Carolina almost at San Juan everything seems green and the creek close to my street seems normal.

Also an ULL to the NE of a system, hmm... XD
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1152. Grothar
Quoting stormwatcherCI:
I am not Geoff but no there is no chance. We have not sent an invitation to any tropical disturbance this year.


How very fortunate. :)
Member Since: July 17, 2009 Posts: 69 Comments: 25333
Quoting TropicalAnalystwx13:

Shred to pieces by what? The shear that doesn't exist? XD


No explanation.... thinking....

Unless!!!!

AHHHH,

It should be the HAARP thing.... must be that....
Any HAARP technician on the blog? ;)

(if you don't know the anwser - blame it to HAARP)
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1150. Gearsts
Quoting JLPR2:


That should help if it moves in tandem with 99L, now that you mention this it might have a chance but that ULL at 30N seems stuck there.
ULL will stay behind and help the anticyclone build over our system better.And i hope we get the tail off our wave tonight and tomorrow.
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99L needs to detach from the ITCZ for any development. The NHC won't increase chances until that happens. The invest still has a long way to go in terms of development and It was never a shoe in to begin with.
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1148. Grothar
Moving ever so slightly WNW on each run.

Member Since: July 17, 2009 Posts: 69 Comments: 25333
Quoting Grothar:


Hey, Geoff, any chance this could make it to the Cayman Islands?
I am not Geoff but no there is no chance. We have not sent an invitation to any tropical disturbance this year.
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AL, 99, 2012073006, 87N, 351W, 20, 1010, DB
AL, 99, 2012073012, 87N, 355W, 20, 1010, DB
AL, 99, 2012073018, 87N, 358W, 20, 1010, DB
AL, 99, 2012073100, 89N, 366W, 20, 1010, DB
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1145. SLU


925

WHXX01 KWBC 310032

CHGHUR

TROPICAL CYCLONE GUIDANCE MESSAGE

NWS NATIONAL HURRICANE CENTER MIAMI FL

0032 UTC TUE JUL 31 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) 20120731 0000 UTC



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

120731 0000 120731 1200 120801 0000 120801 1200



LAT LON LAT LON LAT LON LAT LON

BAMS 8.9N 36.6W 9.5N 39.9W 10.0N 43.3W 10.1N 47.0W

BAMD 8.9N 36.6W 9.1N 38.6W 9.6N 40.6W 10.1N 42.5W

BAMM 8.9N 36.6W 9.4N 38.8W 10.0N 41.2W 10.6N 43.5W

LBAR 8.9N 36.6W 9.1N 38.7W 9.6N 41.3W 9.9N 44.0W

SHIP 20KTS 24KTS 30KTS 40KTS

DSHP 20KTS 24KTS 30KTS 40KTS



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

120802 0000 120803 0000 120804 0000 120805 0000



LAT LON LAT LON LAT LON LAT LON

BAMS 9.7N 50.4W 8.9N 56.6W 8.2N 62.2W 8.5N 66.9W

BAMD 10.6N 44.5W 11.5N 48.3W 13.1N 52.7W 15.4N 58.0W

BAMM 11.1N 45.8W 11.9N 50.3W 12.9N 55.1W 14.0N 60.4W

LBAR 10.1N 46.6W 10.2N 51.8W 10.6N 56.4W 12.7N 59.2W

SHIP 47KTS 60KTS 66KTS 66KTS

DSHP 47KTS 60KTS 66KTS 66KTS



...INITIAL CONDITIONS...

LATCUR = 8.9N LONCUR = 36.6W DIRCUR = 280DEG SPDCUR = 8KT

LATM12 = 8.7N LONM12 = 35.5W DIRM12 = 270DEG SPDM12 = 3KT

LATM24 = 8.7N LONM24 = 34.7W

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

CENPRS = 1010MB OUTPRS = 1011MB OUTRAD = 150NM SDEPTH = S

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



$$

NNNN

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Quoting Grothar:


Hey, Civi! I go away a lot but I always find a few minutes to check in. You just can't leave us and not check in once in a while.


I will try to stop by here as I can, if time permits.

I will still be here until late in this evening.
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00z Best Track.

AL, 99, 2012073100, , BEST, 0, 89N, 366W, 20, 1010, DB
Member Since: April 29, 2009 Posts: 75 Comments: 14000
1142. Grothar
Quoting BahaHurican:
Comes from being everybody's great-grandfather figure... we r the cheeky kids pulling the beard... lol


Beard???
Member Since: July 17, 2009 Posts: 69 Comments: 25333
Quoting presslord:
This is nasty!!!
Hey Presslord.Hope you have preparations in order for your hurricane kit/plans.
Member Since: August 14, 2010 Posts: 10 Comments: 16406
1140. Grothar
Quoting Civicane49:


Thanks, Articuno.


Hey, Civi! I go away a lot but I always find a few minutes to check in. You just can't leave us and not check in once in a while.
Member Since: July 17, 2009 Posts: 69 Comments: 25333
Quoting Grothar:


Oh, so you did read my blog. :)

lol
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Quoting Grothar:


Late Tuesday.

Great minds think alike.
That's my guess.
Member Since: October 22, 2011 Posts: 0 Comments: 2293
1137. Grothar
Quoting MAweatherboy1:

Tuesday's tomorrow Gro... You think it could develop that fast?


Late Tuesday.
Member Since: July 17, 2009 Posts: 69 Comments: 25333
1136. JLPR2
Quoting Hurricanes101:


anticyclone is also starting to take shape over 99L



That should help if it moves in tandem with 99L, now that you mention this it might have a chance but that ULL at 30N seems stuck there.
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Quoting Grothar:


When the frost is on the pumpkin......


LOL
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Quoting Grothar:


It is in a way. I am generally very quiet and reserved. I say things on here I would never say otherwise. Alter-ego type of thing. I feel very comfortable here (most of the time). The last place I thought I would spend my golden years was on a weather blog. But I have grown fond of a lot of the bloggers. I enjoy the ribbing best. Most people are quite reticent to say the things you all say to me.
Comes from being everybody's great-grandfather figure... we r the cheeky kids pulling the beard... lol
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1133. Grothar
Quoting GeoffreyWPB:


30 days has September, April, June and November.


When the frost is on the pumpkin......
Member Since: July 17, 2009 Posts: 69 Comments: 25333
1132. Grothar
Quoting HurricaneDean07:

I think "Ernesto" will be positioned exactly where the tropical wave in front of it is, by the weekend.


Oh, so you did read my blog. :)
Member Since: July 17, 2009 Posts: 69 Comments: 25333
Quoting JLPR2:


Take a close look above 10N at 35-40W and onward.



CATL above 10N int exactly favorable, it needs to ride low to have a chance.


anticyclone is also starting to take shape over 99L

Member Since: March 10, 2010 Posts: 1 Comments: 7361
1130. Grothar
Quoting spathy:


Thats for sure.
Its kinda comforting if you think about it.


It is in a way. I am generally very quiet and reserved. I say things on here I would never say otherwise. Alter-ego type of thing. I feel very comfortable here (most of the time). The last place I thought I would spend my golden years was on a weather blog. But I have grown fond of a lot of the bloggers. I enjoy the ribbing best. Most people are quite reticent to say the things you all say to me.
Member Since: July 17, 2009 Posts: 69 Comments: 25333
Quoting Grothar:


Yes, but what month?


30 days has September, April, June and November.
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The GFDL/HWRF didn't ran at 18Z right? I ask as I dont see their sites updated.
Member Since: April 29, 2009 Posts: 75 Comments: 14000
Quoting Grothar:


Yes, but what month?

July.
Member Since: July 6, 2010 Posts: 113 Comments: 31437
I am anxious to see the 8 p.m. model runs on 99L. (I guess a lot of us are!) So much divergence of opinion on this one. I guess that's per usual. I've been a member of this site for years. I don't post a lot, but I read as many comments as I can several times a day in season when there's an AOI.

Accuweather says that if it goes into the Caribbean, it will go poof. It only has a chance, according to them, if it goes north of the islands. The winds out the west are too strong for a southern track.
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Quoting HurricaneDean07:

I think "Ernesto" will be positioned exactly where the tropical wave in front of it is, by the weekend.

I agree.
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1124. Patrap
There are now 143 Days until the 2012 Winter Solstice.

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1123. Grothar
Quoting HurricaneDean07:

Grothar... Tomorrow's Tuesday.


Yes, but what month?
Member Since: July 17, 2009 Posts: 69 Comments: 25333
Quoting Articuno:

I will miss you. visit back often. I respect all waht you do here, your on my respected bloggers list.


Thanks, Articuno.
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Quoting Grothar:


Hey, Geoff, any chance this could make it to the Cayman Islands?


Grothar/ Geoff- I certainly hope not,but we are watching closely in the days ahead
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1120. JLPR2
Quoting Tazmanian:



nop its at 9.0N

30/1745 UTC 9.0N 37.1W TOO WEAK 99L


Don't trust satellite estimates on storm positions. xD

AL, 99, 2012073018, , BEST, 0, 87N, 358W, 20, 1010, DB
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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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