Two African waves, 92L and 93L, worth watching

By: Dr. Jeff Masters , 2:59 PM GMT on August 11, 2011

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An African wave is near 13°N 35°W, about 700 miles west-southwest of the Cape Verde Islands. This system, (Invest 92L), is moving west to west-northwest at 10 - 15 mph, and has the potential to develop into a tropical depression or tropical storm before arriving near the northern Lesser Antilles Islands early next week. Recent visible satellite loops show that 92L has less heavy thunderstorm activity near where it is trying to develop its circulation center than yesterday. Water vapor satellite loops that a large area of dry air lies just to the west of 92L, but the atmosphere in the immediate vicinity of 92L is moist. Even so, the decline of heavy thunderstorm activity since yesterday implies that dry air is probably working its way into 92L. The SHIPS model and University of Wisconsin CIMSS wind shear analysis are showing moderate wind shear of 10 - 15 knots affecting 92L. Sea surface temperatures are 26.5° - 27°C, which is very close to the 26.5°C threshold usually needed to support a tropical storm.


Figure 1. Morning satellite photo of Invest 92L and Invest 93L.

Forecast for 92L
Low to moderate wind shear of 5 - 15 knots is predicted along 92L's path over the coming three days, which should allow the storm to organize, assuming it can shut out any incursions of dry air that might intrude. The latest 00Z and 06Z model runs of the four best models for predicting tropical storm formation (GFS, ECMWF, NOGAPS, and UKMET) show weak development or no development of 92L, and NHC gave 92L a 30% chance of developing into a tropical depression by Saturday morning in their 8am outlook. A steady west to west-northwest motion for 92L is predicted by all of the models, which would put the storm in the vicinity of the northern Lesser Antilles Islands by Sunday. On Saturday and Sunday, 92L is expected to enter a region where an upper-level low pressure system will bring high wind shear of 20 knots to the storm, which should slow development. This upper-level low is also expected to turn 92L more to the northwest, so the storm is likely to pass north of the Lesser Antilles, though may pass close enough to give heavy rains to the northernmost islands. It is too early to know if 92L will recurve out to sea and potentially threaten Bermuda, or continue to the northwest towards the U.S. East Coast.

93L
An African wave that emerged off the coast of Africa is near 10°N 22°W, a few hundred miles south of the Cape Verde Islands. This system, (Invest 93L), is also moving west at 10 - 15 mph, and has the potential to develop into a tropical depression or tropical storm before arriving near the northern Lesser Antilles Islands near the middle of next week. Recent visible satellite loops show that 93L has a decent amount of heavy thunderstorms, but this activity is not well organized. There is not much spin associated with 93L yet. 93L is fairly well-protected from dry air to its north and west. The SHIPS model and University of Wisconsin CIMSS wind shear analysis are showing moderate wind shear of 10 - 20 knots affecting 93L. Sea surface temperatures are 27.5°C, which is one degree above the 26.5°C threshold usually needed to support a tropical storm.

Forecast for 93L
Moderate wind shear below 20 knots is predicted along 93L's path over the coming five days, which should allow the storm to steadily organize. 93L is about 600 miles east of 92L, which is close enough that the two systems may interfere with each others' organization. The latest 00Z and 06Z model runs of the four best models for predicting tropical storm formation (GFS, ECMWF, NOGAPS, and UKMET), have only one model, the GFS, that is indicating significant development of 93L. This model brings 93L near the northern Lesser Antilles Islands by Wednesday. NHC gave 93L a 20% chance of developing into a tropical depression by Saturday morning in their 8am outlook. Due to moister air, the potential for less wind shear, and a more southerly track, 93L is probably a greater threat to the Lesser Antilles than 92L.

Jeff Masters

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958. OceanMoan
1:36 AM GMT on August 12, 2011
Quoting tiggeriffic:
ok...left for a bit to come back and find this model...yes, i know it is a long way off...yes, i know they change daily...it was just one of those things to top off the already bad day that I had... i mean...come on...but then again...if you believe in the premise that storms have cycles to hit every so many years...then our area is WAY over due...

Link


That is an unsettling image!
Member Since: September 7, 2007 Posts: 0 Comments: 231
957. pottery
1:36 AM GMT on August 12, 2011
Quoting txjac:


lol ...love it ...is that anything like a wet cold?

LOL...
But seriously, I visited Arizona when the Temps were low hundreds.
Low humidity, and I had no problem with that.
Here it has been mid 90's all week with Humidity in the 70-80 range.

You FEEL that...
Member Since: October 24, 2005 Posts: 0 Comments: 23902
956. kmanislander
1:34 AM GMT on August 12, 2011
Quoting pottery:

Hi.
Got 3 mm of rain today....
Been feeling like April this last 2 weeks.
I see that you are surrounded by clear skies as well.
Hope you get some showers, without any Name attached.


LOL. Actually we got quite a bit today with lots of T & L. Purely a local event that barely showed up on satellite but very impressive to see. I witnessed several significant lightning discharges over the cruise ships in harbour and then later ( around 6 our time ) over my neighbourhood.

You certainly didn't want to be outside holding an umbrella !
Member Since: August 19, 2006 Posts: 0 Comments: 15687
955. bohonkweatherman
1:34 AM GMT on August 12, 2011
I have been told by people that have gone to Florida that their humidity is off the charts? I have been to Georgia, La and South Carolina and their humidity was worse than here in Texas. Am I wrong about Florida?
Member Since: July 5, 2009 Posts: 0 Comments: 1348
954. Grothar
1:33 AM GMT on August 12, 2011
This was from two years ago.

Hottest temperatures ever recorded in South Florida.

Robert Jones, Miami Weather Examiner
June 22, 2009

A heat advisory is in effect until 7 PM tonight and we could be near the all-time record highs. That means we will be near the hottest temperatures that have ever been recorded in South Florida. The highest ever recorded in Miami and Ft. Lauderdale was 100 degrees back on July 21, 1942 and August 4, 1944 respectively. West Palm Beach's highest recorded temperature was 101 degrees on July 21, 1942 as well. Yesterday records were broke all across South Florida and Ft. Lauderdale shattered their old record by 4 degrees with a high of 98, hottest June temperature ever recorded.



Member Since: July 17, 2009 Posts: 68 Comments: 25086
952. txjac
1:32 AM GMT on August 12, 2011
Quoting twincomanche:
It's a dry heat.


lol ...love it ...is that anything like a wet cold?
Member Since: April 24, 2010 Posts: 1 Comments: 2442
951. angiest
1:32 AM GMT on August 12, 2011
Quoting Grothar:


I don't know why everyone thinks Florida is that humid. I know of a lot more places where the humidity is stiffling (too tired to look up correct spelling). Especially in Southern Florida, we never get temperatures that high. I don't know how you can stand that kind of heat for so long.


People from Dallas think the same about Houston. Having grown up in the former and lived for over a decade in the latter, I *know* that summer is typically worse in Dallas, where it is only slightly less humid but several degrees hotter (average highs in Houston peak at 94 or 95, and at 98 or 99 in Dallas). The air in Dallas this past weekend was blistering.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting bohonkweatherman:
Suppose to strengthen by this weekend thru next week and most likely the rest of August is what I am hearing from local weathermen. Today it was above 100 with very high humidity and heat index of 114. Sorry but i cannot see how Florida can deal with their humidity, there was no rain here within 100 miles. Every heat record locally will by smashed by end of September in Texas


I'm in FL and the humidity is HORRIBLE.
Heat index is 110 tomorrow and thats just for the shade. In the sun the heat index is 15 degrees higher.
Member Since: June 23, 2010 Posts: 0 Comments: 583
Quoting kmanislander:
Good evening folks

Climatology for lows where 92 and 93L are favour 92L to recurve without hitting the NE Caribbean or the SE US ( probably 75% on that ) and 50/50 for 93L based again on current position. Model runs still mean very little at this point in time save that the forecast for the mid Atlantic high has it building back in after 92L recurves and this would drive 93L into the Islands if it holds. We are several days away from anything definitive.

Hi.
Got 3 mm of rain today....
Been feeling like April this last 2 weeks.
I see that you are surrounded by clear skies as well.
Hope you get some showers, without any Name attached.
Member Since: October 24, 2005 Posts: 0 Comments: 23902


Dr. Masters should use this map in his update tomorrow. He usually does for Cape Verde storms.
Member Since: July 6, 2010 Posts: 112 Comments: 31336
Member Since: Posts: Comments:
Quoting txjac:


I'm south of you by about 8-10 miles ...feeling your pain!


I'm noticing trees in George Bush Park (my commute goes through there) have started dying.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
High Pressure moved west for 2 days by Saturday unfortunately it moves back over heart of Texas and sits for awhile. http://www.kxan.com/subindex/weather/7_day_forecas t
Member Since: July 5, 2009 Posts: 0 Comments: 1348
Quoting bohonkweatherman:
Suppose to strengthen by this week thru next week and most likely the rest of August is what I am hearing from local weathermen. Today it was above 100 with very high humidity and heat index of 114. Sorry but i cannot see how Florida can deal with their humidity, there was no rain here within 100 miles. Every heat record locally will by smashed by end of September in Texas


I don't know why everyone thinks Florida is that humid. I know of a lot more places where the humidity is stiffling (too tired to look up correct spelling). Especially in Southern Florida, we never get temperatures that high. I don't know how you can stand that kind of heat for so long.
Member Since: July 17, 2009 Posts: 68 Comments: 25086
Quoting TropicalAnalystwx13:


The link was messed up some, so I fixed it.

Link


Thanks
Member Since: June 23, 2010 Posts: 0 Comments: 583
941. txjac
Quoting angiest:


The town I live in, Katy, has officially recorded no rain for the last two months.


I'm south of you by about 8-10 miles ...feeling your pain!
Member Since: April 24, 2010 Posts: 1 Comments: 2442
ok...left for a bit to come back and find this model...yes, i know it is a long way off...yes, i know they change daily...it was just one of those things to top off the already bad day that I had... i mean...come on...but then again...if you believe in the premise that storms have cycles to hit every so many years...then our area is WAY over due...

Link
Member Since: September 16, 2007 Posts: 0 Comments: 3650
Quoting txjac:


I was wondering if you got any of that rain that appeared to be falling in west Texas ...guess not, sorry


The town I live in, Katy, has officially recorded no rain for the last two months.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Good evening folks

Climatology for lows where 92 and 93L are favour 92L to recurve without hitting the NE Caribbean or the SE US ( probably 75% on that ) and 50/50 for 93L based again on current position. Model runs still mean very little at this point in time save that the forecast for the mid Atlantic high has it building back in after 92L recurves and this would drive 93L into the Islands if it holds. We are several days away from anything definitive.
Member Since: August 19, 2006 Posts: 0 Comments: 15687
935. txjac
Quoting bohonkweatherman:
Suppose to strengthen by this week thru next week and most likely the rest of August is what I am hearing from local weathermen. Today it was above 100 with very high humidity and heat index of 114. Sorry but i cannot see how Florida can deal with their humidity, there was no rain here within 100 miles. Every heat record locally will by smashed by end of September in Texas


I was wondering if you got any of that rain that appeared to be falling in west Texas ...guess not, sorry
Member Since: April 24, 2010 Posts: 1 Comments: 2442
Quoting thunderbug91:
http://www.opc.ncep.noaa.gov/sst/images/gmex/GMex _G oesENH.gif



The GOM is quite warm for the first tropical system that enters it....


The brutal heat wave over the NE may have been the best opportunity of the season for the Gulf, at least the western Gulf. We certainly had some disturbances come around the southern edge of the ridge, but nothing of any substance took advantage of it.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting thunderbug91:
http://www.opc.ncep.noaa.gov/sst/images/gmex/GMex _G oesENH.gif



The GOM is quite warm for the first tropical system that enters it....


The link was messed up some, so I fixed it.

Link
Member Since: July 6, 2010 Posts: 112 Comments: 31336
Quoting TropicalAnalystwx13:
The Texas ridge is getting soft.

Suppose to strengthen by this weekend thru next week and most likely the rest of August is what I am hearing from local weathermen. Today it was above 100 with very high humidity and heat index of 114. Sorry but i cannot see how Florida can deal with their humidity, there was no rain here within 100 miles. Every heat record locally will by smashed by end of September in Texas
Member Since: July 5, 2009 Posts: 0 Comments: 1348
Quoting brazocane:


20% sunday lol


20% chance of a very heavy dew is more like it.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting txjac:
Well heck, I was starting to get excited until I read angiest's post ...


20% sunday lol
Member Since: Posts: Comments:
http://www.opc.ncep.noaa.gov/sst/images/gmex/GMex_G oesENH.gif



The GOM is quite warm for the first tropical system that enters it....
Member Since: June 23, 2010 Posts: 0 Comments: 583
Quoting TropicalAnalystwx13:

lol, that is the truth.



18Z GFS @ 192 hours: 1000 MB to the north of Puerto Rico.


^Invest 93L.

Quoting aislinnpaps:


Now that is depressing. We can't even have the kids out for recess for more than ten minutes in this heat. Not Houston here, but close in temps.


Are you a teacher?
Member Since: July 6, 2010 Posts: 112 Comments: 31336
927. txjac
Well heck, I was starting to get excited until I read angiest's post ...
Member Since: April 24, 2010 Posts: 1 Comments: 2442
Member Since: July 17, 2009 Posts: 68 Comments: 25086
Tornado on the Ground




08/11/2011 0805 PM
3 miles se of Wood Lake, Cherry County.
Tornado, reported by trained spotter.
Estimating tornado being a quarter mile wide and have seen damage along tornado path.

08/11/2011 0800 PM
1 miles S of Wood Lake, Cherry County.
Tornado, reported by trained spotter.
Debris in the air and possibly becoming rain wrapped.

08/11/2011 0749 PM
1 miles W of Wood Lake, Cherry County.
Tornado, reported by trained spotter.
Spotter was seeing debris flying under The Funnel.
Member Since: Posts: Comments:
Quoting MississippiWx:


Well, that's more convection than Don could provide.

Ain't that the truth...
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Member Since: July 17, 2009 Posts: 68 Comments: 25086
Quoting caneswatch:


Up to a strong Cat. 2 by Tuesday.



wow
Member Since: May 21, 2006 Posts: 5091 Comments: 114653
Quoting WeatherNerdPR:

Geez, that ridge better break down soon or Texas will turn into America's Sahara.


Sadly, those highs are only about 4-5 degrees above normal. You can hit those on any random summer day in Houston, but to have it happen every day for months (with excursions to 10 above normal).
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting angiest:


Not so much in Houston:


Tonight: Partly cloudy, with a low around 80. South wind between 5 and 10 mph.

Friday: Mostly sunny and hot, with a high near 100. Heat index values as high as 108. South wind between 5 and 15 mph.

Friday Night: Partly cloudy, with a low around 80. South wind between 5 and 15 mph.

Saturday: Mostly sunny and hot, with a high near 100. Heat index values as high as 105. South wind between 5 and 10 mph.

Saturday Night: Partly cloudy, with a low around 78. South wind between 5 and 10 mph.

Sunday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny and hot, with a high near 100.

Sunday Night: A 20 percent chance of showers and thunderstorms before 10pm. Partly cloudy, with a low around 78.

Monday: Mostly sunny and hot, with a high near 99.

Monday Night: Partly cloudy, with a low around 78.

Tuesday: Mostly sunny and hot, with a high near 99.

Tuesday Night: Partly cloudy, with a low around 78.

Wednesday: Mostly sunny and hot, with a high near 100.

Wednesday Night: Partly cloudy, with a low around 78.

Thursday: Sunny and hot, with a high near 100.


Now that is depressing. We can't even have the kids out for recess for more than ten minutes in this heat. Not Houston here, but close in temps.
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Here's a pretty for ya :)


Member Since: September 16, 2010 Posts: 0 Comments: 1492
Quoting MississippiWx:


Well, that's more convection than Don could provide.


lol, that is the truth.



18Z GFS @ 192 hours: 1000 MB to the north of Puerto Rico.
Member Since: July 6, 2010 Posts: 112 Comments: 31336
Quoting caneswatch:


Up to a strong Cat. 2 by Tuesday.


And 91L was supposed to be 120mph.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting angiest:


Not so much in Houston:


Tonight: Partly cloudy, with a low around 80. South wind between 5 and 10 mph.

Friday: Mostly sunny and hot, with a high near 100. Heat index values as high as 108. South wind between 5 and 15 mph.

Friday Night: Partly cloudy, with a low around 80. South wind between 5 and 15 mph.

Saturday: Mostly sunny and hot, with a high near 100. Heat index values as high as 105. South wind between 5 and 10 mph.

Saturday Night: Partly cloudy, with a low around 78. South wind between 5 and 10 mph.

Sunday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny and hot, with a high near 100.

Sunday Night: A 20 percent chance of showers and thunderstorms before 10pm. Partly cloudy, with a low around 78.

Monday: Mostly sunny and hot, with a high near 99.

Monday Night: Partly cloudy, with a low around 78.

Tuesday: Mostly sunny and hot, with a high near 99.

Tuesday Night: Partly cloudy, with a low around 78.

Wednesday: Mostly sunny and hot, with a high near 100.

Wednesday Night: Partly cloudy, with a low around 78.

Thursday: Sunny and hot, with a high near 100.

Geez, that ridge better break down soon or Texas will turn into America's Sahara.
Member Since: July 7, 2010 Posts: 0 Comments: 5618
Quoting Tazmanian:




DSHP and SHIP takes 93L under a RI


Up to a strong Cat. 2 by Tuesday.
Member Since: October 8, 2008 Posts: 14 Comments: 4553
Quoting WeatherNerdPR:

The moment they've been waiting for...is almost here


Not so much in Houston:


Tonight: Partly cloudy, with a low around 80. South wind between 5 and 10 mph.

Friday: Mostly sunny and hot, with a high near 100. Heat index values as high as 108. South wind between 5 and 15 mph.

Friday Night: Partly cloudy, with a low around 80. South wind between 5 and 15 mph.

Saturday: Mostly sunny and hot, with a high near 100. Heat index values as high as 105. South wind between 5 and 10 mph.

Saturday Night: Partly cloudy, with a low around 78. South wind between 5 and 10 mph.

Sunday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny and hot, with a high near 100.

Sunday Night: A 20 percent chance of showers and thunderstorms before 10pm. Partly cloudy, with a low around 78.

Monday: Mostly sunny and hot, with a high near 99.

Monday Night: Partly cloudy, with a low around 78.

Tuesday: Mostly sunny and hot, with a high near 99.

Tuesday Night: Partly cloudy, with a low around 78.

Wednesday: Mostly sunny and hot, with a high near 100.

Wednesday Night: Partly cloudy, with a low around 78.

Thursday: Sunny and hot, with a high near 100.
Member Since: August 26, 2006 Posts: 16 Comments: 4766
Quoting TropicalAnalystwx13:
The Texas ridge is getting soft.



Well, that's more convection than Don could provide.
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910. MTWX
Well got to go install some parts, BBL.
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Quoting angiest:


Better Mexican food in Houston and San Antonio, I'd bet. ;)


angiest, I worked on the east side of Houston for 7 years, and I enjoyed the Mexican food, also miss a place called Burger-Tex. Also good Bar-B-Que places.
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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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