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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Quoting aquak9:

hiking, sight-seeing, eating awesome mexican food, drinking fancy california wines...it's a rough life.


I'd gladly take the first three of those any day (:
Member Since: October 8, 2008 Posts: 14 Comments: 4553
Who wants my weather? Speak now, or forever keep your bad weather.

Member Since: July 6, 2010 Posts: 113 Comments: 31898
857. SLU
140N, 373W suggests that 92L is very disorganised. 93L has a much better chance at being named Franklin.
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Quoting JFV2013:
im really hoping that 93l hits the conus, but we'll see.


If it would only stay a tropical storm, and go to Texas? that would be the answer to many prayers.
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Quoting clwstmchasr:
Bad news for Texas with the heatwave continuing, means good news for us in the Eastern GOM. That high will block any storms from getting into the GOM.


For now anyways.
Member Since: July 6, 2010 Posts: 113 Comments: 31898
Quoting aquak9:

hiking, sight-seeing, eating awesome mexican food, drinking fancy california wines...it's a rough life.


Better Mexican food in Houston and San Antonio, I'd bet. ;)
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Quoting bigwes6844:
how much would it take to get it to a depression mbs im saying


There is no pressure requirement for TD/TS status.
Member Since: July 15, 2006 Posts: 17 Comments: 10209
Quoting Tazmanian:
too me it looks like 92L has turn in too a open wave

Looks pretty Bad right now...
Member Since: October 24, 2005 Posts: 0 Comments: 24245
Quoting floodzonenc:
So what does a met in San Diego do with the other 23 hours and 55 minutes of his or her day?  :)



lol...same as here..HOT..100 DEGREES no chance of rain for the next year
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Quoting stormwatcherCI:
Are they not running this for 93L ?



they are this takes time
Member Since: May 21, 2006 Posts: 5091 Comments: 114954
Quoting floodzonenc:
So what does a met in San Diego do with the other 23 hours and 55 minutes of his or her day?  :)


hiking, sight-seeing, eating awesome mexican food, drinking fancy california wines...it's a rough life.
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Quoting Neapolitan:
Pressure up just a bit:

AL, 92, 2011081200, , BEST, 0, 140N, 373W, 25, 1011, LO, 34, NEQ, 0, 0, 0, 0, 1014, 200, 90, 0, 0, L, 0, , 0, 0, INVEST, S,
Are they not running this for 93L ?
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843. MTWX
Quoting Neapolitan:

Big Timber (beautiful), then Hardin (not so much). ;-)

LOL! I Lived in Great Falls for 10 years. I sure do miss it!
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Quoting Neapolitan:
Pressure up just a bit:

AL, 92, 2011081200, , BEST, 0, 140N, 373W, 25, 1011, LO, 34, NEQ, 0, 0, 0, 0, 1014, 200, 90, 0, 0, L, 0, , 0, 0, INVEST, S,
how much would it take to get it to a depression mbs im saying
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in florida btw...sorry.
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92L has relly weakin tonight
Member Since: May 21, 2006 Posts: 5091 Comments: 114954
Quoting MTWX:
Quoting Neapolitan:

You have to get out more if you want to see the heavy weather. ;-) I do move around a lot: born in California; Iowa; Missouri; Alabama; back to California; Wyoming; Montana; back to Wyoming; Minnesota; Florida; Texas; Ohio; back to Florida; Colorado; back to Florida, back to California; back to Florida; back to California; and, now, back to Florida. Whew... ;-)


Where at in MT were you Neo?


Big Timber (beautiful), then Hardin (not so much). ;-)
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weird, backwards flow has stopped tonight and storms are barrelling thru as if high pressure is steering. WTF? I thought we were to continue with this off the water flow, not this.
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Ah, geek(ier) night on the blog I see.

;)
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Pressure up just a bit:

AL, 92, 2011081200, , BEST, 0, 140N, 373W, 25, 1011, LO, 34, NEQ, 0, 0, 0, 0, 1014, 200, 90, 0, 0, L, 0, , 0, 0, INVEST, S,
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833. SLU
395

WHXX01 KWBC 120048

CHGHUR

TROPICAL CYCLONE GUIDANCE MESSAGE

NWS NATIONAL HURRICANE CENTER MIAMI FL

0048 UTC FRI AUG 12 2011



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 (AL922011) 20110812 0000 UTC



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

110812 0000 110812 1200 110813 0000 110813 1200



LAT LON LAT LON LAT LON LAT LON

BAMS 14.0N 37.3W 14.9N 40.3W 16.0N 43.7W 17.2N 47.7W

BAMD 14.0N 37.3W 14.8N 40.6W 15.7N 44.1W 16.6N 47.6W

BAMM 14.0N 37.3W 14.9N 40.3W 16.0N 43.9W 17.1N 47.7W

LBAR 14.0N 37.3W 14.9N 40.5W 15.9N 44.1W 16.7N 48.0W

SHIP 25KTS 29KTS 35KTS 43KTS

DSHP 25KTS 29KTS 35KTS 43KTS



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

110814 0000 110815 0000 110816 0000 110817 0000



LAT LON LAT LON LAT LON LAT LON

BAMS 18.9N 51.7W 23.0N 59.4W 27.5N 65.2W 33.4N 66.1W

BAMD 17.5N 50.9W 19.3N 56.5W 20.8N 61.0W 21.9N 65.4W

BAMM 18.5N 51.4W 21.5N 58.1W 24.9N 63.7W 29.0N 67.7W

LBAR 17.7N 51.8W 19.8N 58.2W 21.9N 62.6W .0N .0W

SHIP 51KTS 57KTS 57KTS 59KTS

DSHP 51KTS 57KTS 57KTS 59KTS



...INITIAL CONDITIONS...

LATCUR = 14.0N LONCUR = 37.3W DIRCUR = 285DEG SPDCUR = 14KT

LATM12 = 13.3N LONM12 = 34.5W DIRM12 = 285DEG SPDM12 = 14KT

LATM24 = 12.7N LONM24 = 32.0W

WNDCUR = 25KT RMAXWD = 90NM WNDM12 = 25KT

CENPRS = 1011MB OUTPRS = 1014MB OUTRAD = 200NM SDEPTH = S

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



$$

NNNN
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too me it looks like 92L has turn in too a open wave
Member Since: May 21, 2006 Posts: 5091 Comments: 114954
831. MTWX
Some places in TX getting upwards of an inch of rain! I know its's not much but at least it knocks the dust down...

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Quoting TomTaylor:
One last thing before I go, here's the NWS forecast for my location in San Diego, California



Cloudy all day and night. Light to calm winds. Highs in the low 70s, lows in the low 60s. Repeat for the next week. Going outside right now to go swimming in cool, cloudy weather.

Anyway, later all


I'm tempted to minus this post...jk
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Is the Gfs really serious and tryna take this thing into the Carribean and the GFDL
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Fellow Texans...things just changed!

http://www.atmos.washington.edu/~ovens/loops/wxlo op.cgi?wv_east_enhanced+12

Frames 9-12 show a lotta new precip spinning towards centex.

(In TX it rarely rains after sundown so this is a novelty)
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Quoting TomTaylor:
One last thing before I go, here's the NWS forecast for my location in San Diego, California



Cloudy all day and night. Light to calm winds. Highs in the low 70s, lows in the low 60s. Repeat for the next week. Going outside right now to go swimming in cool, cloudy weather.

Anyway, later all


Oh, I'd love to be there LOL
Member Since: October 8, 2008 Posts: 14 Comments: 4553
Quoting JFV2013:
Guys, today is my birthday, does no one care? =(/


Happy birthday! I hope you had a great one.
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Quoting TomTaylor:
One last thing before I go, here's the NWS forecast for my location in San Diego, California



Cloudy all day and night. Light to calm winds. Highs in the low 70s, lows in the low 60s. Repeat for the next week. Going outside right now to go swimming in cool, cloudy weather


I hate you. LOL.
Member Since: July 15, 2006 Posts: 17 Comments: 10209
One last thing before I go, here's the NWS forecast for my location in San Diego, California



Cloudy all day and night. Light to calm winds. Highs in the low 70s, lows in the low 60s. Repeat for the next week. Going outside right now to go swimming in cool, cloudy weather.

Anyway, later all
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821. MTWX
Quoting Jedkins01:





You couldn't pay me to use Linux, I would rather do Calc 2 any day than learn how to use Linux.

It's not too bad. I got kind forced into it at work. NEXRADs run on it, as do our other radar systems.
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Quoting Levi32:


This is true, especially if you are an experimental critter, but I have managed to get my distribution pretty rock-solid stable. If you're not playing with new kernels, servers, or massive clusters it's not too hard to keep it tame.


What's the fun without building custom kernels?
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818. xcool
MississippiWx haha
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Quoting robj144:


Linux can be a real pain though sometimes. I manage our Linux network in my department, and some really strange problems crop up all the time that take days to fix.





You couldn't pay me to use Linux, I would rather do Calc 2 any day than learn how to use Linux.
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Quoting xcool:
JFV2013 that not nice call someone white-tailor trash


Lol...I didn't know tailors were trash either.
Member Since: July 15, 2006 Posts: 17 Comments: 10209
815. xcool
JFV2013 that not nice call someone white-tailor trash
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Quoting JFV2013:


How could you say something like that, you sir are an absolute heartless monster at an atrocious level. You white-tailor trash, how would you like it if someone said that to you on your birthday?


Need I say anything else about wishing happy birthday to him/her/it?

Poof.
Member Since: July 15, 2006 Posts: 17 Comments: 10209
812. GoWVU
Do not like the look of the picture on #808 that is in my back yard!! Been there done that= NO FUN!!
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811. MTWX
Quoting Neapolitan:

You have to get out more if you want to see the heavy weather. ;-) I do move around a lot: born in California; Iowa; Missouri; Alabama; back to California; Wyoming; Montana; back to Wyoming; Minnesota; Florida; Texas; Ohio; back to Florida; Colorado; back to Florida, back to California; back to Florida; back to California; and, now, back to Florida. Whew... ;-)


Where at in MT were you Neo?

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Quoting Neapolitan:

You have to get out more if you want to see the heavy weather. ;-) I do move around a lot: born in California; Iowa; Missouri; Alabama; back to California; Wyoming; Montana; back to Wyoming; Minnesota; Florida; Texas; Ohio; back to Florida; Colorado; back to Florida, back to California; back to Florida; back to California; and, now, back to Florida. Whew... ;-)


Dang man. You've been all over the place. Or at least all over the United States.

Anyway, I think I'll take your advice about getting out more and get my butt off the ol' seat in front of the monitor. I was just gonna stop by for a little, turned out to be in front of the computer for the last three hours lol

Out for now, see you all later tonight
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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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