Two African waves worth mentioning

By: Dr. Jeff Masters , 3:51 PM GMT on July 18, 2009

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There are two African tropical waves worth mentioning today, though neither looks particularly threatening. A tropical wave near 12N 45W, about 1200 miles east of the Lesser Antilles Islands (97 L), is moving west at 15 - 20 mph. This wave is now surrounded by an area of very dry air from the Sahara Desert. The dry air has disrupted most of the wave's heavy thunderstorm activity, and will continue to make it difficult for this system to develop over the next 2 - 3 days. Wind shear is a modest 10 knots over the disturbance, and should remain in the moderate 10 - 15 knot range over the next 2 - 3 days. Thereafter, shear is expected to rise to 20 - 30 knots. This morning's QuikSCAT pass showed no evidence of a surface circulation, and only a modest wind shift associated with 97L. The National Hurricane Center is giving this system a low (less than 30% chance) of developing into a tropical depression in the next 48 hours.

A second tropical wave now approaching the northern Lesser Antilles Islands is under 30 knots of wind shear, and has little prospect of development due to the high shear. However, the wave will bring heavy rain to the islands over the next two days.

None of the computer models are forecasting tropical storm development over the next seven days, and I don't expect either of the two African waves mentioned today to develop over at least the next three days.


Figure 1. Current satellite image of African wave 97L, 1200 miles east of the Lesser Antilles Islands.

I'll have an update Sunday afternoon.
Jeff Masters

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I know this will sound dumb, and it probably is, but if 97L catches up with the tropical wave as I see it, the wave has the convection and 97L has the possible developing LLC, so all 97L needs is the convection and lower shear to get going, but because of larger area of convection the wave will get the creadit if anything is spawned when actually it was 97L that really got things going, Oh well, just a thought on a hot Saturday afternoon, probably frying my brain as well.
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441...

Not pointing out things that I think are "wrong" just things I view differently...Which should lead to discussion/debate with folks that have a different point of view..desired out come...We learn.
Member Since: August 17, 2005 Posts: 26 Comments: 15891
Ont se fait copieusement arrosé par cette onde dans les Antilles et ca devrais durer encore un moment



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Quoting FloridaTigers:


Or is that what YOU want to happen?
i took that off, and no i dont want that to happen ill be happy with a Wave.
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Quoting Patrap:
2009 Atlantic Cane Season



Yea, but when you get it going it does when you least expect it. Well for me atleast.
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Quoting canesrule1:
new track forecast for the blob: i think this blob is going to stay a blob and move into S-FL, i think it will be a low pressure area moving into S-FL next week, if I'm wrong ill eat my crow don't think we are going to have TD#2 out of this.


dont forget about 97L ;)
when the antilles blob was in the same spot 97L was it looked even worse. I wonder what 97L will do when it gets to the antilles...
Member Since: July 7, 2008 Posts: 2 Comments: 3237
I think you have to look at future conditions in the areas where these two systems are going

The wave at 60W, now it may look all pretty and stuff on satellite, but that convection was created due to interaction with the TUTT, for something tropical to form, the convection has to be self-sustaining; which is not the case. Add to that the fact that this wave will be moving north of the Islands based on forecasts and will stay in an area of higher wind shear; development is not likely

Now 97L, yes it doesnt look as "pretty" on satellite, but in hindsight if you look it has a better structure still than the wave at 60W. Also it is moving into a much more favorable environment than the wave at 60W will be moving. As 97L gets to the Caribbean, shear will be favorable and the environment will be more moist with no SAL.


You have to look at the situation as a whole, if you do you will realize that 97L still has the best shot to develop.
new track forecast for the blob: i think this blob is going to stay a blob and move into S-FL, i think it will be a low pressure area moving into S-FL next week, if I'm wrong ill eat my crow don't think we are going to have TD#2 out of this.
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Quoting StormJunkie:
then its 100%

There is rarely ever 100% anything when dealing with the tropics...That said, 97l is on life support at the moment.


i estimate :P

btw do you read everyone's posts just to find one little thing wrong with it and then point it out?
Member Since: July 7, 2008 Posts: 2 Comments: 3237
Quoting canesrule1:
what i think will happen with the blob is Hurricane Ana making landfall in S-FL, imo. Thoughts?


Or is that what YOU want to happen?
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Quoting canesrule1:
yeah thats not looking good now im kind of skeptical, think we are all done for now, i think we got hyped all over nothing. damn.


LOL. Well if your desperate enough you can do this

http://www.stevespanglerscience.com/experiment/00000122

:P

imo, if 97L makes a come back in the "sweet spot" and enters the caribbean then we just might have something to track.. but its not likely
Member Since: July 7, 2008 Posts: 2 Comments: 3237
then its 100%

There is rarely ever 100% anything when dealing with the tropics...That said, 97l is on life support at the moment.
Member Since: August 17, 2005 Posts: 26 Comments: 15891
Quoting Patrap:
2009 Atlantic Cane Season

lol, very true!
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Quoting HurricaneSwirl:


its been that strength ever since it got declared an invest


I know that. Just saying that its one of the weaker invests i've seen.
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ok well nevermind then, I am tired of debating

lol BAP...That's what it is all about though. If there is data there to back up a point of view then it is worth discussion. Provide links and relevant data and I will concede any point proven. I'm here to learn, share, and occasional help others learn...if I can.

And maybe I should have said I think 97 is done for now. 3-5 days from now...Who knows? That's just a crap shoot. I do think it will have a hard time keeping it's signature that long.

I have been wrong many times before and will surely be wrong again :~)
Member Since: August 17, 2005 Posts: 26 Comments: 15891
looking at recent vis sat pics . it appears that anoter LLC is trying to form beneath the heaviest ball of convection near 15n 57w. low level clouds are streaming to that location
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2009 Atlantic Cane Season

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Quoting HurricaneSwirl:


The shear is lifting out of the caribbean and into south florida and the bahamas.. imho theres no chance.
yeah thats not looking good now im kind of skeptical, think we are all done for now, i think we got hyped all over nothing. damn.
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Quoting canesrule1:
dont rip it just yet wait till tomorrow, then you rip it all you want


yeah i agree, if it cant get its act together tomorrow when its in a sweet spot with moist environment and higher SST's then its 100% RIP.
Member Since: July 7, 2008 Posts: 2 Comments: 3237
This blog will never learn. I give up. Although, 97L is pretty sickly right now and is getting close to being pretty much dead, Im not writing it off just yet. I've been slapped across the face when I wrote off systems last year by a Category 2, a Category 4, and a 4 time landfalling TS/Category 1.
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429. IKE
Quoting CUBWF:
Will the T-Storms in the GOM has any chance to get down to SFlorida


Miami,FL. afternoon discussion....

"THE HIGH WILL REMAIN NEARLY STATIONARY OVER THE SOUTHERN AREAS OF
THE CWA ON SUNDAY....AS A WEAK FRONTAL BOUNDARY OVER NORTH FLORIDA
CONTINUES TO MOVE SLOWLY SOUTH INTO CENTRAL FLORIDA. THIS WILL
KEEP THE STEERING FLOW FROM THE SOUTH TO SOUTHWEST DIRECTION...AND
ALLOW FOR TROPICAL MOISTURE TO WORK INTO THE CWA FROM THE GULF OF
MEXICO. THE HAZY CONDITIONS OVER THE SOUTHERN AREAS OF THE CWA
SHOULD ALSO BE GONE BY SUNDAY AFTERNOON ALLOWING FOR MORE SHOWER
AND THUNDERSTORM DEVELOP OVER THE SOUTHERN AREAS. SO HAVE INCREASE
THE POPS TO CHANCE CAT OVER ALL OF THE CWA WITH THE HIGHEST POPS
AGAIN OVER THE NORTHEAST AREAS OF SOUTH FLORIDA.

THE FRONTAL BOUNDARY WILL THEN WASH OUT OVER CENTRAL FLORIDA ON
MONDAY AS THE HIGH WEAKENS OVER SOUTH FLORIDA. THIS WILL ALLOW FOR
THE STEERING FLOW TO BECOME LIGHT AND VARIABLE OVER THE CWA...AND
ALLOW FOR THE SEA BREEZES TO BE THE MAIN PLAYERS ON MONDAY. SO
HAVE KEPT THE CHANCE CAT POPS OVER THE AREA ON MONDAY.

HIGH TEMPS ON SUNDAY WILL AGAIN BE IN THE LOWER TO MID 90S OVER
MOST AREAS...WITH LOWS IN THE 70S EXCEPT AROUND 80 ALONG THE EAST
COAST METRO AREAS. THIS WILL MAKE THE HEAT INDICES ON SUNDAY TO BE
IN THE 105 TO 110 DEGREES RANGE OVER THE INTERIOR AREAS AND AROUND
105 OVER THE METRO AREAS.


.EXTENDED FORECAST...
THE TROPICAL WAVE OVER THE WINDWARD ISLAND WILL BE MOVING WEST TO
NORTHWEST THIS WEEKEND AND INTO SOUTH FLORIDA AREA ON TUESDAY INTO
MIDDLE OF NEXT WEEK. HOWEVER...THE LONG RANGE MODELS ALSO NOW SHOWS
THE TROUGH OF LOW PRESSURE OVER THE CENTRAL UNITED STATES TO BE
MOVING EAST INTO THE EASTERN UNITED STATES DURING MIDDLE OF NEXT
WEEK. IF THE LONG RANGE MODELS ARE CORRECT THEN THE MOISTURE WITH
THE TROPICAL WAVE WILL PASS EAST OF THE CWA WHILE MOVING
NORTHWARD WHICH COULD LOWER THE COVERAGE OF SHOWERS AND
THUNDERSTORMS OVER SOUTH FLORIDA. AT THIS TIME WILL NOT MAKE ANY
CHANGES TO THE EXTENDED FORECAST AND WAIT TO SEE IF LATER RUN IN
THE LONG RANGE MODELS KEEP THE TREND OR NOT. SO WILL CONTINUE TO
INDICATE SCATTERED POPS FOR THE CWA FOR THE MIDDLE TO END OF NEXT
WEEK.

FOR ANY POSSIBLE DEVELOPMENT ON THE TROPICAL WAVE...PLEASE SEE THE
NATIONAL HURRICANE TROPICAL OUTLOOK PRODUCT."
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting BurnedAfterPosting:
ok well nevermind then, I am tired of debating

RIP 97L, just deactivate it already
dont rip it just yet wait till tomorrow, then you rip it all you want
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Quoting HurricaneSwirl:


its been that strength ever since it got declared an invest
true it was going at 20 when declared and it was at 1012mb just increased 1 millibar, big deal.
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Quoting canesrule1:
what i think will happen with the blob is Hurricane Ana making landfall in S-FL, imo. Thoughts?


The shear is lifting out of the caribbean and into south florida and the bahamas.. imho theres no chance.
Member Since: July 7, 2008 Posts: 2 Comments: 3237
AL97 GOES-12 Low Cloud Product
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424. CUBWF
Will the T-Storms in the GOM has any chance to get down to SFlorida
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.
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ok well nevermind then, I am tired of debating

RIP 97L, just deactivate it already
Quoting Stormchaser2007:


LOL...23mph and 1013mb. Thats pretty dang close to dead.


its been that strength ever since it got declared an invest
Member Since: July 7, 2008 Posts: 2 Comments: 3237
good afternoon SLU

you are so correct with your analysis. i made that analyais a few hours ago just before 456 did his thing on futuremet post. st lucia was having west winds since 10. 30 am and i made that observation abd suggested that a surface low maybe forming
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Quoting stormpetrol:
Will 97L be absorbed by the wave near the lesser & windwards, it sure seems to be catching up.


97l is catching the convection being sheared off to the east of the 60w wave. Both waves are moving.

Honestly I think the 60w wave will form something near Florida (Either south of florida or east of florida) and then graze the east coast.

97L might be a close to home storm if anything is left. It might have a chance in the west caribbean or Gulf by the end of next week.
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Quoting nrtiwlnvragn:
AL 97 2009071818 BEST 0 123N 442W 20 1013 DB


LOL...23mph and 1013mb. Thats pretty dang close to dead.
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AL 97 2009071818 BEST 0 123N 442W 20 1013 DB
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latest enhanced wv image atl basin 303 pm edt
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Fountainbleau area
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Yes,..it shows well here

GOES-12 Channel 3 (WV)
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Quoting StormJunkie:


Well what I do know is that there is pretty much 0 model support for anything out of 97, while the GFS and CMC show the 60w wave either moving up the E coast, or into the W coast of S fla. The only thing I can find going for 97 is that it is a small system in low shear so with some added convection it could close off again.


and with how bad the models have been this year, that basically means squat

once 97L gets into the Caribbean it will find a more moist environment
Quoting stormpetrol:
Will 97L be absorbed by the wave near the lesser & windwards, it sure seems to be catching up.
yeah that im thinking we might have only one later tonight.
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Quoting Patrap:


Pat do you see that sudden breakthrough between 97L and the TUTT flareup?
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Quoting Patrap:
GOM Low Cloud Product


Northern Gulf of Mexico (Updated every ~10-15 mins.)


Uh, whats up with the funny looking clouds in that link by you Patrick? Is that the trough that was thought to split from conversation a few days ago?
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Quoting KC2NOLA:
Patrap-

Uptown here as well! 7th year in NOLA and I still love as much as the first.


Yeah ya right...
Were near Magazine and Jefferson

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Islands view.


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why is everyone ripping 97L its the invest here not the blob, keep that in mind, anyways if you look at the satellite imagery below it looks the best it has all day, imo...
Link
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Quoting BurnedAfterPosting:
97L is far from dead, dry air is being filtered out, these things take time

wave at 60W is clearly enhanced by the TUTT and is not self sustaining; you dont get developing systems in that scenerio

Guess we will see what happens


Well what I do know is that there is pretty much 0 model support for anything out of 97, while the GFS and CMC show the 60w wave either moving up the E coast, or into the W coast of S fla. The only thing I can find going for 97 is that it is a small system in low shear so with some added convection it could close off again.
Member Since: August 17, 2005 Posts: 26 Comments: 15891
405. IKE
Quoting CUBWF:
Hi Ike, long time seeing your post. Very useful for me. Nice finally meeting you.


Nice meeting you and welcome.
Member Since: June 9, 2005 Posts: 23 Comments: 37858
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Patrap-

Uptown here as well! 7th year in NOLA and I still love as much as the first.
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402. CUBWF
Hi Ike, long time seeing your post. Very useful for me. Nice finally meeting you.
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Will 97L be absorbed by the wave near the lesser & windwards, it sure seems to be catching up.
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Welcome aboard NOLA Homie,..Uptown Ruler here.
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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.