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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Quoting TampaMishy:
Hi Spin! I guess in a few days we will know about 97L.


Hi Neighbor.....nothing to worry about 97L Yet .......maybe if it makes it into the Caribbean ......we should start looking...if it goes north at all its Poof....South it might have a chance...
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Quoting KYhomeboy:


FIU??


Yep. Florida International, baby
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I don't think the x invest will really help the wave that dispersed just now but to use that moisture for its own.
Member Since: May 16, 2009 Posts: 0 Comments: 684
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Quoting BurnedAfterPosting:


Again I disagree with you, I hope you can accept that someone doesnt agree with you, but from what I have seen you get very defensive when someone disagrees with you.

It is ok to have different opinions


No thats ok....i just try to stress my point as i did the other nite....when most was saying that Ana was forming in 24hrs....
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yea I only see maybe 10 knots of shear in the area of the former 97L
Quoting KEEPEROFTHEGATE:
taz

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ace

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canesrule1

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I got an email from Ace confirming what we all knew.
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1340. DDR
Its going to be another wet day for the windwards ;D
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Quoting TampaSpin:
Look at this loop......it is very clear that out of the Shear has increased over 97L out of the NW.....LOOK!

Gang i don't just make things up....LOL!


Again I disagree with you, I hope you can accept that someone doesnt agree with you, but from what I have seen you get very defensive when someone disagrees with you.

It is ok to have different opinions
Quoting boiredfish:
Oops....about 1/4" here in Shoreacres today. Need more but not all at one time. Ditches still haven't been cleared well since Ike. Back in April we had two big rains that flooded houses that were just getting finished being repaired from Ike. Still lots of demo of houses going on; some really slow contractors, mostly out of state. Some seem to be more worried about filing liens than actually doing the work they contracted to do.


Hey im in la porte
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Quoting BurnedAfterPosting:
I agree SJ, that convection has nothing to do with shear


Maybe some 10knt shear assisting the perimeters, but it is in a pretty good environment right now minus the dry air...Which is a lot less then last night.
Member Since: August 17, 2005 Posts: 26 Comments: 15697
Quoting Patrap:
Im going to watch SNL,..a real rerun I presume.


Batten down for Sunday....

No swirlies to report this Evening.

Cookies and Milk are calling.


later PAT.. enjoy your weekend rerun!
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Look at this loop......it is very clear that out of the Shear has increased over 97L out of the NW.....LOOK!

Gang i don't just make things up....LOL!
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Hi Spin! I guess in a few days we will know about 97L.
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1333. Patrap
Im going to watch SNL,..a real rerun I presume.


Batten down for Sunday....

No swirlies to report this Evening.

Cookies and Milk are calling.


Member Since: July 3, 2005 Posts: 421 Comments: 127628
Quoting BurnedAfterPosting:


Again I disagree, I dont see shear causing that convection. The shear caused all of the convection with the wave at 60W, but not with this system.



I agree with ya.. the clouds don't look sheared either... with the antilles mess you could obviously see the stuff was sheared but this, no...
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I agree SJ, that convection has nothing to do with shear
Quoting TampaSpin:


The last 4-5 hours added shear has hit it..causing the added uplift.....its very visible to see!

The updated map is coming out soon we will se then
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Quoting TampaSpin:


The last 4-5 hours added shear has hit it..causing the added uplift.....its very visible to see!


Again I disagree, I dont see shear causing that convection. The shear caused all of the convection with the wave at 60W, but not with this system.

Evening TS

Not sure about that shear...Been decreasing pretty rapidly right in front of the wave and it seems to be pretty light S of 20N. for a good stretch.
Member Since: August 17, 2005 Posts: 26 Comments: 15697
Quoting weatherwatcher12:

There is 5 knots of shear over it


The last 4-5 hours added shear has hit it..causing the added uplift.....its very visible to see!
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Quoting TampaSpin:


Gang the added convection has increased because of Shear....Shear has caused an uplift and causing the added convection.....its about to enter the hostile territory that i have been addressing.....its time is very short now.

Time to say goodbye................sad music plays(Varsouviana music).........................................P.........O........O.........F.....!
Member Since: May 16, 2009 Posts: 0 Comments: 684
1325. beell
The "60" wave-or at least a part of it.

Photobucket

SSD IR Loop
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Quoting TampaSpin:


Gang the added convection has increased because of Shear....Shear has caused an uplift and causing the added convection.....its about to enter the hostile territory that i have been addressing.....its time is very short now.


I highly disagree, you can clearly see where the shear is, this system is not at that point and with shear decreasing it wont get affected as much by the shear

of course I know you just cant wait to tell everyone "I told you so"
Quoting TampaSpin:


Gang the added convection has increased because of Shear....Shear has caused an uplift and causing the added convection.....its about to enter the hostile territory that i have been addressing.....its time is very short now.

There is 5 knots of shear over it
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Click image for full image.

The convection is associated with the area in the box from what I can tell...This pass is a few ours old now, but it shows a couple random NNW and WNW barbs in some places...If you look real close.
Member Since: August 17, 2005 Posts: 26 Comments: 15697
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Quoting JLPR:
impressive if this keeps up ex 97L could become 97L again =P

looks like the moisture left behind by the TW in front of it helped it and now it is developing convection, if it manages to recuperate its circulation we might have something here


Gang the added convection has increased because of Shear....Shear has caused an uplift and causing the added convection.....its about to enter the hostile territory that i have been addressing.....its time is very short now.
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still dont see any cyclonic turning anymore
1318. JLPR
impressive if this keeps up ex 97L could become 97L again =P

looks like the moisture left behind by the TW in front of it helped it and now it is developing convection, if it manages to recuperate its circulation we might have something here
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1317. Patrap
No Invest at this time on the NOAA Floaters

Zilch,nada,nary a ting.

AL972009 was deactivated this afternoon.

Atlantic and Caribbean Tropical Satellite Imagery
Member Since: July 3, 2005 Posts: 421 Comments: 127628
1316. KEEPEROFTHEGATE (Mod)


still some dry air around
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Im starting to get a sore eye for invests,blobs,tropical depressions.Seeing a very classical hurricane with a perfect eye has become a dry dream for me now because there hasn't been one here for a long time.
Member Since: May 16, 2009 Posts: 0 Comments: 684
Quoting BurnedAfterPosting:
While convection has increased with the former 97L, I do not see any cyclonic turning anymore


I think there def. is some but it's in the lower levels so its harder to see. Use the crazy old rainbow loop which exaggerates the colors and you can see it better.
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1309

Be careful keeper. You are the gatekeeper here, you may be revoked if you keep this up. lol
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1311. Patrap

Central Atlantic - Rainbow Color Infrared Loop

Member Since: July 3, 2005 Posts: 421 Comments: 127628
"ex-97l"?
You mean they dropped it as an invest?
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1309. KEEPEROFTHEGATE (Mod)
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hey everyone been gone since 2pm @ work and just got home so what is/has been going on with our invest and the wave that was at/near 60W? can someone give me a quick update and summary please?
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Looks like some dry air wedged in to x97...



Any thoughts on the impact to x97 of that leftover moisture in front of it?
Member Since: August 17, 2005 Posts: 26 Comments: 15697
While convection has increased with the former 97L, I do not see any cyclonic turning anymore
1305. Patrap


Central Atlantic - RGB Color Infrared Loop
Member Since: July 3, 2005 Posts: 421 Comments: 127628
Quoting StormJunkie:


I was on the 60w bandwagon earlier Drak...Guess I was wrong there...lol... Also did not think 97l would give it a go tonight.



I was having doubts, because I focused on the 50w wave, since I knew that the wave near the Antilles did not have a chance anytime soon. Then NHC decided to drop the invest, and that is why I stopped posting for most of the afternoon.

LOL I thought my expectations were wrong.
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1303. KEEPEROFTHEGATE (Mod)
taz

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ace

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canesrule1

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Ex-97L

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Quoting FloridaTigers:
Fun fact: Where I work, NHC NOAA meteorologists always stop by. They use the university's gym, and its only about 700 yards from the NHC itself.

Maybe I should ask them hard hitting questions like "wheres it gonna hit".


FIU??
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1300. CUBWF
Good evening everyone. Looks ex-97 has better circlation tonight with encrease of convections. Let see if it's capable of keep it for at least 18 hours continued.
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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.