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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Thanks SJ!

I was probably seeing something else.. I don't think there is any "swirl" to the wave yet either.

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The 60w wave is not an invest at this point Ace.
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Guys, dont be fooled. That convection was caused because of the combination of the wave itself and the TUTT. The coulds appear to be faning out because they are being sheared. That moisture will remain away from the center of the invest and maybe become absorbed by ex 97L. Look at the most recent visible and ir loops and you will see convection increasing where it should be in order for this to develop. Also, look at ex 97L...the lower level cloud deck appears to be re-organizing from the mess it was earlier on today. I would not be too quick to throw this one out of the window
546. beell
Pretty big jog to the N for the ITCZ.

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SAT JUL 18 2009

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 10N14W 9N29W 10N34W 11N42W 8N46W
13N60W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM OF A LINE
FROM 10N12W TO 6N24W. SIMILAR CONVECTION IS FROM 6N-9N BETWEEN
47W-52W.
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Lets remember how many on here were shouting at the NHC when Dolores was classified a 40mph TS

They would look at Carlos and look at Dolores and think the NHC was nuts for thinking Carlos was a hurricane and Dolores was only a 40mph TS

Moral is in the tropics a picture does not tell the whole story.
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Quoting AllStar17:
Ex-97 L already flaring up a bit as it moves into a more conducive environment

Lol it flares up after they deactivate.
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Hey Gamma, good to see you. Mike's doing great! Thanks for asking.

isn't the "naked" circulation out in front of all the clouds?

I don't know where the circulation or wind shift is. I don't think it is way out in front of the 60w wave though...Hard to tell with the associated convection though...
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Shear decreasing by 30knots over the SOCAR.

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Quoting WxLogic:
Based on the 18Z Shear Maps shear has been subsiding in the S and now Central Carib Sea... with some indications of an Upper Level High starting to build in the Eastern Carib Sea... if the new INVEST is able get underneath it... then things might shape up rather quickly.


Thanks for that input. something to think about.. guess if it survives this current shear it could get it together..

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Ex-97 L already flaring up a bit as it moves into a more conducive environment
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Quoting Acemmett90:
bap
there is a reason they made it an invest even while the convection is waning


Its not an official invest
. They just put a floater on it.
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Quoting Acemmett90:

its spreading out thats why


No, its waning. And typically when disturbances wane, they usually spread out.

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97L has a shot, but its looking bleak.
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Quoting StormJunkie:


Ex97 and the 60W wave...


97L looks to be bubbling up a bit of deep convection by looking at that IR, we'll see...
Member Since: July 1, 2008 Posts: 13 Comments: 7396
Based on the 18Z Shear Maps shear has been subsiding in the S and now Central Carib Sea... with some indications of an Upper Level High starting to build in the Eastern Carib Sea... if the new INVEST is able get underneath it... then things might shape up rather quickly.
Member Since: August 14, 2008 Posts: 4 Comments: 4978
Quoting Stormchaser2007:
Cirrus increasing. Convection is waning and it isn't likely due to the diurnal minimum.



Those thunderstorms are enhanced by the TUTT. Do not bother with that wave, watch Ex-97L, as I have a feeling this one is not done yet.
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Hey SJ! How you doing and your handsome son?


Isn't that "wave" getting blown by shear?

isn't the "naked" circulation out in front of all the clouds? Just wondering.
That doesn't sound too healthy to me.
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Quoting Stormchaser2007:
Cirrus increasing. Convection is waning and it isn't likely due to the diurnal minimum.



yup that is what I am seeing, expect a rapid decrease in convection over the next few hours

Hope that doesnt disappoint too many in here lol
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Quoting StormJunkie:


Ex97 and the 60W wave...


IMO, if the thunderstorms continue to dissipare with the wave at 60 W, Ex-97L would fare better.
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Cirrus increasing. Convection is waning and it isn't likely due to the diurnal minimum.

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Quoting BurnedAfterPosting:


It always takes the navy site awhile to take things down

I mean take a look they still have Dolores up lmao


NHC has not deactivated Dolores, although they have stopped issuing advisories, they are still tracking the remnant low.
Member Since: September 23, 2005 Posts: 14 Comments: 11223


Ex97 and the 60W wave...
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Just because 97L is gone in number/invest, does not mean it still does not need to be watched. It will be moving into a more favorable environment tonight and tomorrow near the Lesser Antilles "sweet spot". Look for a large flare-up, and at which time this system could pull back together.
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Here it comes
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Link

Visible loop shows some organizing in the lower levels. Convection appears to be on the increase.

97L is offically dead...though I think this might be temporary.
Quoting SLU:


Don't worry ... she will be back


doubt it, but we will see
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Good afternoon everyone,

been lurking when I can and I must take exception to a few of the "south Florida wishcasters"....

2004 and 2005 wERE enough... some damage from the 2004 storms, some from Katrina & Rita...but
Wilma sucker punched us badly and while my home and family wERE very prepared and came thru just fine...my landscaping and garden and fence didn't. $10,000 later, from our own pocket to take care of things the insurance didn't cover.
ACTUALLY our insurance didn't cover anything that was damaged.

plus all the hard work bringing everything inside, etc.

Forget about it; we do not want storms like that every few years....once a decade or once every 15-20 years would be plenty to keep everyone on their toes..


just my opinon..

I declare NO Storms for the CONUS this year!


That is "WRITTEN IN STONE" rofl!!
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519. SLU
Quoting nrtiwlnvragn:
invest_DEACTIVATE_al972009.ren


Don't worry ... she will be back
Member Since: July 13, 2006 Posts: 13 Comments: 5282
And they had Carlos up for awhile after it dissipated.
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Quoting weatherwatcher12:
The Invest is still active on the navy site. Should this be happening?


It always takes the navy site awhile to take things down

I mean take a look they still have Dolores up lmao
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Quoting weatherwatcher12:
The Invest is still active on the navy site. Should this be happening?


It usually takes a few hours for them to remove it.
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If the 60W INVEST is able to remove itself further from the TUTT to its N and able to keep its current convection and fight off the shear for the next 24 to 48 hours it might have a chance. DMIN should be there soon so will be interesting to see if the convection persists until DMAX arrives and may be tomorrow it might get a numerical designation.
Member Since: August 14, 2008 Posts: 4 Comments: 4978
Quoting BurnedAfterPosting:


you have your own opinion and that is fine, but in terms of deactivating an invest, I will go with the professionals


Apparently there thinking it will get sucked into the blob up there, which is certainly possible. I think that's the reason why it was scrubbed. It actually looks better then last night and even this morning.
Member Since: July 1, 2008 Posts: 13 Comments: 7396
The Invest is still active on the navy site. Should this be happening?
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Quoting reedzone:


I personally think there making a wrong decision. I see convection starting to get a bit more organized with a new center right under it, you can also see the banding has gotten a tad better. I'm not writing it off yet.


you have your own opinion and that is fine, but in terms of deactivating an invest, I will go with the professionals
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Quoting BurnedAfterPosting:


kinda funny that you posted this when you did, right before the deactivate 97L was shown lol

Its dead now lol


I personally think there making a wrong decision. I see convection starting to get a bit more organized with a new center right under it, you can also see the banding has gotten a tad better. I'm not writing it off yet.
Member Since: July 1, 2008 Posts: 13 Comments: 7396
either that or maybe they finally woke up and thought "wait a minute, this should have been 95L", so they deactivated 97L to rename it 95L lmao
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We will miss you 97. You have provided chills and thrills...and a few banishments. You will always be remembered...until we have 98L.
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Quoting sporteguy03:


Hi Stormjunkie,
Maybe NOAA thinks the wave out in front might have better advantage of Caribbean lower shear?


After looking at the models, several of them seem to show that area carrying a lower level of shear with it...Almost like a weak anti cyclone, but now I am way out of my league.
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Nice cells over NOFL.
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504. beell
I think the western wave is still on the move along 62W. You can watch its progress as it interacts with a very small ULL centered near 22N 57W.
SSD WV
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helloo everyone,in my opinion, i think The NHC wants to focus more on the wave near the antilles simply because is closer land and that is why they change floater. Probably we can see a new invest out of this wave and probably not
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Quoting reedzone:
Structure is still impressive and THERE IS convection on 97L, but not deep convection, that might happen late tonight though. Shear took a drastic drop in the Carribean to 5 knots in some areas. This is good for 97L. I definitely see a new spin with convection with 97L, it's not done yet folks, I think this is starting to get into a moist environment and it's actually looking good right now. Look for a circulation near and around 47W and 11N

http://rammb.cira.colostate.edu/ramsdis/online/latest_image_640.asp?product=tropical_ge_4km_ir4_flo ater_1


kinda funny that you posted this when you did, right after the deactivate 97L was shown lol

Its dead now lol
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500. Skyepony (Mod)
The new invest is a NOAA declared invest, Navy should name it soon or waiting for 97L to get tangled in it. They don't always agree. Usually don't see waves combine. That one at 60 looks like it has hit a wall while 97L Keeps treking fast. Interesting is the N edge bit of the 60W blob convection..maybe ULL about to form there just W of there
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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.