Rains From Invest 96L Kill 55 in Mali

By: Dr. Jeff Masters , 3:40 PM GMT on August 31, 2013

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A tropical wave that emerged from the coast of Africa on Friday (Invest 96L) is headed west-northwest towards the Cape Verde Islands. This wave is struggling against high wind shear of 20 - 25 knots. The shear is expected to drop to the moderate level on Sunday, then increase again to the high level on Monday through Thursday. In their 8 am EDT Saturday Tropical Weather Outlook, NHC put the 5-day odds of development at 40%, and the 2-day odds at 40%. Our reliable models for tropical cyclone genesis show little or no development of 96L. This disturbance is unlikely to affect any land areas except the Cape Verde Islands.


Figure 1. MODIS satellite image of Invest 96L off the coast of Africa, taken at 8:30 am EDT on August 31, 2013. Image credit: NASA.

Disturbance 96L moved very slowly across the Sahel region of Africa during the week, dumping torrential rains on Wednesday that triggered flash floods that killed at least 55 people in Mali's capital city, Bamako. Serious flooding also affected neighboring Burkina Faso, Gambia, Guinea, Niger and Senegal. Buildings have collapsed, roads have been rendered impassable, and valuable farmland is submerged beneath flood water, affecting over 200,000 people. More than 100 homes were swept away as the Niger River burst its banks, bringing down bridges and submerging entire streets.


Figure 2. People hold a rope to help rescuers climbing down a roof of a house in a flooded area of Bamako, Mail, on August 28, 2013. At least 55 people have been killed in flash floods caused by torrential rain. Image credit: HABIBOU KOUYATE/AFP/Getty Images)


Figure 3. MODIS satellite image of tropical wave 96L over Mali on August 28, 2013. The storm dumped torrential rains on Mali's capital city, Bamako, which killed at least 55 people. Image credit: NASA.

Disturbance approaching Lesser Antilles no immediate threat to develop
A tropical wave located about 400 miles east of the Lesser Antilles Islands is moving westward at 15 mph, and has changed little over the past three days. The wave has a modest amount of spin, but only a limited amount of heavy thunderstorm activity. In their 8 am EDT Saturday Tropical Weather Outlook, NHC put the 5-day odds of formation of this disturbance at 10%, and the 2-day odds at 0%. Wind shear is a high 20 - 30 knots over the system, and is expected to stay high through Monday. An area of dry air and dust from the Saharan Air Layer (SAL) surrounds the disturbance and is interfering with development. Wind shear may fall to the moderate level in 4 - 5 days when the wave reaches the Central Caribbean, increasing the odds of development then. Of our three reliable models for predicting genesis, the UKMET, GFS, and European models, only the UKMET model develops the disturbance, predicting it will become a tropical depression south of Haiti on Thursday. The wave will spread heavy rains and gusty winds to the Lesser Antilles Islands on Sunday and Monday.

Jeff Masters

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1419. GatorWX
Quoting 1418. wunderkidcayman:

That's just great more rain


Poor kman and his golf excursion :(
Member Since: January 1, 2008 Posts: 0 Comments: 3797
Quoting 1415. GatorWX:
Doesn't look particularly threatening atm. More rain for the Caymans :)






That's just great more rain
Member Since: June 13, 2009 Posts: 2 Comments: 12710
1417. WxLogic
Good Morning
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I see LLCOC near 14.5N 59.9W
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1415. GatorWX
Doesn't look particularly threatening atm. More rain for the Caymans :)





Member Since: January 1, 2008 Posts: 0 Comments: 3797
at the low level is only see 1 dominant spin but it needs more banding.
Member Since: September 11, 2010 Posts: 1 Comments: 4987
MMMM!!
The winds at the buoys located to the NE and E of 97L just changed from E to a SE component
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1411. GatorWX
And then this one (again, click for animation):



Member Since: January 1, 2008 Posts: 0 Comments: 3797
97L is a MESS of small swirls embedded in a broader circulation
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1409. Kyon5

Quoting 1407. GatorWX:


Right there.

Yeah, we'll see which circulation takes over.
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1408. GatorWX
Quoting 1405. hydrus:
I miss the water...more than words..Tell everyone I said hey would ya..:)


Sure thing! :)
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1407. GatorWX
Quoting 1401. wunderkidcayman:


I don't know how you see this but it ain't happening all that is happening is that the convection is spreading outward


Right there.
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1406. VR46L
Is no one interested in the TW in the Carribean just sayin .. I know its poor looking at the moment but it could pull a fernand in a few days ... I would suggest its a better candidate than 97L who has to come through the Graveyard



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1405. hydrus
Quoting 1399. GatorWX:


Early morning delights! Love sittin' on the porch looking out over the water...

I miss the water...more than words..Tell everyone I said hey would ya..:)
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1403. IKE
GFS continues to do nothing with 97L. ECMWF does little with it. Prove the models wrong 97L.


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000
ABNT30 KNHC 011150
TWSAT

MONTHLY TROPICAL WEATHER SUMMARY
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT SUN SEP 01 2013

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

TROPICAL CYCLONE ACTIVITY IN THE NORTH ATLANTIC BASIN IN AUGUST
WAS BELOW AVERAGE...WITH ONLY TWO TROPICAL STORMS FORMING. BASED
ON A 30-YEAR (1981-2010) CLIMATOLOGY...THREE OR FOUR NAMED STORMS
FORM ON AVERAGE IN THE ATLANTIC BASIN IN AUGUST...WITH ONE OR TWO
BECOMING HURRICANES.

IN TERMS OF ACCUMULATED CYCLONE ENERGY...WHICH MEASURES THE COMBINED
STRENGTH AND DURATION OF TROPICAL STORMS AND HURRICANES...TROPICAL
CYCLONE ACTIVITY THROUGH THE END OF AUGUST WAS ABOUT 70 PERCENT
BELOW THE 1981-2010 AVERAGE.

REPORTS ON INDIVIDUAL CYCLONES...WHEN COMPLETED...ARE AT THE WEB
SITE OF THE NATIONAL HURRICANE CENTER...USE LOWER-CASE LETTERS...
WWW.HURRICANES.GOV/2013ATLAN.SHTML

SUMMARY TABLE

NAME DATES MAX WIND (MPH)
------------------------------------------------- --
TS ANDREA* 5-7 JUN 65
TS BARRY 17-20 JUN 45
TS CHANTAL 8-10 JUL 65
TS DORIAN 24 JUL-3 AUG 60
TS ERIN 15-18 AUG 40
TS FERNAND 25-26 AUG 50
------------------------------------------------- --

* DENOTES A STORM FOR WHICH THE POST-STORM ANALYSIS IS COMPLETE.

$$
HURRICANE SPECIALIST UNIT
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Quoting 1392. GatorWX:
Click this image (30 frame ir loop), it almost looks as if it split, with one area going wnw/nw, the other continuing w/wsw. Didn't a model or two forsee something like that?

http://weather.msfc.nasa.gov/GOESNotStretched/GOE S11152013244q1NuI5.jpg


I don't know how you see this but it ain't happening all that is happening is that the convection is spreading outward
Member Since: June 13, 2009 Posts: 2 Comments: 12710
Quoting 1396. MAweatherboy1:
You can always count on Stewart to raise the odds, lol. Personally, I'd say it's only about the as organized as it was yesterday right now. I'm still not seeing development.

Looking really bad now.
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1399. GatorWX
Quoting 1390. hydrus:
I would be on the deck having coffee with rum in it watching those gulf rumblers...30 years ago..:)


Early morning delights! Love sittin' on the porch looking out over the water...

Member Since: January 1, 2008 Posts: 0 Comments: 3797
Quoting 1384. HuracandelCaribe:


This seems to be the center


havent looked at the radar...good catch....if you look closely though you can see how brad and elongated the circulation is...

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NHC up the % on 97L to 20%/30% no surprise there

000
ABNT20 KNHC 011139
TWOAT

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT SUN SEP 1 2013

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

AN ELONGATED AREA OF LOW PRESSURE...CENTERED JUST TO THE EAST OF
MARTINIQUE...IS PRODUCING A LARGE AREA OF CLOUDINESS AND SCATTERED
THUNDERSTORMS ACROSS MUCH OF THE LESSER ANTILLES AND ADJACENT
WATERS OF THE ATLANTIC AND NORTHEASTERN CARIBBEAN SEA. RADAR DATA
FROM MARTINIQUE AND SATELLITE IMAGERY INDICATE THAT SHOWER ACTIVITY
HAS BECOME A LITTLE BETTER ORGANIZED THIS MORNING...AND NEARBY
SHIPS HAVE BEEN REPORTING WINDS TO NEAR GALE FORCE IN SOME OF THE
STRONG SQUALLS ON THE NORTH SIDE OF THE LOW. ALTHOUGH ENVIRONMENTAL
CONDITIONS ARE ONLY MARGINALLY FAVORABLE...SOME GRADUAL DEVELOPMENT
OF THIS BROAD DISTURBANCE IS POSSIBLE WHILE IT MOVES WESTWARD AT
ABOUT 15 MPH ACROSS THE CARIBBEAN SEA DURING THE NEXT SEVERAL DAYS.
THIS SYSTEM HAS A LOW CHANCE...20 PERCENT...OF BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS...AND A MEDIUM CHANCE...30
PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 5 DAYS.
REGARDLESS OF DEVELOPMENT...LOCALLY HEAVY RAINFALL AND STRONG GUSTY
WINDS ARE EXPECTED TO AFFECT THE PORTIONS OF THE LESSER ANTILLES...
ESPECIALLY THE LEEWARD ISLANDS...TODAY THROUGH MONDAY.
Member Since: June 13, 2009 Posts: 2 Comments: 12710
You can always count on Stewart to raise the odds, lol. Personally, I'd say it's only about the as organized as it was yesterday right now. I'm still not seeing development.

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winds at Barbados changed from W to SW during the past hour or so.
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1393. IKE
TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT SUN SEP 1 2013

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

AN ELONGATED AREA OF LOW PRESSURE...CENTERED JUST TO THE EAST OF
MARTINIQUE...IS PRODUCING A LARGE AREA OF CLOUDINESS AND SCATTERED
THUNDERSTORMS ACROSS MUCH OF THE LESSER ANTILLES AND ADJACENT
WATERS OF THE ATLANTIC AND NORTHEASTERN CARIBBEAN SEA. RADAR DATA
FROM MARTINIQUE AND SATELLITE IMAGERY INDICATE THAT SHOWER ACTIVITY
HAS BECOME A LITTLE BETTER ORGANIZED THIS MORNING...AND NEARBY
SHIPS HAVE BEEN REPORTING WINDS TO NEAR GALE FORCE IN SOME OF THE
STRONG SQUALLS ON THE NORTH SIDE OF THE LOW. ALTHOUGH ENVIRONMENTAL
CONDITIONS ARE ONLY MARGINALLY FAVORABLE...SOME GRADUAL DEVELOPMENT
OF THIS BROAD DISTURBANCE IS POSSIBLE WHILE IT MOVES WESTWARD AT
ABOUT 15 MPH ACROSS THE CARIBBEAN SEA DURING THE NEXT SEVERAL DAYS.
THIS SYSTEM HAS A LOW CHANCE...20 PERCENT...OF BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS...AND A MEDIUM CHANCE...30
PERCENT..
.OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 5 DAYS.
REGARDLESS OF DEVELOPMENT...LOCALLY HEAVY RAINFALL AND STRONG GUSTY
WINDS ARE EXPECTED TO AFFECT THE PORTIONS OF THE LESSER ANTILLES...
ESPECIALLY THE LEEWARD ISLANDS...TODAY THROUGH MONDAY.

A WEAK AREA OF LOW PRESSURE ASSOCIATED WITH A TROPICAL WAVE IS
LOCATED JUST TO THE EAST OF THE NORTHERN CAPE VERDE ISLANDS.
ASSOCIATED SHOWER AND THUNDERSTORM ACTIVITY HAS CONTINUED TO
DECREASE...AND ENVIRONMENTAL CONDITIONS DO NOT APPEAR FAVORABLE FOR
DEVELOPMENT. THIS SYSTEM HAS A LOW CHANCE...NEAR 0 PERCENT...OF
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS...AND A LOW
CHANCE...10 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 5 DAYS...AS IT MOVES GENERALLY WEST-NORTHWESTWARD OVER THE
EASTERN ATLANTIC.

&&

FIVE-DAY FORMATION PROBABILITIES ARE EXPERIMENTAL IN 2013. COMMENTS
ON THE EXPERIMENTAL FORECASTS CAN BE PROVIDED AT...

WWW.NWS.NOAA.GOV/SURVEY/NWS-SURVEY.PHP?CODE=ETWO

$$
FORECASTER STEWART
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1392. GatorWX
Click this image (30 frame ir loop), it almost looks as if it split, with one area going wnw/nw, the other continuing w/wsw. Didn't a model or two forsee something like that?

g

Fixed er
Member Since: January 1, 2008 Posts: 0 Comments: 3797
Quoting 1374. Kyon5:
A center relocation. It is normal that the coordinates flip flop, since it's a disorganized system.

According to the surface analysis, 97L should start moving WNW soon.




It ain't moving WNW any time soon



Quoting 1382. GatorWX:
Quoting 1372. wunderkidcayman:


Well BEST track says it was never at 15N
It was expected to move WSW anyway so no surprise there


I'm pretty sure yesterday afternoon and evening, 15n was the spot bud. It seemed quite evident on visible as convection was fading. I have been known to be wrong. Also, I suppose this is much broader than some of us realized and it could take this thing quite awhile to really do anything. We're all so eager, and honestly I think the NHC is to, to see something happen out there. Conditions aren't very good until the wcarib and possibly shall I say GOM/Bahamas region. It's been my concern a weak system, even a weak ts would track west through the Caribbean into this region since mid-July. If this were to begin developing in the Western Caribbean, things would be substantially worse in many people's opinions on this season. Trough doesn't look like a total fixture on the E Coast. Correct me if I'm wrong anyone.


I ain't saying that it wasn't I was saying that BEST track data

Member Since: June 13, 2009 Posts: 2 Comments: 12710
1390. hydrus
Quoting 1377. GatorWX:


Don't look like much, but they sure sound like a lot.
I would be on the deck having coffee with rum in it watching those gulf rumblers...30 years ago..:)
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1389. VR46L
Quoting 1371. TampaSpin:
Morning....just looked at all the models and only one model supports development of 97L.....that is the CMC model. All others do not develop 97L. I doubt at this point it does develop looking at the shear at about 15-20kts it appears. Secondly, things just don't develop in the area after it passes the islands in that area. Bares watching, but again it appears the models including the GFS is correct. But, that is to be seen YET!


Don't get me wrong I don't see development ,but more than the CMC see it



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Quoting 1383. hydrus:
Good morning Geoff. 97 looks rather interesting. The latest GFS does too. When is the last time you saw a frontal boundary like this..long way out, but..



Morning hydrus. I hope it means a sign of a cool winter down here! 97L is interesting to watch. Here is an excerpt from the Miami NWS Disco...

THERE IS A TROPICAL WAVE LOCATED JUST EAST OF THE LESSER ANTILLES
THAT WILL MOVE WEST NORTHWEST THROUGH THE WEEK...AND PASS SOUTH OF
THE AREA BY LATE THIS WEEK INTO EARLY NEXT WEEKEND. THIS WAVE
COULD BRING IN SOME DEEPER TROPICAL MOISTURE TO THE AREA DURING
THIS TIME FRAME. SO WILL CONTINUE TO MONITOR THE LATEST MODEL RUNS
ON HOW MUCH MOISTURE WORKS INTO THE AREA WITH THE PASSAGE OF THE
TROPICAL WAVE TO THE SOUTH...AND TO SEE IF THE POPS NEED TO BE
RAISED OVER SOUTH FLORIDA FOR LATE THIS WEEK INTO EARLY NEXT WEEK
IN LATER FORECAST.

and from the Key West NWS...

FRIDAY AND SATURDAY -- THE SUBTROPICAL RIDGE SHOULD REMAIN WEAK...BUT
NORTH OF THE FLORIDA KEYS. THE TROPICAL WAVE CURRENTLY APPROACHING
THE WINDWARD ISLANDS MAY BE IN THE VICINITY...WHICH COULD RESULT IN
GREATER SKY COVER/RAIN CHANCES/WIND. FOR NOW...WE HAVE INDICATED
SLIGHTLY-ABOVE-AVERAGE 12-HOUR RAIN CHANCES OF 40 PERCENT FOR THE
FRIDAY-SATURDAY TIME FRAME.
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1387. hydrus
Quoting 1379. GatorWX:


IMO, dry air entrainment into whatever circulation existed and a new low pressure center developed under the heaviest convection. Shear is out of the sw and lots of dry air down there by SA. I'm a little surprised at how far it relocated away from old center. A whole degree, give or take, is pretty substantial.
This system will probably have a few surprises. What a bazaar looking invest.
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1385. GatorWX
Quoting 1380. GeoffreyWPB:
Good morning all...



My guess too is that moisture will stack up near the islands, illustrated a bit in Geoffrey's image, and if true, it'll likely look again like it did yesterday. Most likely, I'd say, a very wet day for those islands. It may look a lot better later on satellite, but that doesn't mean anything is actually happening.
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This seems to be the center
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1383. hydrus
Quoting 1380. GeoffreyWPB:
Good morning all...

Good morning Geoff. 97 looks rather interesting. The latest GFS does too. When is the last time you saw a frontal boundary like this..long way out, but..

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1382. GatorWX
Quoting 1372. wunderkidcayman:


Well BEST track says it was never at 15N
It was expected to move WSW anyway so no surprise there


I'm pretty sure yesterday afternoon and evening, 15n was the spot bud. It seemed quite evident on visible as convection was fading. I have been known to be wrong. Also, I suppose this is much broader than some of us realized and it could take this thing quite awhile to really do anything. We're all so eager, and honestly I think the NHC is to, to see something happen out there. Conditions aren't very good until the wcarib and possibly shall I say GOM/Bahamas region. It's been my concern a weak system, even a weak ts would track west through the Caribbean into this region since mid-July. If this were to begin developing in the Western Caribbean, things would be substantially worse in many people's opinions on this season. Trough doesn't look like a total fixture on the E Coast. Correct me if I'm wrong anyone.
Member Since: January 1, 2008 Posts: 0 Comments: 3797
Quoting 1379. GatorWX:


IMO, dry air entrainment into whatever circulation existed and a new low pressure center developed under the heaviest convection. Shear is out of the sw and lots of dry air down there by SA. I'm a little surprised at how far it relocated away from old center. A whole degree, give or take, is pretty substantial.
A whole degree in hours.How many miles that means?
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Good morning all...

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1379. GatorWX
Quoting 1370. prcane4you:
Yesterday at 15 now 14.What the hell happened.


IMO, dry air entrainment into whatever circulation existed and a new low pressure center developed under the heaviest convection. Shear is out of the sw and lots of dry air down there by SA. I'm a little surprised at how far it relocated away from old center. A whole degree, give or take, is pretty substantial.
Member Since: January 1, 2008 Posts: 0 Comments: 3797
1378. Kyon5




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1377. GatorWX


Don't look like much, but they sure sound like a lot.
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1376. Kyon5

.

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1375. SLU
Quoting 1360. stoormfury:
morning
well a wet day in st lucia, SLU feel very soory for the Bexon and other areas prone to serious flooding in suci


Yup .. could be a very wet day with this slow moving system.
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1374. Kyon5
Quoting 1372. wunderkidcayman:


Well BEST track says it was never at 15N
It was expected to move WSW anyway so no surprise there
A center relocation. It is normal that the coordinates flip flop, since it's a disorganized system.

According to the surface analysis, 97L should start moving WNW soon.


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Quoting 1364. Tropicsweatherpr:


Coincidence that I live in Miramar. (Calle Estado) Yes,PR is a beautiful island with lovely people.
Beautiful island YES.Lovely people forget it.
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Quoting 1370. prcane4you:
Yesterday at 15 now 14.What the hell happened.


Well BEST track says it was never at 15N
It was expected to move WSW anyway so no surprise there
Member Since: June 13, 2009 Posts: 2 Comments: 12710
Morning....just looked at all the models and only one model supports development of 97L.....that is the CMC model. All others do not develop 97L. I doubt at this point it does develop looking at the shear at about 15-20kts it appears. Secondly, things just don't develop in the area after it passes the islands in that area. Bares watching, but again it appears the models including the GFS is correct. But, that is to be seen YET!
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Quoting 1366. GatorWX:
Yesterday at 15 now 14.What the hell happened.
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Quoting 1359. GatorWX:
hmmm, It looked much better yesterday afternoon imo.

Stretched!..and not stacked yet at all.



It's got issues!

That could change very quickly

Quoting 1361. nrtiwlnvragn:



Martinique
01 06:30 N 3

Saint Lucia
01 06:00 Calm

Barbados
01 06:00 W 3


And a bouy near 15.8N 57.4W shows E wind
Member Since: June 13, 2009 Posts: 2 Comments: 12710

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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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