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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The positive Atlantic tripole is trying to make a return.

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1218. beell
Quoting 1216. Levi32:


Sorry, G-IV was what I meant.


NP. As long as we're talking about the same data.
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1217. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Cyclone Advisory #2
Gale Warning
TROPICAL STORM YUTU (T1316)
12:00 PM JST September 1 2013
==============================

Midway Island Waters

At 3:00 AM UTC, Tropical Storm Yutu (1002 hPa) located at 32.9N 176.4E has 10 minute sustained winds of 35 knots with gusts of 50 knots. The cyclone is reported as moving northeast at 6 knots.

Gale Force Winds
=================
210 NM from the center in southeast quadrant
120 NM from the center in northwest quadrant

Dvorak Intensity: T2.5

Forecast and Intensity
========================
24 HRS: 33.7N 178.3E - 35 knots (CAT 1/Tropical Storm) Midway Island Waters
45 HRS: 33.7N 179.2E - 35 knots (CAT 1/Tropical Storm) Midway Island Waters
69 HRS: 33.6N 178.8W - 35 knots (CAT 1/Tropical Storm) Midway Island Waters
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1216. Levi32
Quoting 1189. beell:
Was there a Global Hawk mission over the wave today?


Sorry, G-IV was what I meant.
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Quoting 1211. IKE:

6h
MJO: what suppresses in August
may not in September.. Will explain tonight. Have to eat with family
first. In RI with all my relatives...................................


Wake up Joe...you never explained it...lol.


he also said he may not be able to do the video until tomorrow.
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Quoting 1213. KoritheMan:


I saw it first.


You saw NOTHIN!

lol

Come hang out in TX if it lands here. We got good BBQ.
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Quoting 1210. redwagon:


Good BOY! still my cane.


I saw it first.
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Poor 97L can't get no respect. Maybe tommorrow.
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1211. IKE

6h
MJO: what suppresses in August
may not in September.. Will explain tonight. Have to eat with family
first. In RI with all my relatives...................................


Wake up Joe...you never explained it...lol.
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Quoting 1203. KoritheMan:


Nathan, stop that. It reminds me too much of Walmart, a palce I just got out of.


Good BOY! still my cane.
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1209. pottery
Quoting SLU:


Hey Pottery

I hope you weren't affected by the tornado.

Never even heard about that until the next day.
Got 2.5'', but just west of here there was plenty more.

Looks like that stuff at 45W is coming.......
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The GFS' AC score is slightly better today after dipping to a near record low earlier in the week (according to Dr. Maue).



ECMWF continues to perform less than ideally:



CMC is not doing so well either:

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Quoting 1200. sar2401:

Either the NHC was way off the mark at 8:00 or it's going past the Antilles as a TW.




LOL, I can read, SAR, and so noted that the NHC was probably right, but it's a blog, I can have an opinion, albeit even wrong. ;P I don't hang on every word of the NHC, just like I don't hang on every run of a model. I observe, relate my thoughts. I never pretend to equate that they are correct.
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1206. pottery
Quoting sar2401:

Either the NHC was way off the mark at 8:00 or it's going past the Antilles as a TW.

CLOUDINESS AND SHOWERS ASSOCIATED WITH THIS SYSTEM REMAIN DISORGANIZED...AND THERE IS NO EVIDENCE OF A WELL-DEFINED SURFACE WIND CIRCULATION. ENVIRONMENTAL CONDITIONS ARE NOT
CURRENTLY FAVORABLE FOR DEVELOPMENT...BUT COULD BECOME A LITTLE MORE CONDUCIVE FOR SOME DEVELOPMENT WHEN THE WAVE REACHES THE
WESTERN CARIBBEAN SEA IN 4 OR 5 DAYS.


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1205. IKE
@ 66 hours...


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1204. SLU
Quoting 1126. pottery:

Yeah, I would go along with that.
But if it keeps building those strong thunderstorms and can hang onto them tomorrow, I'll change my mind.

It's looking 'iffy'.


Hey Pottery

I hope you weren't affected by the tornado.
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Quoting 1202. Astrometeor:


Sorry, let me refer you to customer service. I am not qualified to answer your questions.


Nathan, stop that. It reminds me too much of Walmart, a place I just got out of.
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Quoting 1191. KoritheMan:
Is this my hurricane?

Is this my hurricane!?

IS THIS MY HURRICANE?!

I'M WAITING FOR YOU


Sorry, let me refer you to customer service. I am not qualified to answer your questions.
Member Since: July 2, 2012 Posts: 79 Comments: 8246
1201. IKE
00Z GFS @ 54 hours....


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1200. sar2401
Quoting moonlightcowboy:
Great observations from several on 97L. At the broad circ continues to move west or maybe even slightly south/southwest, the faster low level easterlies are having less effect. Again, I think this allows the low-level westerlies to better wrap into the system, but we may see multiple vortices or a main center reformation - not atypical of early cyclogenesis. And, it' probably whey we're effectively seeing two lobe of convection firing.

It's forward motion should slow, mid-level shear is non-existent, and as these westerlies wrap, a more dominant circulation should ensue with convection building singularly directly overhead. The ULAC is helping stave off shearing except maybe on the northern side, but I'm not sure that won't actually aid development if it can get some height going over a dominant coc.

The NHC is probably right, but I'm thinking 97L has a more than a decent chance still to get something going before it passes into the east Caribbean.

Either the NHC was way off the mark at 8:00 or it's going past the Antilles as a TW.

CLOUDINESS AND SHOWERS ASSOCIATED WITH THIS SYSTEM REMAIN DISORGANIZED...AND THERE IS NO EVIDENCE OF A WELL-DEFINED SURFACE WIND CIRCULATION. ENVIRONMENTAL CONDITIONS ARE NOT
CURRENTLY FAVORABLE FOR DEVELOPMENT...BUT COULD BECOME A LITTLE MORE CONDUCIVE FOR SOME DEVELOPMENT WHEN THE WAVE REACHES THE
WESTERN CARIBBEAN SEA IN 4 OR 5 DAYS.
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1199. beell
LOL, TA. Had to check. Thought you had a link I didn't. Couldn't have that could we?
:)
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Quoting 1189. beell:
Was there a Global Hawk mission over the wave today?

I don't like these hints you give, beell. D:

No, there was not. My mistake. It was a NOAA Gulfstream aircraft.
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Quoting 1191. KoritheMan:
Is this my hurricane?

Is this my hurricane!?

IS THIS MY HURRICANE?!

I'M WAITING FOR YOU


Ahm..no, it's mine.
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1196. pottery
Quoting hurricanes2018:
big hurricane moving west! 989mb

For sept. 16th.....
My forecast might come to pass.
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1195. beell
Product: NOAA Temp Drop (Dropsonde) Message (UZNT13 KWBC)
Transmitted: 31st day of the month at 20:23Z
Agency: National Oceanic and Atmospheric Administration (NOAA)
Aircraft: Gulfstream IV-SP (G-IV) (Reg. Num. N49RF)
Mission: Non-Tasked Mission, possibly not tropical (flight in the North Atlantic basin)
Mission Identifier: Wave (Probably storm name)
Observation Number: 25

Link
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1194. sar2401
Take a look at 7N,45W. Looks at least as well developed as 97L and it's headed for Brazil!
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1193. pottery
Quoting redwagon:



OK, that's looking like a circle to me.......
Closed, reasonably tight, etc.

What's the catch ?
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Quoting 1182. sar2401:

Of course, the models in general did much worse in 2004, but they did terrible for Jeanne. I don't think there was one model that got track or intensity right.


Of course, lol, don't they always? ;) Totally why I never even glance at a model until something is up and actually churning! ;)
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Is this my hurricane?

Is this my hurricane!?

IS THIS MY HURRICANE?!

I'M WAITING FOR YOU
Member Since: Posts: Comments:
Great observations from several on 97L. At the broad circ continues to move west or maybe even slightly south/southwest, the faster low level easterlies are having less effect. Again, I think this allows the low-level westerlies to better wrap into the system, but we may see multiple vortices or a main center reformation - not atypical of early cyclogenesis. And, it's probably whey we're effectively seeing two lobes of convection firing.

Its forward motion should slow, mid-level shear is non-existent, and as these westerlies wrap, a more dominant circulation should ensue with convection building singularly directly overhead. The ULAC is helping stave off shearing except maybe on the northern side, but I'm not sure that won't actually aid development if it can get some height going over a dominant coc.

The NHC is probably right, but I'm thinking 97L has a more than a decent chance still to get something going before it passes into the east Caribbean.
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1189. beell
Was there a Global Hawk mission over the wave today?
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big hurricane moving west! 989mb
Member Since: March 12, 2013 Posts: 7 Comments: 11029
1187. sar2401
Quoting kmanislander:
Well I have a golf game in the morning so its off to bed for me. Catch you all tomorrow.

GN, KMan, hope you break par. :-)
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Quoting 1180. pottery:

OK, I cede to your better knowledge on these things.
It would be good to have confirmation from ASCAT or a buoy though.
If there is indeed a COC, in the low levels, this would change things, even though the system is elongated.

At this stage, I'm agreeing with the NHC, for the next couple days.


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Well I have a golf game in the morning so its off to bed for me. Catch you all tomorrow.
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Quoting 1181. kmanislander:


A little to the NE near 57/58 West. Barbados is bisected by 13 N and 60 W.


True its late and my head is foggy. Everyone have a goodnight , we'll see what tomorrow brings.
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1183. sar2401
Quoting Levi32:


They have.


Ah, see, that's what happens when I go out to walk the dog. :-) What center are models using to initialize from? Seems like many of them are still using bogus vortexes.
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1182. sar2401
Quoting SFLWeatherman:
How did the models do for hurricane jeanne in 2004?

Of course, the models in general did much worse in 2004, but they did terrible for Jeanne. I don't think there was one model that got track or intensity right.
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Quoting 1176. stormpetrol:
Winds out of Barbados are 4mph out the North, center should be east of that Island.


A little to the NE near 57/58 West. Barbados is bisected by 13 N and 60 W.

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1180. pottery
Quoting Levi32:


The cumulus clouds in the region are very close to the surface. In fact, it is at the mid-levels that it is not closed according to global hawk data. Westerlies exist at the surface.

OK, I cede to your better knowledge on these things.
It would be good to have confirmation from ASCAT or a buoy though.
If there is indeed a COC, in the low levels, this would change things, even though the system is elongated.

At this stage, I'm agreeing with the NHC, for the next couple days.
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According to this its closed albeit weak.
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Quoting 1173. Bluestorm5:
Already said on Twitter he isn't doing it due to moving back into college tomorrow.
thanks
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1177. Levi32
Quoting 1174. sar2401:

Well, you know a lot more about these things than I do, but it certainly looks a lot more like a pair of blobs right now compared to what it looked like this afternoon. Seems odd to me that the NHC hasn't already identified this as a low if it's a clear as you say. Las I saw was it was too weak to classify.


They have.

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Winds out of Barbados are 4mph out the North, center should be east of that Island.
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Is the main problem(s)for 97L the fairly high shear, the elongated circulation, and the lack of convergence?
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1174. sar2401
Quoting Levi32:


Daylight.


Well, you know a lot more about these things than I do, but it certainly looks a lot more like a pair of blobs right now compared to what it looked like this afternoon. Seems odd to me that the NHC hasn't already identified this as a low if it's a clear as you say. Last I saw was it was too weak to classify.
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Quoting 1170. bigwes6844:
Tidbit?
Already said on Twitter he isn't doing it due to moving back into college tomorrow.
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1172. GatorWX
Too bad we don't have an ascat pass, time for bed. Keep an eye on it guys will ya?

I think I tend to agree it's simply a very broad low pressure perhaps lacking a discernible center of circulation. It's certainly not a nice tight center needed to build height imo. Things could change if whatever is down there could hold on to some deep convection overnight. I'll see you all and 97L in the morning. Should be able to make a better judgement then.
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Quoting 1163. sar2401:

Indeed, but that was this afternoon, and it wasn't low level, as I recall. It looks quite disorganized tonight compared to this afternoon.


Well, it certainly hasn't opened back up since then.

Skye? TRMM?
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Quoting 1145. Levi32:


It's closed, just broad and elongated WSW to ENE. There is "no convergence" because the circulation is very weak with few thunderstorms, as one would expect. Development, if any, will be slow, and may take a complete hiatus between 65W and 75W due to the typical Caribbean trade wind trap. One can see why this wave has to be watched farther west, though.
Tidbit?
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Quoting 1154. TropicalAnalystwx13:

There's a very robust circulation. Both satellite and data from the Global Hawk mission this afternoon showed that. It is broad in nature though...very broad.


A lot has changed with this since the aircraft left station several hours ago. No one disputes there is a low "spinning" out there I just dont think it is closed anymore unlike earlier today when it certainly appeared to be.

I don't think it matters much either way because it will soon enter the Caribbean unclassified unless a miracle happens overnight.
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About JeffMasters

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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