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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96 hours.
Member Since: September 27, 2007 Posts: 1 Comments: 19608
Quoting 161. unknowncomic:
I would like to see Dr Masters clarify what the NAM is useful for.


not Dr. Masters but since I have been on the blog but it was stated the NAM was great in modeling atmospheric conditions and not so much a tropical model..
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Don't get your hopes up on this one. Odds are heavily against it, lots of shear ahead. At least it's something to track though, and if it can survive the next few days then who knows.

12z CMC is running now, we'll see what it does.
Member Since: February 11, 2012 Posts: 79 Comments: 7306
Member Since: March 12, 2013 Posts: 7 Comments: 11121
Plenty of land interaction with 97L.. Models here
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Quoting 160. Patrap:
Gotta say 97L is looking much better. Future DMAX will be interesting.
Member Since: August 2, 2011 Posts: 0 Comments: 1722
163. Relix
There we go. Post 50W miracle, almost always works. So we have an Erika/Irene/Jeanne type of development here. Should be fun.
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162. JRRP
Quoting Levi32:
Invest 97L (very) early models:


so we have 97L... not bad
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Quoting 146. Sfloridacat5:
NAM has been showing development in the Caribbean for the past 3 days.
I would like to see Dr Masters clarify what the NAM is useful for.
Member Since: August 2, 2011 Posts: 0 Comments: 1722
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Quoting 135. hurricanes2018:
HERE ABOUT THREE STORMS ON THE CMC!
The path from the CMC is a potentially dangerous one for Florida. Far to early to in the game to consider. The new CMC has initialized 97L way to the south.
Member Since: September 27, 2007 Posts: 1 Comments: 19608
Quoting 148. Levi32:
Invest 97L (very) early models:





that's not good
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157. ryang
97L kinda reminds of Issac from last year.
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Quoting 135. hurricanes2018:
HERE ABOUT THREE STORMS ON THE CMC!


Very interesting show a path very similar to Chantal earlier this year.
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Quoting 152. ncstorm:


Levi, I didnt know you had these maps on your page..if only you got the euro and I will leave allan's page alone..


Yup, under my ATCF page.
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Quoting 148. Levi32:
Invest 97L (very) early models:

Link So Levi how do you think it looks?
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with my knowledge of satellite interpretation of winds it appears that 97L is very close to TD status
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Quoting 148. Levi32:
Invest 97L (very) early models:



Levi, I didnt know you had these maps on your page..if only you got the euro and I will leave allan's page alone..
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Vorticity is the best yet for 97L except at the upper levels which show nil.

Member Since: August 2, 2011 Posts: 0 Comments: 1722
Quoting 93. Tazmanian:
we have 97L


BEGIN
NHC_ATCF
invest_al972013.invest
FSTDA
R
U
040
010
0000
201308311639
NONE
NOTIFY=ATRP
END
INVEST, AL, L, , , , , 97, 2013, DB, O, 2013083112, 9999999999, , , , , , METWATCH, , AL972013
AL, 97, 2013083112, , BEST, 0, 150N, 540W, 25, 0, DB, 0, , 0, 0, 0, 0,


Great job. I knew it was only a matter of time before we have an invest. Intialization is right where I saw the center on the previous blog at 15N/54W. Models are agressive strengthening it rather quickly based on the SHIPS.
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Quoting 141. CybrTeddy:


Yes. Although I don't think that will happen.


this season has been perplexing for everyone who forecasts..strange factors indeed are at work here..

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Invest 97L (very) early models:

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I see we have a new invest.
What %s do you think the NHC will give it?
A 20/30
B 30/30
C 20/20
D 20/40
E 20/50
F 20/60

I think A or B.
Member Since: June 11, 2013 Posts: 18 Comments: 2211
NAM has been showing development in the Caribbean for the past 3 days.
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Quoting 133. K8eCane:
if we are all still here, that is.


You got that right sister!
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Quoting 132. MiamiHurricanes09:
SHIPS forecasting a hurricane into Hispañola in a little under 5 days.


lol
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Quoting 104. tornadodude:


We had radar accurately measure winds of 296 mph. The only thing I've read so far about it being dismissed is that the EF scale is based solely on damage. That is a flawed system.

If that's the case, then they have to reconsider the width as well, as that was determined by radar.

It's not irrelevant. It's about consistency in a scientific field.
Oh ok I got you. I always thought it was based solely on damage. Not realizing that the scale itself has a range of wind speeds that determine the rating. I remember learning about the old Fujita scale in elementary school I forgot other than wind speeds what else the scale had measured. Now I see they have damage indicators in the enhanced one. At least they still use linear formulas.
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Quoting 134. ncstorm:


Teddy, the CMC was showing development of 97L before the UKMET..if this plays out to a TC formation..will you be giving the CMC props?


Yes. Although I don't think that will happen.
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The early models will have no choice at this time but to move 97L over the Dr and Haiti and move it towards the Bahamas and the eastern US. the high is still in place but a weakness in the ridge and a trough in few days will want to pick up 97l and move it NW.
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Quoting 136. SLU:
Hmmm...

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 25 27 28 29 31 36 42 50 56 62 66 70 71
V (KT) LAND 25 27 28 29 31 36 42 50 56 62 66 70 60
V (KT) LGE mod 25 27 28 30 31 34 38 45 54 66 76 86 73
They show development by 72hr?
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Quoting 125. MiamiHurricanes09:
Definitely, global models often underestimate intensity, as well as overestimate it...the CMC in particular, but both the GFS and ECMWF are essentially depicting no tropical cyclone formation of any sort through the next 10 days.

That means something, to me at least.

The Global models have been quite conservative this year with TC formation, the GFS is a little more agressive than the Euro, but even that model doesn't see much in the next week or so. Just a few days ago GFS saw 2 storms coming off of Africa behind 96L and a 3rd one forming in the GoM, and now they don't see much at all. Yet, I still expect the Atlantic will spring up in activity sometime in the next two weeks.
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So there are some models that agree with the NAM?
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136. SLU
Hmmm...

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 25 27 28 29 31 36 42 50 56 62 66 70 71
V (KT) LAND 25 27 28 29 31 36 42 50 56 62 66 70 60
V (KT) LGE mod 25 27 28 30 31 34 38 45 54 66 76 86 73
Member Since: Posts: Comments:
HERE ABOUT THREE STORMS ON THE CMC!
Member Since: March 12, 2013 Posts: 7 Comments: 11121
Quoting 129. CybrTeddy:


Means more to me that the UKMET is showing development, especially when considering the poor outputs of both the GFS and ECMWF at 120+.


Teddy, the CMC was showing development of 97L before the UKMET..if this plays out to a TC formation..will you be giving the CMC props?
Member Since: Posts: Comments:
if we are all still here, that is.
Member Since: April 26, 2006 Posts: 5 Comments: 3041
SHIPS forecasting a hurricane into Hispañola in a little under 5 days.
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131. SLU
BEGIN
NHC_ATCF
invest_al972013.invest
FSTDA
R
U
040
010
0000
201308311647
NONE
NOTIFY=ATRP
END
INVEST, AL, L, , , , , 97, 2013, DB, O, 2013083112, 9999999999, , , , , , METWATCH, , AL972013
AL, 97, 2013083012, , BEST, 0, 145N, 485W, 20, 1009, DB, 0, , 0, 0, 0, 0,
AL, 97, 2013083018, , BEST, 0, 147N, 502W, 20, 1009, DB, 0, , 0, 0, 0, 0,
AL, 97, 2013083100, , BEST, 0, 148N, 513W, 20, 1009, DB, 0, , 0, 0, 0, 0,
AL, 97, 2013083106, , BEST, 0, 149N, 526W, 20, 1009, DB, 0, , 0, 0, 0, 0,
AL, 97, 2013083112, , BEST, 0, 150N, 540W, 25, 1008, DB, 34, NEQ, 0, 0, 0, 0, 1010, 150, 0, 0, 0, L, 0, ,
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well one thing for sure. By next week this time, we will know how it played out!!
Member Since: April 26, 2006 Posts: 5 Comments: 3041
Quoting 125. MiamiHurricanes09:
Definitely, global models often underestimate intensity, as well as overestimate it...the CMC in particular, but both the GFS and ECMWF are essentially depicting no tropical cyclone formation of any sort through the next 10 days.

That means something, to me at least.


Means more to me that the UKMET is showing development, especially when considering the poor outputs of both the GFS and ECMWF at 120 hours . TAWx13, if you're out there mind posting the Euro and GFS verification results from the last few days? GFS did record poorly as I recall.
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Quoting 114. WoodyFL:
wow these models sure want to bring 96 back south



here we go loop-de-lu, here we go loop-de-lie
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Quoting 121. SLU:


Invest 97L
Inflow has increase but the trades speed up south of PR.
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126. SLU
The conditions are way better than the NHC thinks


* ATLANTIC SHIPS INTENSITY FORECAST *
* GOES AVAILABLE, OHC AVAILABLE *
* INVEST AL972013 08/31/13 12 UTC *

TIME (HR) 0 6 12 18 24 36 48 60 72 84 96 108 120
V (KT) NO LAND 25 27 28 29 31 36 42 50 56 62 66 70 71
V (KT) LAND 25 27 28 29 31 36 42 50 56 62 66 70 60
V (KT) LGE mod 25 27 28 30 31 34 38 45 54 66 76 86 73
Storm Type TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP TROP

SHEAR (KT) 15 11 13 11 4 6 0 5 5 4 8 6 11
SHEAR ADJ (KT) -1 -3 0 -1 -2 -1 -1 -4 -2 -2 -3 0 -2
SHEAR DIR 256 257 241 250 261 200 241 188 304 247 296 214 262
SST (C) 28.2 28.4 28.5 28.6 28.6 28.8 28.9 29.0 29.1 29.1 29.1 29.1 29.1
POT. INT. (KT) 140 142 144 145 145 148 149 151 153 153 154 154 154
ADJ. POT. INT. 137 138 139 140 139 142 143 145 147 149 150 148 147
200 MB T (C) -54.2 -53.9 -53.8 -53.8 -53.9 -53.6 -53.8 -53.5 -53.6 -53.4 -53.6 -53.3 -53.3
TH_E DEV (C) 10 10 10 10 10 11 11 11 10 11 10 11 11
700-500 MB RH 52 51 50 52 55 54 57 60 62 61 63 61 63
GFS VTEX (KT) 8 8 8 8 7 6 6 5 LOST LOST LOST LOST LOST
850 MB ENV VOR 22 24 23 18 19 26 34 48 56 55 48 45 34
200 MB DIV 16 30 18 26 23 17 11 1 3 23 16 24 0
700-850 TADV -1 -1 -4 -1 0 -3 -1 -1 1 1 6 6 5
LAND (KM) 890 798 714 637 568 473 435 444 367 268 190 75 32
LAT (DEG N) 15.0 15.1 15.1 15.1 15.0 14.9 14.7 14.7 14.9 15.5 16.4 17.5 18.6
LONG(DEG W) 54.0 55.1 56.1 57.1 58.0 59.8 61.4 63.0 64.7 66.5 68.5 70.6 72.8
STM SPEED (KT) 12 10 10 9 9 8 8 8 8 10 11 11 12
HEAT CONTENT 32 27 28 32 39 48 29 44 62 49 37 25 22

FORECAST TRACK FROM BAMM INITIAL HEADING/SPEED (DEG/KT):275/ 12 CX,CY: -11/ 1
T-12 MAX WIND: 20 PRESSURE OF STEERING LEVEL (MB): 691 (MEAN=624)
GOES IR BRIGHTNESS TEMP. STD DEV. 50-200 KM RAD: 30.2 (MEAN=14.5)
% GOES IR PIXELS WITH T < -20 C 50-200 KM RAD: 20.0 (MEAN=65.0)

INDIVIDUAL CONTRIBUTIONS TO INTENSITY CHANGE
6 12 18 24 36 48 60 72 84 96 108 120
-------------------------------------------------- --------
SAMPLE MEAN CHANGE 1. 2. 3. 4. 6. 8. 9. 11. 12. 12. 13. 14.
SST POTENTIAL 0. 0. 1. 2. 6. 11. 18. 23. 27. 30. 33. 35.
VERTICAL SHEAR MAG 1. 2. 3. 4. 7. 9. 11. 12. 13. 13. 14. 13.
VERTICAL SHEAR ADJ 0. 0. 0. 1. 1. 2. 3. 3. 3. 3. 3. 2.
VERTICAL SHEAR DIR 0. -1. -2. -3. -5. -8. -9. -10. -11. -12. -14. -15.
PERSISTENCE 1. 1. 2. 2. 2. 2. 2. 1. 1. 1. 0. 0.
200/250 MB TEMP. 0. 0. 0. 1. 1. 1. 2. 2. 2. 3. 3. 3.
THETA_E EXCESS 0. 0. 0. 0. 0. 0. 0. 0. 1. 0. 1. 1.
700-500 MB RH 0. 0. 0. 0. 0. 0. -1. -1. -1. -1. -1. -1.
GFS VORTEX TENDENCY 0. 0. -1. -1. -2. -3. -4. -5. -5. -5. -5. -5.
850 MB ENV VORTICITY 0. 0. 0. 0. 0. 0. 0. 1. 1. 1. 1. 1.
200 MB DIVERGENCE 0. 0. 0. 0. 0. 0. 0. -1. -1. -1. 0. 0.
850-700 T ADVEC 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
ZONAL STORM MOTION 0. 0. 0. 1. 1. 1. 2. 2. 2. 2. 3. 3.
STEERING LEVEL PRES 0. 0. 0. 0. -1. -1. -1. -1. -1. -1. -1. -1.
DAYS FROM CLIM. PEAK 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
GOES PREDICTORS -1. -2. -3. -4. -5. -5. -5. -5. -5. -5. -4. -4.
OCEAN HEAT CONTENT 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.
-------------------------------------------------- --------
TOTAL CHANGE 2. 3. 4. 6. 11. 17. 25. 31. 37. 41. 45. 46.

** 2013 ATLANTIC RI INDEX AL972013 INVEST 08/31/13 12 UTC **
( 30 KT OR MORE MAX WIND INCREASE IN NEXT 24 HR)

12 HR PERSISTENCE (KT): 5.0 Range:-49.5 to 33.0 Scaled/Wgted Val: 0.7/ 1.9
850-200 MB SHEAR (KT) : 11.0 Range: 28.8 to 2.9 Scaled/Wgted Val: 0.7/ 0.8
STD DEV OF IR BR TEMP : 30.2 Range: 37.5 to 2.9 Scaled/Wgted Val: 0.2/ 0.3
850-700 MB REL HUM (%): 67.8 Range: 43.2 to 93.5 Scaled/Wgted Val: 0.5/ 0.6
POT = MPI-VMAX (KT) : 113.3 Range: 28.4 to 139.1 Scaled/Wgted Val: 0.8/ 0.5
Heat content (KJ/cm2) : 31.6 Range: 0.0 to 155.1 Scaled/Wgted Val: 0.2/ 0.1
D200 (10**7s-1) : 22.6 Range:-23.1 to 181.5 Scaled/Wgted Val: 0.2/ 0.1
% area w/pixels <-30 C: 19.0 Range: 15.3 to 100.0 Scaled/Wgted Val: 0.0/ 0.0

Prob of RI for 25 kt RI threshold= 18% is 1.5 times the sample mean(11.9%)
Prob of RI for 30 kt RI threshold= 10% is 1.3 times the sample mean( 7.6%)
Prob of RI for 35 kt RI threshold= 5% is 1.2 times the sample mean( 4.6%)
Prob of RI for 40 kt RI threshold= 1% is 0.3 times the sample mean( 3.0%)

## ANNULAR HURRICANE INDEX (AHI) AL972013 INVEST 08/31/13 12 UTC ##
## STORM NOT ANNULAR, SCREENING STEP FAILED, NPASS=3 NFAIL=4 ##
## AHI= 0 (AHI OF 100 IS BEST FIT TO ANN. STRUC., 1 IS MARGINAL, 0 IS NOT ANNULAR) ##

** PROBLTY OF AT LEAST 1 SCNDRY EYEWL FORMTN EVENT AL972013 INVEST 08/31/2013 12 UTC **
TIME(HR) 0-12 12-24(0-24) 24-36(0-36) 36-48(0-48)
CLIMO(%) 0 0( 0) 0( 0) 0( 0) <-- PROB BASED ON INTENSITY ONLY
PROB(%) 0 0( 0) 0( 0) 0( 0) <-- FULL MODEL PROB (RAN NORMALLY)
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Quoting 122. CybrTeddy:


I can name several occasions where the models develop a storm, but all of them unanimously fail to make it a hurricane, although that's a little different from missing it altogether.
Definitely, global models often underestimate intensity, as well as overestimate it...the CMC in particular, but both the GFS and ECMWF are essentially depicting no tropical cyclone formation of any sort through the next 10 days.

That means something, to me at least.
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Quoting 113. SLU:
Invest 97L


I actually think it has a chance later down the road. Who knows
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12z CMC up to 180 hours





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Quoting 106. MiamiHurricanes09:
Because they're the best aid we have in forecasting tropical cyclones. Even though they may be hit or miss, how often does a hurricane develop when there's absolutely no model support for it? An extremely rare occasion I'd say.


I can name several occasions where the models develop a storm, but all of them unanimously fail to make it a hurricane, although that's a little different from missing it altogether.
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121. SLU
Quoting 115. Gearsts:
Can you link me to that loop?


Invest 97L
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when one looks at the sat pics it is very clear that the the low level clouds are streaming from the south towards the LLC. This is indicative of a developing system
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xD
Time: 16:19:30Z
Coordinates: 15.35N 52.0W
Acft. Static Air Press: 163.2 mb (~ 4.82 inHg)
Acft. Geopotential Hgt: 13,729 meters (~ 45,043 feet)
Extrap. Sfc. Press: -
D-value: 662 meters (~ 2,172 feet)
Flt. Lvl. Wind (30s): From 271° at 4 knots (From the W at ~ 4.6 mph)
Air Temp: -66.5°C* (~ -87.7°F*)
Dew Pt: -*
Peak (10s) Flt. Lvl. Wind: 4 knots (~ 4.6 mph)
SFMR Peak (10s) Sfc. Wind: -
SFMR Rain Rate: -
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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.