Caribbean disturbance 99L a dangerous rainfall threat for Haiti, Jamaica, and Cuba

By: Dr. Jeff Masters , 4:12 PM GMT on October 20, 2012

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A tropical wave embedded in a large trough of low pressure (Invest 99L) covers a large portion of the Central Caribbean between Hispaniola and the northern coast of South America. This storm has the potential to be a dangerous rainfall threat for Haiti, Jamaica, and eastern Cuba. The disturbance is headed west at less than 5 mph, is over very warm waters of 29°C, and is in a moist environment. 99L has a large area of heavy thunderstorms that are beginning to show some organization, as seen on visible satellite loops. Wind shear is a low 5 - 10 knots, and is forecast to be in the low to moderate range, 5 - 20 knots, through Tuesday. This should allow for some steady development of 99L, and there has been a good deal of model support for 99L becoming a tropical depression by Wednesday. Steering currents favor a continued slow westward movement for 99L through Tuesday, which will bring a multi-day period of heavy rains to Haiti, Jamaica, and eastern Cuba beginning on Sunday. The Dominican Republic may also see some heavy rains, though not as great. On Wednesday, a strong trough of low pressure will approaching the Eastern U.S., and the GFS and ECMWF models predict that this trough will turn 99L to the north, bringing the storm into the southeast Bahama Islands on Thursday or Friday. In their 8 am EDT tropical weather outlook, NHC gave 99L a 30% chance of developing into a tropical cyclone by Monday morning. I put these odds higher, at 40%. An Air Force hurricane hunter aircraft is scheduled to investigate 99L on Sunday afternoon.


Figure 1. Morning satellite image of Invest 99L.

Invest 90L in the middle Atlantic
A tropical wave (Invest 90L) about 1000 miles east-northeast of the northernmost Lesser Antilles Islands is headed west-northwest at about 10 mph. The disturbance has a modest amount of heavy thunderstorms, as seen on visible satellite images, and has gotten tangled up with an upper-level low pressure system. This upper-level low is pumping cool, dry air into the disturbance, which will keep any development slow over the next few days. Wind shear is a high 20 - 25 knots, but is forecast to drop to the moderate range, 10 - 20 knots, Sunday through Monday. This may allow for some slow development of 90L before it encounters very high wind shear of 20 - 40 knots on Tuesday and Wednesday. None of the reliable computer models develop 90L into a tropical cyclone. It's unlikely that 90L will affect any land areas. In their 8 am EDT tropical weather outlook, NHC gave 90L a 20% chance of developing into a tropical cyclone by Monday morning.

Jeff Masters

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Quoting Dakster:


After marriage and kids, my life ended....

Not really, just got a lot more hectic though.


Aw come on. The honeydos much keep you occupied?
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Quoting wxchaser97:

I pay attention in biology even though it isn't weather.


I can tell, that made my day.
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Quoting TropicalAnalystwx13:

No excuse. I have 22,154 comments and I've been here since July 2010. ;)

Before anybody asks, yes, I have a life.

Well, that shows you something... I have less than 4000 comments and yet I joined only 3 months after you... Cody, I'm sorry to say, but do u get out much? I mean seriously you have 5x as many comments... You rank 3rd place for most comment by any blogger, and you're relatively new to the blog, as am I, compared to those that joine back in 2004/05
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Quoting ncstorm:


very little..models will flip back and forth


Are we still talking about the weather or getting a life?
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Quoting CybrTeddy:


ROFL!

I pay attention in biology even though it isn't weather.
Member Since: March 16, 2012 Posts: 123 Comments: 7887
Quoting ncstorm:


LOL...now that you have told me to get one, I will..I guess family and job dont count..what was I thinking??


After marriage and kids, my life ended....

Not really, just got a lot more hectic though.
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Quoting wxchaser97:

Technically we all have lives as we are all caring out the functions needed to live or else we wouldn't be able to blog.


ROFL!
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Quoting washingtonian115:
That means I'll have to cancel party plans.But a chance of that happening is little.


very little..models will flip back and forth
Member Since: August 19, 2006 Posts: 13 Comments: 13457
Quoting trHUrrIXC5MMX:


GET A LIFE!

Technically we all have lives as we are all caring out the functions needed to live or else we wouldn't be able to blog.
Member Since: March 16, 2012 Posts: 123 Comments: 7887
Quoting trHUrrIXC5MMX:


GET A LIFE!


LOL...now that you have told me to get one, I will..I guess family and job dont count..what was I thinking??
Member Since: August 19, 2006 Posts: 13 Comments: 13457
214

WHXX01 KWBC 210040

CHGHUR

TROPICAL CYCLONE GUIDANCE MESSAGE

NWS NATIONAL HURRICANE CENTER MIAMI FL

0040 UTC SUN OCT 21 2012



DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.

PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE

AND SUBTROPICAL CYCLONE INFORMATION.



ATLANTIC OBJECTIVE AIDS FOR



DISTURBANCE INVEST (AL992012) 20121021 0000 UTC



...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...

121021 0000 121021 1200 121022 0000 121022 1200



LAT LON LAT LON LAT LON LAT LON

BAMS 14.7N 73.7W 15.0N 75.7W 15.1N 77.7W 14.6N 79.8W

BAMD 14.7N 73.7W 15.0N 75.2W 15.3N 76.4W 15.5N 77.4W

BAMM 14.7N 73.7W 15.0N 75.4W 15.0N 76.8W 14.9N 78.2W

LBAR 14.7N 73.7W 15.3N 75.1W 16.0N 76.4W 16.5N 77.5W



...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...

121023 0000 121024 0000 121025 0000 121026 0000



LAT LON LAT LON LAT LON LAT LON

BAMS 14.0N 81.6W 12.0N 84.0W 10.6N 84.1W 11.1N 81.1W

BAMD 15.8N 78.1W 16.5N 78.8W 19.0N 78.9W 22.1N 79.3W

BAMM 14.8N 79.3W 14.3N 80.8W 14.5N 79.9W 18.5N 75.3W

LBAR 17.1N 78.3W 18.8N 79.5W 20.5N 79.6W 22.3N 78.1W



...INITIAL CONDITIONS...

LATCUR = 14.7N LONCUR = 73.7W DIRCUR = 280DEG SPDCUR = 6KT

LATM12 = 14.5N LONM12 = 72.5W DIRM12 = 283DEG SPDM12 = 7KT

LATM24 = 14.1N LONM24 = 70.5W

WNDCUR = 25KT RMAXWD = 120NM WNDM12 = 25KT

CENPRS = 1006MB OUTPRS = 1008MB OUTRAD = 180NM SDEPTH = S

RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM



$$

NNNN
Member Since: July 15, 2006 Posts: 165 Comments: 52262
Quoting Grothar:


Wie geht's? Ach, barb, sie necken mich um, ber meinen Akzent. lol

I wasn't aware the flooding was so bad. Is that the same system?


Armer Grothar, ich habe gesehen, wie schlecht es dir hier geht ;-) But you are fighting for your german roots, don't you?

In Germany we enjoy a very nice late summer weekend. All the rain remains to the west of us. For now. Next weekend sudden freezing temperatures and maybe snow in Germany is forecasted. I'll have some work to do to save my plants on the terrace; some of them still blossoming.

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Going to get in the 50's!:) tonight!!
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TROPICAL CYCLONE GUIDANCE MESSAGE
NWS NATIONAL HURRICANE CENTER MIAMI FL
0040 UTC SUN OCT 21 2012

DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.

ATLANTIC OBJECTIVE AIDS FOR

DISTURBANCE INVEST (AL902012) 20121021 0000 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
121021 0000 121021 1200 121022 0000 121022 1200

LAT LON LAT LON LAT LON LAT LON
BAMS 20.1N 47.9W 20.4N 49.0W 21.0N 50.4W 21.9N 51.9W
BAMD 20.1N 47.9W 21.3N 48.6W 22.0N 49.8W 22.6N 51.5W
BAMM 20.1N 47.9W 21.0N 48.7W 21.7N 50.0W 22.6N 51.6W
LBAR 20.1N 47.9W 20.8N 48.3W 21.4N 48.8W 22.1N 49.4W
SHIP 30KTS 32KTS 36KTS 42KTS
DSHP 30KTS 32KTS 36KTS 42KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
121023 0000 121024 0000 121025 0000 121026 0000

LAT LON LAT LON LAT LON LAT LON
BAMS 23.0N 53.2W 25.1N 55.2W 26.3N 56.6W 27.7N 57.7W
BAMD 23.4N 52.6W 25.5N 51.3W 28.6N 44.6W 32.7N 33.1W
BAMM 23.7N 52.9W 25.9N 53.7W 28.0N 50.9W 30.4N 42.0W
LBAR 23.2N 49.4W 27.1N 47.9W 31.6N 41.2W 35.6N 29.4W
SHIP 48KTS 53KTS 47KTS 40KTS
DSHP 48KTS 53KTS 47KTS 40KTS

...INITIAL CONDITIONS...
LATCUR = 20.1N LONCUR = 47.9W DIRCUR = 290DEG SPDCUR = 5KT
LATM12 = 19.8N LONM12 = 46.8W DIRM12 = 288DEG SPDM12 = 5KT
LATM24 = 19.3N LONM24 = 45.6W
WNDCUR = 30KT RMAXWD = 100NM WNDM12 = 30KT
CENPRS = 1012MB OUTPRS = 1014MB OUTRAD = 180NM SDEPTH = S
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM

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Quoting ncstorm:


I was talking about TA not you..


GET A LIFE!
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Quoting ncstorm:


I dont like the CMC..trying to be consistent which is saying a lot when mentioning that model..
That means I'll have to cancel party plans.But a chance of that happening is little.
Member Since: August 14, 2010 Posts: 10 Comments: 15710
Quoting trHUrrIXC5MMX:
no one said anything about the Epac...that's the hurricane to become in a couple of days I've been talking about

ZCZC MIATWOEP ALL
TTAA00 KNHC DDHHMM

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
500 PM PDT SAT OCT 20 2012

FOR THE EASTERN NORTH PACIFIC...EAST OF 140 DEGREES WEST LONGITUDE..

1. AN AREA OF DISTURBED WEATHER HAS FORMED A FEW HUNDRED MILES SOUTH OF
THE GULF OF TEHUANTEPEC. SLOW DEVELOPMENT OF THIS SYSTEM IS
POSSIBLE DURING THE NEXT COUPLE OF DAYS AS IT DRIFTS WESTWARD. THIS
SYSTEM HAS A LOW CHANCE...10 PERCENT...OF BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES WESTWARD AT 5 TO 10
MPH.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER BEVEN


I'm really interested in the track on this one. The M storm, can't remember its name dumped a very large moisture field over northern Mexico on its way out. Got a few inches of rain from it.
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well guys that's it for today

Im tired so bye. By the way Gro I hope you could help me with that...
see y'all
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Quoting trHUrrIXC5MMX:


I don't go to school...lol...graduated from High School...
done with that! I'll resume college in 5 years


I was talking about TA not you..
Member Since: August 19, 2006 Posts: 13 Comments: 13457
Wow I still have 9190 comments.Looks like my slow poke a__ needs to catch up.Lol.
Member Since: August 14, 2010 Posts: 10 Comments: 15710
I dont see the 18z ensembles spread for the GFS but here is the 12z





Member Since: August 19, 2006 Posts: 13 Comments: 13457
00z Best Track for 90L.

AL, 90, 2012102100, , BEST, 0, 201N, 479W, 30, 1012, DB
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Quoting barbamz:
Weekend hello from Germany.
Bad times right now for pilgrims in Lourdes (southern France) because of heavy flooding and it's not going to become better, because more rain is on the way. The grotto seems to be partly submerged.

CBS News: Pilgrims evacuated from flood-threatened Lourdes





Wie geht's? Ach, barb, sie necken mich um, über meinen Akzent. lol

I wasn't aware the flooding was so bad. Is that the same system?
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New blog.

Actually finished early for a change...
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Quoting ncstorm:


lol..he blogs from school too..


I don't go to school...lol...graduated from High School...
done with that! I'll resume college in 5 years
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Quoting washingtonian115:
Trough comming to the rescue be dammned if cmc was right..


I dont like the CMC..trying to be consistent which is saying a lot when mentioning that model..
Member Since: August 19, 2006 Posts: 13 Comments: 13457
Quoting Dakster:


Temperature or age?


no that nice there...although we know what he meant.
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Quoting TropicalAnalystwx13:

No excuse. I have 22,154 comments and I've been here since July 2010. ;)

Before anybody asks, yes, I have a life.

No you don't...
Quoting Tropicsweatherpr:
00z Best Track for 99L.

AL, 99, 2012102100, , BEST, 0, 147N, 737W, 25, 1006, DB

Pressure continues to lower, I think we should see a TD tomorrow.
Member Since: March 16, 2012 Posts: 123 Comments: 7887
Quoting trHUrrIXC5MMX:


how can you be so sure..???. today was my day off...
School time is nothing compared to the 12-15 hours of work I do
Im just 20 years old FYI


lol..he blogs from school too..
Member Since: August 19, 2006 Posts: 13 Comments: 13457
Quoting SFLWeatherman:
71 now!:)


Temperature or age?
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Quoting ncstorm:
JMA Model out to 144 hours
Trough comming to the rescue be dammned if cmc was right..
Member Since: August 14, 2010 Posts: 10 Comments: 15710
Quoting TropicalAnalystwx13:

I go to school the same amount of time you work and I go to bed at 11 at night.


I doubt that... My kids are not in school anywhere near as long as I work.
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JMA Model out to 144 hours
Member Since: August 19, 2006 Posts: 13 Comments: 13457
Quoting KoritheMan:


A German one. Duh.


Actually British, duh! lol.
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Quoting TropicalAnalystwx13:

I go to school the same amount of time you work.


how can you be so sure..???. today was my day off...
School time is nothing compared to the 12-15 hours of work I do
Im just 20 years old FYI
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00z Best Track for 99L.

AL, 99, 2012102100, , BEST, 0, 147N, 737W, 25, 1006, DB
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71 now!:)
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Quoting TropicalAnalystwx13:

I modified my comment right after posting it 'cause I knew you'd make that comment.

Know you so well. ;)


you're here for a long time everyday then...
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Quoting trHUrrIXC5MMX:


well, good back-up there.... Do you sleep every night?
I mean I work everyday...so...

I'll catch up...don't worry

I go to school the same amount of time you work and I go to bed at 11 at night.
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Quoting KoritheMan:


Yes but we all know you have no life, so...

I modified my comment right after posting it 'cause I knew you'd make that comment.

Know you so well. ;)
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Quoting TropicalAnalystwx13:

No excuse. I have 22,154 comments and I've been here since July 2010. ;)

Before anybody asks, yes, I have a life.


that was late...
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Quoting KoritheMan:


Yes but we all know you have no life, so...
LOL don`t be bad.
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Quoting KoritheMan:


Yes but we all know you have no life, so...


yes...I didn't want to use those terms but yeah that's what I meant.
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Weekend hello from Germany.
Bad times right now for pilgrims in Lourdes (southern France) because of heavy flooding and it's not going to become better, because more rain is on the way. The grotto seems to be partly submerged.

CBS News: Pilgrims evacuated from flood-threatened Lourdes



Edit: Report on BBC News
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Quoting TropicalAnalystwx13:

No excuse. I have 22,154 comments and I've been here since June 2010. ;)


well, good back-up there.... Do you sleep every night?
I mean I work everyday...so...

I'll catch up...don't worry
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Quoting TropicalAnalystwx13:

No excuse. I have 22,154 comments and I've been here since June 2010. ;)


Yes but we all know you have no life, so...
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Quoting trHUrrIXC5MMX:


you're here since '05...I been coming here since 2006 but made an account last year otherwise I'll be in the 15,000s or more

No excuse. I have 22,154 comments and I've been here since July 2010. ;)

Before anybody asks, yes, I have a life.
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Member Since: October 9, 2008 Posts: 0 Comments: 8242
Quoting Grothar:


OK, what type of accent do I have then?


Ummm... Never mind. Too easy... I give you a pass on that on Gro!

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Quoting CybrTeddy:


I'm at 19,376, you need to catch up. ;)


you're here since '05...I been coming here since 2006 but made an account last year otherwise I'll be in the 15,000s or more
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Quoting Grothar:


OK, what type of accent do I have then?


A German one. Duh.
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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.