93L slow to develop, but bringing heavy rains to Haiti

By: Dr. Jeff Masters , 1:50 PM GMT on June 22, 2010

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A modest region of intense thunderstorms (Invest 93L) is over the central Caribbean, a few hundred miles south of Hispaniola. This disturbance has the best chance to become Tropical Storm Alex of any system we've seen so far this year. We don't have any buoys near 93L, but pressures at the ground stations surrounding the storm are not falling. A pass of the ASCAT satellite over the Central Caribbean at 9:45 pm EDT last night revealed a modest wind shift associated with 93L, but nothing at all close to a surface circulation. Top surface winds seen by ASCAT were 15 - 20 mph. Water vapor satellite loops show that 93L is embedded in a large region of moist air. The atmosphere over the Caribbean has moistened over the past day, which should aid development of 93L. Wind shear is a low 5 - 10 knots. The high wind shear associated with the strong winds of the subtropical jet stream are over the northern Caribbean, too far north to interfere with development, but close enough to provide good upper-level outflow for the storm. Visible satellite loops show high level cirrus clouds streaming away from 93L to the northeast, evidence of the upper-level outflow channel that is developing to the storm's north. Sea Surface Temperatures are plenty warm, a record 29 - 30°C. The Madden-Julian oscillation (MJO) currently favors upward motion over the Caribbean, which will act to increase the chances of tropical storm formation this week. The Madden-Julian oscillation is a pattern of enhanced rainfall that travels along the Equator from west to east. The pattern has a wet phase with large-scale rising air and enhanced thunderstorm activity, followed by a dry phase with large-scale sinking air and suppressed thunderstorm activity. Each cycle lasts approximately 30 - 60 days. When the Madden-Julian oscillation is in its wet phase over a hurricane-prone region, the chances for tropical storm activity are greatly increased. The main negative for 93L continues to be lack of spin. The University of Wisconsin 850 mb relative vorticity analysis is showing that spin at 850 mb (roughly 5,000 feet in altitude) has increased over the past day, but 93L needs to acquire additional spin before it can grow more organized. I speculate that it is this lack of spin that contributed to the loss of much of 93L's heavy thunderstorm activity last night. The storm is now going through a cycle where it is building another respectable mass of heavy thunderstorms, and the increased inflow of low-level air that will feed these thunderstorms will likely enhance 93L's spin today. The Hurricane Hunters are on call to investigate 93L on Wednesday afternoon.


Figure 1. Morning visible satellite image of the central Caribbean disturbance 93L.

Forecast for 93L
NHC is giving 93L a 40% chance of developing into a tropical depression by Thursday morning, which is a reasonable forecast. Given the storm's current lack of spin and relatively modest amount of heavy thunderstorms, the earliest I'd expect 93L to become a tropical depression would be Wednesday afternoon, with Thursday more likely. Wind shear is expected to be low, less than 10 knots, over the central and western Caribbean this week. Water temperatures will be warm, dry air absent, and the MJO favorable. I don't see any major impediments to the storm becoming a tropical depression by Thursday, and it is a bit of a surprise to me that the computer models have been reluctant to develop 93L. The GFS, NOGAPS, and UKMET models do not develop 93L, and the ECMWF model doesn't develop 93L until after it crosses the Yucatan Peninsula and enters the Gulf of Mexico in a about a week. The current (2am EDT) run of the GFDL model predicts 93L will be a weak tropical storm in the Gulf of Mexico in five days; its previous run had 93L as a major hurricane in the Gulf. Given all this model reluctance and the current disorganization of 93L, I give the storm a low (less than 20% chance) of becoming a hurricane in the Caribbean. Expect 93L to bring flooding rains of 3 - 6 inches to Jamaica, eastern Cuba, and southwestern Haiti today through Wednesday. These rains will spread to the Cayman Islands and central Cuba by Thursday, and western Cuba and Mexico's Yucatan Peninsula on Friday. The current run of the SHIPS model has 93L slowing down late this week to a forward speed of just 6 knots (7 mph) from its current speed of about 10 mph, in response to a weakening in the steering currents. A trough of low pressure is expected to swing down over the Eastern U.S. early next week. If this trough is strong enough and 93L develops significantly, the storm could get pulled northwards and make landfall along the northern Gulf of Mexico coast in the oil spill region. This is the solution of the Canadian GEM model. If 93L stays weak and/or the trough is not so strong, the storm would get pushed west-northwestwards towards the Texas coast. This is the solution of the ECMWF model. The amount of wind shear in the Gulf of Mexico next week is highly uncertain. There is currently a band of high shear near 30 knots over the Gulf, and some of the models predict this shear will remain over the Gulf over the next 7 - 10 days. However, other models predict that this band of high shear will retreat northwards and leave the Gulf nearly shear-free. The long-term fate of 93L remains very murky. My main concerns at this point are the potential for 3 - 6 inches of rain in Haiti over the next two days, and the possibility 93L could become a hurricane in the Gulf of Mexico next week.

Elsewhere in the tropics
None of the reliable computer models is calling for tropical cyclone formation elsewhere in the Atlantic over the next seven days.

Floods in China and Burma kill over 250
The deadliest and most destructive weather-related disaster on the planet so far this year is occurring in southern China and northern Burma, where a week of heavy rains has caused flooding that has claimed over 250 lives. The heavy rains and floods ravaging 10 southern Chinese provinces had killed 199 and left 123 missing as of 11:00 a.m. Tuesday, a Ministry of Civil Affairs statement said. Damage is estimated at $6.2 billion. Floods and landslides in neighboring areas of Myanmar (Burma) have claimed at least 63 lives in the past week.


Figure 2. Paramilitary policemen help evacuate residents from Wanjia village of Fuzhou City, East China's Jiangxi province, June 22, 2010. Days of heavy rain burst the Changkai Dike of Fu River on June 21, threatening the lives of 145,000 local people. Local authorities have ordered immediate evacuation, and the army and paramilitary police have begun conducting rescue operations. Image credit: Xinhua.

Wind and ocean current forecast for the BP oil disaster
Southeast to east winds less than 10 knots will blow in the northern Gulf of Mexico today through Saturday, according to the latest marine forecast from NOAA. The resulting weak ocean currents should cause little motion of the oil slick, according to the latest trajectory forecasts from NOAA and the State of Louisiana. The long range outlook is uncertain, and will depend upon what 93L does.

Resources for the BP oil disaster
My post, What a hurricane would do the Deepwater Horizon oil spill
My post on the Southwest Florida "Forbidden Zone" where surface oil will rarely go
My post on what oil might do to a hurricane
NOAA's interactive mapping tool allows one to overlay wind and ocean current forecasts, oil locations, etc.
Gulf Oil Blog from the UGA Department of Marine Sciences
Oil Spill Academic Task Force
University of South Florida Ocean Circulation Group oil spill forecasts
ROFFS Deepwater Horizon page
Synthetic Aperture Radar (SAR) imagery from the University of Miami

"Hurricane Haven" airing again this afternoon
Tune into another airing of my live Internet radio show, "Hurricane Haven", at 4pm EDT today. Listeners will be able to call in and ask questions. The call in number is 415-983-2634, or you can post a question in the comments area on my blog. You can also email the questions to me today before the show: jmasters@wunderground.com. Be sure to include "Hurricane Haven question" in the subject line. Some topics I'll cover today on the show:

1) The latest on 93L
2) Which model is the most reliable?

Today's show will be 30 - 40 minutes, and you can tune in at http://www.wunderground.com/wxradio/wubroadcast.h tml. The show will be recorded and stored as a podcast.

Jeff Masters

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2995. xcool
:0
Member Since: September 26, 2009 Posts: 2 Comments: 15648
Hey there everybody. Looks like 93L is about done having the rug pulled out from underneath him. So now we will wait and see whether he is able to stand up for just a minute, or if he will fall flat on his face.
Photobucket
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that is sobering keeper. kinda reminds me of that steven segall movie about the oil tycoon. "how much money is enough?"
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Quoting Hurricanes12:
ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 AM EDT WED JUN 23 2010

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

1. SHOWERS AND A FEW THUNDERSTORMS ASSOCIATED WITH A TROPICAL WAVE OVER
THE CENTRAL CARIBBEAN SEA CONTINUE TO PRODUCE HEAVY RAINFALL ACROSS
PORTIONS OF THE DOMINICAN REPUBLIC...HAITI...AND THE ADJACENT
WATERS. THIS SYSTEM HAS NOT BECOME ANY BETTER ORGANIZED...BUT
UPPER-LEVEL WINDS APPEAR CONDUCIVE FOR SOME SLOW DEVELOPMENT AS IT
MOVES WESTWARD AROUND 10 MPH INTO THE WESTERN CARIBBEAN OVER THE
NEXT DAY OR TWO. IN ADDITION...HEAVY RAINFALL COULD AFFECT
PORTIONS OF JAMAICA AND CUBA OVER THE NEXT COUPLE OF DAYS. THERE
IS A LOW CHANCE...20 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS.

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

$$
FORECASTER BERG
NNNN


I expected that.
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Member Since: July 3, 2007 Posts: 0 Comments: 524
2989. KEEPEROFTHEGATE (Mod)





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test...

can really see the mlc moving nw earlier this evening...i love the nexsat for some reason...

and that oil rain video is pretty sickening...
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plenty of moisture, no shear, sounds like show time.
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Quoting Drakoen:
HWRF 00Z:




That is exactly over the Deepwater Horizon.
Member Since: Posts: Comments:
2983. watchingnva
looks like something trying to fire there in the center, could it be the infamous coc?
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2984. xcool
93l get ready kaboom
Member Since: September 26, 2009 Posts: 2 Comments: 15648
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Quoting xcool:
MATT HOOK ME UP SHI


hahahaha yeah
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2979. xcool
NOT YET
Member Since: September 26, 2009 Posts: 2 Comments: 15648
2977. xcool
YEP .ROB
Member Since: September 26, 2009 Posts: 2 Comments: 15648
is it too early to panic/book hotel rooms away from the coast?? haha
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2974. KEEPEROFTHEGATE (Mod)
REMAINS YELLOW 20 PERCENT
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2973. xcool
N
Member Since: September 26, 2009 Posts: 2 Comments: 15648
ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 AM EDT WED JUN 23 2010

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

1. SHOWERS AND A FEW THUNDERSTORMS ASSOCIATED WITH A TROPICAL WAVE OVER
THE CENTRAL CARIBBEAN SEA CONTINUE TO PRODUCE HEAVY RAINFALL ACROSS
PORTIONS OF THE DOMINICAN REPUBLIC...HAITI...AND THE ADJACENT
WATERS. THIS SYSTEM HAS NOT BECOME ANY BETTER ORGANIZED...BUT
UPPER-LEVEL WINDS APPEAR CONDUCIVE FOR SOME SLOW DEVELOPMENT AS IT
MOVES WESTWARD AROUND 10 MPH INTO THE WESTERN CARIBBEAN OVER THE
NEXT DAY OR TWO. IN ADDITION...HEAVY RAINFALL COULD AFFECT
PORTIONS OF JAMAICA AND CUBA OVER THE NEXT COUPLE OF DAYS. THERE
IS A LOW CHANCE...20 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS.

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

$$
FORECASTER BERG
NNNN
Member Since: Posts: Comments:
2970. xcool
ILOVE pizza I MARRED PIZZA JUST JOKE
Member Since: September 26, 2009 Posts: 2 Comments: 15648
2969. JLPR2
Quoting btwntx08:

lmao im thinkin pizza for tomorrow mmmmmmm unfourntely we dont have papa johns in the city limits it like 25 miles away in another town....other pizza i like is pizza hut and little ceaears


I have so many pizza places in my area that it is ridiculous and you dont want to know how many Burger kings XD LOL!
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2967. xcool
Member Since: September 26, 2009 Posts: 2 Comments: 15648



just my tired opinion...lol...the yellow circle is a lil small...somewhere just to the east/southeast of Jamaica...lol

night guys. check back in the a.m.
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2964. EricSFL
Things are pretty bad here in the Miami metro area jobwise also.
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2963. xcool
HWRF imo imo not good
Member Since: September 26, 2009 Posts: 2 Comments: 15648
what happened, i put the url in and nothing???
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Hey all how is everyone so is anything hitting florida in the next two weeks I am located south east florida
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Quoting btwntx08:

means its a cat 2 headed towards ms/al


how reliable is that model? Yesterday all the models had it going to TX. What did i miss?
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Quoting btwntx08:

means its a cat 2 headed towards ms/al


gah dont freaking say that - this thing isnt even a depression yet
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i believe she is gonna get fired up
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2957. xcool
MATT HOOK ME UP SHI
Member Since: September 26, 2009 Posts: 2 Comments: 15648
2956. xcool
LOL OOOOO papa johns YES SIR CAN I HAVE PIZZAS NOW
Member Since: September 26, 2009 Posts: 2 Comments: 15648
2955. JLPR2
Quoting tornadodude:


haha right on!!

Well besides dodging the summer heat here, just working!

started a new job at Papa Johns delivering pizzas


Ah nice, getting a job here is almost impossible, but then again I didn't try to get one, I'll have to get one eventually, the bank isn't eternal -.-
XD
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2952. JLPR2
Quoting xcool:
ATTENTION...NATIONAL HURRICANE CENTER

NCEP COUPLED GFDL HURRICANE MODEL FORECAST MADE FOR

TROPICAL DEPRESSION INVEST 93L

INITIAL TIME 0Z JUN 23

DISCLAIMER ... THIS INFORMATION IS PROVIDED AS GUIDANCE. IT
REQUIRES INTERPRETATION BY HURRICANE SPECIALISTS AND SHOULD
NOT BE CONSIDERED AS A FINAL PRODUCT. PLEASE SEE THE TPC/NHC
OFFICIAL FORECAST.


FORECAST STORM POSITION

HOUR LATITUDE LONGITUDE HEADING/SPEED(KT)

0 15.4 75.2 280./12.0
6 15.8 76.5 288./13.0
12 16.0 77.2 282./ 6.7
18 16.5 78.1 302./10.4
24 16.8 78.8 292./ 7.1
30 17.4 79.5 305./ 9.4
36 17.9 80.6 293./11.1
42 18.5 81.5 308./10.8
48 18.6 82.3 275./ 7.8
54 19.4 83.6 302./14.6
60 19.9 84.5 300./ 9.9
66 20.7 85.7 304./13.7
72 21.0 87.0 282./12.7
78 21.4 88.3 285./12.2
84 21.9 89.2 302./10.3
90 22.2 89.6 303./ 4.9
96 22.6 90.0 321./ 5.2
102 23.4 90.5 326./ 9.7
108 24.9 90.6 356./14.5
114 26.3 90.6 1./14.0
120 27.5 90.3 13./12.7
126 28.9 90.0 12./13.9



Again with he TD Invest stuff LOL!
that's just confusing, they shouldn't do that, they did that with 92L too
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Quoting Drakoen:
HWRF 00Z:



What is that Drak? And what does that mean? Please explain!
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2950. Drakoen
I'm out for the night
Member Since: October 28, 2006 Posts: 57 Comments: 30181


Uploaded with ImageShack.us

just my tired opinion...lol

night guys.
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Quoting JLPR2:


All's good, sighing every time I see the calendar since my university starts the 5th, got to finish my second semester. :S
But besides taking classes in the middle of summer, yeah, all's good LOL!

How about over there?


haha right on!!

Well besides dodging the summer heat here, just working!

started a new job at Papa Johns delivering pizzas
Member Since: Posts: Comments:
2946. xcool
ATTENTION...NATIONAL HURRICANE CENTER

NCEP COUPLED GFDL HURRICANE MODEL FORECAST MADE FOR

TROPICAL DEPRESSION INVEST 93L

INITIAL TIME 0Z JUN 23

DISCLAIMER ... THIS INFORMATION IS PROVIDED AS GUIDANCE. IT
REQUIRES INTERPRETATION BY HURRICANE SPECIALISTS AND SHOULD
NOT BE CONSIDERED AS A FINAL PRODUCT. PLEASE SEE THE TPC/NHC
OFFICIAL FORECAST.


FORECAST STORM POSITION

HOUR LATITUDE LONGITUDE HEADING/SPEED(KT)

0 15.4 75.2 280./12.0
6 15.8 76.5 288./13.0
12 16.0 77.2 282./ 6.7
18 16.5 78.1 302./10.4
24 16.8 78.8 292./ 7.1
30 17.4 79.5 305./ 9.4
36 17.9 80.6 293./11.1
42 18.5 81.5 308./10.8
48 18.6 82.3 275./ 7.8
54 19.4 83.6 302./14.6
60 19.9 84.5 300./ 9.9
66 20.7 85.7 304./13.7
72 21.0 87.0 282./12.7
78 21.4 88.3 285./12.2
84 21.9 89.2 302./10.3
90 22.2 89.6 303./ 4.9
96 22.6 90.0 321./ 5.2
102 23.4 90.5 326./ 9.7
108 24.9 90.6 356./14.5
114 26.3 90.6 1./14.0
120 27.5 90.3 13./12.7
126 28.9 90.0 12./13.9

Member Since: September 26, 2009 Posts: 2 Comments: 15648

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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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