Caribbean disturbance 94L dumping heavy rains on Jamaica
A large, wet, and disorganized tropical disturbance (Invest 94L) continues to spread heavy rain to the Central Caribbean near Jamaica. Rain has fallen continuously at Jamaica's Kingston Norman Manley Airport since midnight, with 1.89" having fallen from midnight to noon local time. Sustained winds of 24 mph also affected Kingston between 7am and 8am this morning. Satellite-estimated rainfall amounts of 1.4" per hour occurred in ocean regions 100 miles to the southeast of Kingston this morning, and heavy rains of up to 1/2" per hour are probably affecting portions of Jamaica early this afternoon, judging by the recent increase in heavy thunderstorm activity seen on visible satellite loops. This imagery also shows a slow increase in organization of 94L in recent hours, with spiral bands beginning to develop to the southeast of the center. There is a broad, poorly-defined circulation apparent that is not well enough defined to make 94L a tropical depression. Water vapor satellite loops show a region of dry air on the west side of 94L, and this dry air is interfering with the storm's organization. However, upper air balloon soundings from Kingston and the Cayman Islands taken at 8am EDT this morning show much moister air at mid levels of the atmosphere compared to Saturday (2% humidity at 500 mb on Saturday, compared to 49% this morning at Grand Cayman), and 94L appears to be gradually overcoming its dry air issues. Wind shear remains in the moderate range, 15 - 20 knots, and is predicted by the SHIPS model to remain below 20 knots through Tuesday morning. Water temperatures in the Central Caribbean are about 1°C above average, 28 - 28.5°C, which is 2°C above the threshold needed to support development of a tropical storm.

Figure 1. Rainfall rates of up to 1.4" per hour (pink colors) were estimated by the F-15 satellite for 94L at 6:02am EDT Jun 5, 2011.
Since 94L is so large and is battling dry air, it is taking its sweet time to develop, and today's mission by the Hurricane Hunters has been cancelled. A new mission is scheduled for Monday afternoon at 2pm EDT. This morning's 06Z model runs are pretty unimpressed with 94L, with most of them showing little or no development. At 2pm EDT on Sunday, NHC gave the disturbance a 40% of developing into a tropical depression by Tuesday. If 94L stays to the south, its chances of development are greater, since a band of very high wind shear of 30 - 50 knots lies over Cuba and the southern Bahama Islands. The disturbance is expected to meander slowly westward or northward over the next two days, with Jamaica and southeastern Cuba being the primary targets for very heavy rains of 4 - 8 inches through Tuesday. Haiti and Central Cuba can expect somewhat lesser rains of 3 - 6 inches. If 94L does develop into a tropical depression and moves northwards over Cuba by Wednesday, I don't see the storm attaining hurricane strength, due to the high wind shear. The primary threat from 94L will be very heavy rains, capable of causing life-threatening flash flooding.

Figure 2. Afternoon satellite image of the Central Caribbean disturbance 94L.
Jeff Masters
Reader Comments
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94L has much more of a chance than 91L ever did. Still not entirely convinced though, I would say we'll get another 40%.
A broad area of low pressure, labeled Invest 94-L, was located about 175 miles to the south of Grand Cayman. The heaviest convection associated with 94-L was separated both to the west and to the east from the center of circulation which is the low pressure system. Environmental conditions are expected to be favorable for development of this system from today through about Tuesday or Wednesday. After that, environmental conditions will become unfavorable and whatever becomes of Invest 94-L will become highly sheared.
Given the better organized structure that is clearly visible on satellite imagery, the deep thunderstorm activity that is occurring and the fact that it is currently under quite favorable environmental conditions, I do think Invest 94-L will go ahead and try to develop into a tropical depression during the day today or tonight and then very possibly tropical storm Arlene as we get into Tuesday or Wednesday. A reconnaissance flight is scheduled to investigate 94-L this afternoon to determine whether it is indeed a tropical depression.
I'll go with 40% on 94L. Time is running out on it...soon.
I would not mind rain here, winds below forty and lotsa rain. I think that's all we want.
Crown does excellent meteorological synopsis, but his hopefulness tends to be underlying in his opinions.
Enjoying the lower gas prices- I too, do not wanna see anything bigger than a TD enter the Gulf.
It is now raining, very bleak and heavily overcast where I am and I am sure it is worse in parishes such as St. Thomas and Portland. This trend could cause serious damages to some parishes especially loss to farmers and the economy. So far I have received only one unconfirmed report of a fisherman drowning at sea yesterday. We need the water but not the flooding which is now likely.
See you later.
I see that 94L is holding on as I and others anticipated and the models tracks are once again starting to, as aquak calls it looks like a spider. All the local mets are now calling attention to this feature with a increase of rain chance in CFL for this weekend. One could only hope. Watch out today for tornadoes in Central/Eastern Montana and Eastern Wisconsin/North-central Michigan. Conditions will be ripe for large tornadoes this afternoon and evening.
A Glorious One, here.
I see that "Annoying Arlene" (just to give it a name) is still causing Confusion.
I think that DMin and Shear and everything else later today might just be too much for her. It was fun, but Good Riddance!
Hi Ike!
Puerto Rico is under a flash flood watch until Tuesday because of the long tail from 94L that is moving north.
About 94L, I am on the 40% at 8 AM TWO camp too.
Hey.....
Yeah! I realise you have had a really bad dry.
I hope you get some good rains soon.
Heard from my sister who is near Tuscon Arizona this morning, it's bad there too, and burning.
Not good at all....
Somewhere in the sahara:
(5:50 am EST)
1050 GMT on 06/06/2011:
Unit of Measure: Time Zone:
Click on the graph icon in the table below to see a time series plot of the last five days of that observation.
5-day plot - Wind Direction Wind Direction (WDIR): WSW ( 240 deg true )
5-day plot - Wind Speed Wind Speed (WSPD): 5.8 kts
5-day plot - Wind Gust Wind Gust (GST): 7.8 kts
5-day plot - Wave Height Wave Height (WVHT): 4.3 ft
5-day plot - Dominant Wave Period Dominant Wave Period (DPD): 8 sec
5-day plot - Average Period Average Period (APD): 5.9 sec
5-day plot - Mean Wave Direction Mean Wave Direction (MWD): NE ( 43 deg true )
5-day plot - Atmospheric Pressure Atmospheric Pressure (PRES): 29.71 in
5-day plot - Air Temperature Air Temperature (ATMP): 80.6 °F
5-day plot - Water Temperature Water Temperature (WTMP): 82.6 °F
5-day plot - Dew Point Dew Point (DEWP): 79.7 °F
5-day plot - Heat Index Heat Index (HEAT): 88.7 °
Bring Coffee.
On it!
Good!
And at about 8;30 we will expect eggs, pancakes, sausages, bacon and stuff because we have to mix 10 cu.yds of concrete this morning.
So get out of that dress and get moving!
Morning everyone... not sure I was ready for that image....
Oh my gosh!In Poland we also have drought,yesterday they was 120 forest fires,and I don't see the end of this in next days...
Thanks.
Interesting drop there...
Leaving it behind. Things certainly aren't getting better for 94L.
Dude, it's restoring it's convecton.
I don't think so.
I think the odds of this becoming a TS are low.
The latest GFS run has been consistent on a storm off the SE Atlantic coast for a while now..around the 16th..
The worst of it went south of me. Got .12 inches of rain...total for the weekend.
By the time it hit Spring, it had died down a little. Lots of straight line gusts (some branches down, etc) and rain for about 30 minutes which I am very grateful for. We did not lose power though we did earlier in the day when the storms were well away from us.
I would estimate 1/4 inch of rain. After yesterdays 105 degree high it was a welcome relief.
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT MON JUN 6 2011
FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...
A LARGE BUT DISORGANIZED AREA OF SHOWERS AND THUNDERSTORMS
ASSOCIATED WITH A BROAD LOW PRESSURE SYSTEM CONTINUES OVER MUCH OF
THE CENTRAL AND WESTERN CARIBBEAN SEA. THE AREA OF LOWEST PRESSURE
IS LOCATED ABOUT 130 MILES SOUTH OF GRAND CAYMAN AND REMAINS
SEPARATED FROM THE STRONGEST THUNDERSTORM ACTIVITY. HOWEVER...SOME
DEVELOPMENT OF THIS SYSTEM IS POSSIBLE DURING THE NEXT DAY OR SO
BEFORE UPPER-LEVEL WINDS BECOME UNFAVORABLE. THERE IS A MEDIUM
CHANCE...40 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE
DURING THE NEXT 48 HOURS. AN AIR FORCE RESERVE HURRICANE HUNTER
AIRCRAFT MISSION HAS BEEN RESCHEDULED TO INVESTIGATE THE SYSTEM
TOMORROW...IF NECESSARY. REGARDLESS OF DEVELOPMENT...HEAVY RAINS
COULD CAUSE FLASH FLOODS AND MUD SLIDES OVER PORTIONS OF HAITI AND
JAMAICA AS THE SYSTEM MOVES SLOWLY TOWARD THE NORTHWEST OR NORTH
OVER THE NEXT COUPLE OF DAYS.
ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.
Sorry about that.
Kind of puts a damper on an otherwise nice day.
:):))
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