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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Aquak, did you catch my comment about the rain dance?
Loop
cmc 144h
gfdl 126h
ngp 144h
From what I've read, sheer may be a problem.
Arlene just as it became a TD:
Then a TS:
I'm gonna have to say C (50%), but I wouldn't be surprised if 94L will be at 60%.
But with the anticyclone over it, it can fend off the high shear right?
I say its a bit more east than what you have it now
Not much showing up.
There are some BIG cumulus all around, and the visibility is great.
Mountainous cloud over the Andes on the Paria Peninsula visible from here. About 15 miles..
Fantastic evening>
CHEERS!
There's no guarantee that it will be. If it's going to develop, I would guess it will be within the next 48-60 hours before wind shear picks up again due to the upper trough over the Gulf of Mexico.
Nearly every June system is.
We used 'pre-93L' for a few days, then 'pre-94L' for a few days.... Are we really trying 'pre-Arelene' now? :P
Invest94
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)
Dynamic Models (More sophisticated models)
Early Model Wind Forecasts
all displaced to the south, in fact I believe most of is still attached to the monsoon trough
The GFS shear forecast only increases the shear for a short time, it has it low again in the caribbean about 4-5 days out, so if 94L is still there, which it may not be, it could have one more chance then.
I think it will go to about 50% at 8pm but the D-Max tonight will probably bring it up to a red 60% or 70% by 8am tomorrow morning, plus I think the conditions may get slightly better for development over the next 12-24 hours. Anyone agree with me?
agreed...not south/sse of jamaica like some might wanna believe ... mid to upper level there...
Looks may be deceiving, on rainbow the COC appears to be directly south of Jamacia, but Rainbow satellite imagery picks up circulations at both the mid and lower levels.
Hey fellow Richmonder, how's it going?
Gulf Of Mexico - Rainbow Loop
Viewing: 601 - 651
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