Caribbean disturbance 94L dumping heavy rains on Jamaica

By: Dr. Jeff Masters , 4:44 PM GMT on June 05, 2011

Share this Blog
8
+

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

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 647 - 597

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39Blog Index

Quoting MiamiHurricanes09:
You mixed your numbers up, lol. Winds are 61 knots (not at the surface; 10 meters above it) and the pressure was 989mb in 126 hours.


My bad, lol...totally looks like an "8" and a "5". Thanks for clarifying...10 meters shouldn't make a whole lot of difference though, that's only like 33 feet.
Member Since: Posts: Comments:
Quoting watchingnva:


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?
Member Since: Posts: Comments:
Quoting eyestalker:

80-something knots and 959 mb? Definitely not a TS.

??huh?? i just saw a loop of it at hr 126 on the 12z gfdl and it was 61 kts and pressure 989 mb show me where did u find it??
Member Since: Posts: Comments:
Quoting eyestalker:

80-something knots and 959 mb? Definitely not a TS.
You mixed your numbers up, lol. Winds are 61 knots (not at the surface; 10 meters above it) and the pressure was 989mb in 126 hours.

Member Since: Posts: Comments:
Quoting Levi32:


Nearly every June system is.

true, Cindy was pretty ugly too especially at first, Alberto and Barry looked horrible....Alex was an exception though.
Member Since: Posts: Comments:
Link invest94L VIDEO
Member Since: April 2, 2011 Posts: 0 Comments: 2278
Quoting Levi32:


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.
So it will be primarily be a rainmaker for whoever gets it?
Member Since: Posts: Comments:
The GFS shear forecast has the shear very high in the GoM in 4-5 days, would need to be a strong system to cope with that and get near the US as a decent storm.
Member Since: Posts: Comments:
Quoting tropicfreak:


But with the anticyclone over it, it can fend off the high shear right?

80-90% of it
Member Since: Posts: Comments:
Quoting Levi32:
Low-level center appears to be about here:



Loop


agreed...not south/sse of jamaica like some might wanna believe ... mid to upper level there...
Member Since: Posts: Comments:
Quoting stormpetrol:
60% at 8pm I think if this trend with 94L continues


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?
Member Since: Posts: Comments:
Quoting Levi32:


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.


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.
Member Since: Posts: Comments:
94L has also started to ventilate well too, what a huge system!
Member Since: April 29, 2007 Posts: 0 Comments: 7982
Quoting TxHurricanedude11:

at the end of the run I only saw a strong ts on the gfdl not quite hurricane

80-something knots and 959 mb? Definitely not a TS.
Member Since: Posts: Comments:
91E has a nice circulation but look at the convection

all displaced to the south, in fact I believe most of is still attached to the monsoon trough
Member Since: Posts: Comments:
Member Since: Posts: Comments:
18z Early Cycle NHC model tracks
Invest94
Statistical/Simple Models (CLIPER,BAMs,LBAR,other Statistical Models)




Dynamic Models (More sophisticated models)


Early Model Wind Forecasts
Member Since: July 3, 2005 Posts: 426 Comments: 129089
Quoting eyestalker:

Shear is fairly high in the Gulf right now but if (pre-Arlene) can maintain its upper-level high it will ameliorate the shear by the standard 80-90%. Dry air would seem to be the only problem.


We used 'pre-93L' for a few days, then 'pre-94L' for a few days.... Are we really trying 'pre-Arelene' now? :P
Member Since: Posts: Comments:
Quoting eyestalker:

Funny how that one was lopsided to the east as well...


Nearly every June system is.
Member Since: November 24, 2005 Posts: 635 Comments: 26681
Quoting scott39:
When are you looking for 94L to be a TD?


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.
Member Since: November 24, 2005 Posts: 635 Comments: 26681
Just back in to check some maps, as I am hearing loud thunder close to me in the east.
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!
Member Since: Posts: Comments:
Quoting eyestalker:
CMC and GFDL models still predict hurricane Arlene; NOGAPS predicts TS Arlene making landfall in the Florida Panhandle.

at the end of the run I only saw a strong ts on the gfdl not quite hurricane
Member Since: Posts: Comments:
Quoting NICycloneChaser:


That's what a storm approaching tropical depression status looks like.
And that's not what we're seeing with 94L.lol.
Member Since: Posts: Comments:
Quoting Stormchaser2007:


Arlene just as it became a TD:


Then a TS:




Funny how that one was lopsided to the east as well...
Member Since: Posts: Comments:
Quoting Levi32:
It will be interesting to see if this buoy bottoms out in the diurnal valley lower than the previous cycle:

why is the minimum pressure over water during the day time if the maximum convection occurs during nighttime?
Member Since: Posts: Comments:
Quoting Levi32:
Low-level center appears to be about here:



Loop


I say its a bit more east than what you have it now
Member Since: June 13, 2009 Posts: 2 Comments: 12324
Quoting IKE:

From what I've read, sheer may be a problem.

Shear is fairly high in the Gulf right now but if (pre-Arlene) can maintain its upper-level high it will ameliorate the shear by the standard 80-90%. Dry air would seem to be the only problem.
Member Since: Posts: Comments:
Levi, I like your placement. I think I'd guess a bit NE of there, but not by much. We are clearly looking at the same features.
Member Since: Posts: Comments:
619. IKE

Member Since: Posts: Comments:
Another wishcaster for SFL landfall of TS Arlene the lawn looks like a nuke exploded on it! Rain, yes please!
Member Since: Posts: Comments:
Quoting IKE:

From what I've read, sheer may be a problem.


But with the anticyclone over it, it can fend off the high shear right?
Member Since: Posts: Comments:
Quoting sammywammybamy:
POLL:

What is the Percantage on the Next Two for 94L

A) 30%
B) 40%
C) 50%
D) 60%
E) 70%
F) Shower Curtains!


~~~~~~~~~~~~~~~~~~~~~~~~

POLL RESULTS (So Far)

-------------
B C D E F
B C D E F
B C D 0 F
0 C D
0 0 D

3 4 5 2 3

60% is now Leading in the Poll

I'm gonna have to say C (50%), but I wouldn't be surprised if 94L will be at 60%.
Member Since: Posts: Comments:
Quoting eyestalker:
I would expect 91E to develop first as in 2005 we had Adrian before Arlene. Quite frankly both systems look like somewhat replicates of their last namesake lol.


Arlene just as it became a TD:


Then a TS:



Member Since: Posts: Comments:
CMC and GFDL models still predict hurricane Arlene; NOGAPS predicts TS Arlene making landfall in the Florida Panhandle.
Member Since: Posts: Comments:
Quoting Levi32:
Low-level center appears to be about here:



Loop
When are you looking for 94L to be a TD?
Member Since: Posts: Comments:
612. JRRP
Member Since: Posts: Comments:
Maybe we'll see the AEMN (GFS Ensemble Mean) and AVNO (NCEP Aviation Model) jump on board again overnight. Still some big globals not interested.
Member Since: January 30, 2010 Posts: 0 Comments: 3259
610. IKE

Quoting scott39:
Man...What a difference of 12 hours can make. Do you know what the shear and dry air is suppossed to look like in the GOM this week?
From what I've read, sheer may be a problem.
Member Since: Posts: Comments:
94L Caribbean - Water Vapor Loop
Member Since: July 3, 2005 Posts: 426 Comments: 129089
Quoting Levi32:
Low-level center appears to be about here:



Loop

Which means it's still quite a bit lopsided to the east, but it's not as terribly disorganized as it was the last few days and if we see an enhancement of convection near this COC we should have a depression tomorrow.
Member Since: Posts: Comments:
Its been awhile since three or four of these took a storm pretty close to the same area?

cmc 144h


gfdl 126h


ngp 144h


Member Since: Posts: Comments:
I would expect 91E to develop first as in 2005 we had Adrian before Arlene. Quite frankly both systems look like somewhat replicates of their last namesake lol.
Member Since: Posts: Comments:
Quoting IKE:

Man...What a difference of 12 hours can make. Do you know what the shear and dry air is suppossed to look like in the GOM this week?
Member Since: Posts: Comments:
Diurnal minimum starting to do its job.

Member Since: Posts: Comments:
Low-level center appears to be about here:



Loop
Member Since: November 24, 2005 Posts: 635 Comments: 26681
Quoting aquak9:
petrol- yeah, east. still waking up.


Aquak, did you catch my comment about the rain dance?
Member Since: Posts: Comments:
The development chances will likely be upgraded to 50% by the 2am TWO. This means that recon should be a go for tomorrow...
Member Since: Posts: Comments:
Quoting NICycloneChaser:


That's what a storm approaching tropical depression status looks like.


Exactly.

94L still has a good amount of work to do before it becomes a TD.

Should stay 40% unless something really changes in the next 2/3 hours.
Member Since: Posts: Comments:
Member Since: Posts: Comments:
Quoting NICycloneChaser:


That's what a storm approaching tropical depression status looks like.


to me 91E looks less impressive than it did a few hours ago; center is exposed a bit too and the convection looks to be linear on the southern side
Member Since: Posts: Comments:
petrol- yeah, east. still waking up.
Member Since: Posts: Comments:

Viewing: 647 - 597

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

Local Weather

Light Rain
51 °F
Light Rain