Caribbean disturbance 94L dumping heavy rains on Jamaica

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

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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

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Surface



2500 feet

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Quoting charlottefl:
Here's my best guess looking at close up vis:

Photobucket

Too far East, I think...
By a long way.
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Member Since: July 17, 2009 Posts: 69 Comments: 25345
Quoting Grothar:


You're OK, 09. So, you've been following my coverage of this event for the past few days? I nailed it. Right to the location and timing and all. Even got it in right before Dr. Masters new post. The only thing is my arm hurts for patting myself on the back. LOL

I would do a video-blog but I don't think any of you would like my accent. I'll give you a sample and you let me know.


Don't forget to post your recipes too.

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Quoting charlottefl:
Here's my best guess looking at close up vis:

Photobucket


That would be a mid-level rotation that you are seeing on the satellite loop. The surface circulation is west of the convection.
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Cuban radar shows the rotation of the clouds.

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Quoting MississippiWx:


Not really seeing how anything could be aligned from looking at visible loops. Nonetheless, it's still a broad circulation that still needs work.


All of these maps show vorticity directly overhead the area of lowest surface pressure. That is aligned in my book.

5000 feet



10,000 feet



18,000 feet

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Here's my best guess looking at close up vis:

Photobucket
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Good afternoon......as noted by Dr. M, dry air is not as much of an issue now and 94L is starting to really moisten up in all quadrants. Still, it is amazing how "all" the big factors need to line up correctly for TD formation which is actually a rarity (especially in June). So far IMHO:

SSTs=Check
Moist Air-Almost There
Coreolis-Almost There
Anti-Cyclone = Check
Vorticity=Partialy There....Low and mid-level vorticity is there but not stacked yet in the upper levels; probably because of the bands of 40-50 knots of shear just to the north of the disurbance.

I think the missing factor is upper level stacking, but, the main difference between yesterday and today is that the anti-cyclone over the system has grown in size.....This "protection" may allow the system to finally start to blossom in the upper levels over the next 24-48 hours....Time will Tell.
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238. IKE

Quoting Grothar:


He probably saw my blog entry early this morning.
lol.

Or are you serious? You think it's going to Florida too?
Member Since: June 9, 2005 Posts: 23 Comments: 37858
237. xcool
WHXX01 KWBC 051807
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS NATIONAL HURRICANE CENTER MIAMI FL
1807 UTC SUN JUN 5 2011

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 (AL942011) 20110605 1800 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
110605 1800 110606 0600 110606 1800 110607 0600

LAT LON LAT LON LAT LON LAT LON
BAMS 16.8N 79.6W 17.2N 80.4W 17.6N 81.1W 17.7N 81.7W
BAMD 16.8N 79.6W 17.5N 80.3W 18.6N 80.7W 20.0N 80.3W
BAMM 16.8N 79.6W 17.3N 80.4W 18.0N 80.8W 18.5N 80.9W
LBAR 16.8N 79.6W 17.6N 79.9W 18.6N 79.9W 19.7N 79.0W
SHIP 25KTS 28KTS 31KTS 34KTS
DSHP 25KTS 28KTS 31KTS 34KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
110607 1800 110608 1800 110609 1800 110610 1800

LAT LON LAT LON LAT LON LAT LON
BAMS 17.7N 82.2W 17.7N 83.7W 17.8N 85.0W 18.4N 86.2W
BAMD 21.6N 79.3W 25.5N 77.5W 28.8N 78.5W 31.1N 81.0W
BAMM 19.1N 80.8W 20.3N 81.1W 22.4N 81.4W 24.4N 82.7W
LBAR 20.6N 77.6W 22.5N 73.8W 25.6N 70.1W 27.8N 65.9W
SHIP 33KTS 22KTS 0KTS 0KTS
DSHP 33KTS 22KTS 0KTS 0KTS

...INITIAL CONDITIONS...
LATCUR = 16.8N LONCUR = 79.6W DIRCUR = 310DEG SPDCUR = 4KT
LATM12 = 16.2N LONM12 = 79.1W DIRM12 = 294DEG SPDM12 = 4KT
LATM24 = 16.1N LONM24 = 78.2W
WNDCUR = 25KT RMAXWD = 175NM WNDM12 = 25KT
CENPRS = 1007MB OUTPRS = 1010MB OUTRAD = 250NM SDEPTH = M
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM
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Quoting IKE:
Joe Bastardi....tweeted this 6 hours ago....

Joe Bastardi


Tropical Disturbance
looking stronger this morning.. Should be in eastern Gulf and then
affect Florida next weekend. Keep an eye on thi
s.



He probably saw my blog entry early this morning.
Member Since: July 17, 2009 Posts: 69 Comments: 25345
Quoting NICycloneChaser:


Shear in the upper area of the GoM shouldn't be too bad, but it's path up there involves crossing the subtropical jetstream, which would likely destroy it.
When should the subtropical jet move north?
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234. xcool
AL, 94, 2011060518, , BEST, 0, 168N, 796W, 25, 1007, DB
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Quoting MiamiHurricanes09:
Yup, lmao. I'm liking the new meteorology-inclined-forecaster Grothar lol. Do you plan on making a blog?


You're OK, 09. So, you've been following my coverage of this event for the past few days? I nailed it. Right to the location and timing and all. Even got it in right before Dr. Masters new post. The only thing is my arm hurts for patting myself on the back. LOL

I would do a video-blog but I don't think any of you would like my accent. I'll give you a sample and you let me know.
Member Since: July 17, 2009 Posts: 69 Comments: 25345
Quoting KEEPEROFTHEGATE:
we could have a geirtol section the bingo section and my fav lawn bowling section all in one neat little package


lol

and sell Antique stuff on the side. Really OLD antique stuff. Nice!
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231. IKE
Joe Bastardi....tweeted this 6 hours ago....

Joe Bastardi


Tropical Disturbance
looking stronger this morning.. Should be in eastern Gulf and then
affect Florida next weekend. Keep an eye on thi
s.

Member Since: June 9, 2005 Posts: 23 Comments: 37858
Despite lack of model support, there is still a chance for 94L. We will have to see if it can make any progress today. Pressures at this buoy west of the center should be watched to see if they get below 1007mb today. The latest diurnal peak ringed in a bit lower than previous peaks.
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we could have a geirtol section the bingo section and my fav lawn bowling section all in one neat little package


lol
Member Since: July 15, 2006 Posts: 169 Comments: 53296
Quoting MiamiHurricanes09:
Anticyclone appears to be very close to vertically aligning with the circulation. The anticyclone has also strengthened...a lot.

Strengthened a lot mostly thanks to all the air that has been lifted by today's convection... good going 94l
Member Since: December 1, 2006 Posts: 2 Comments: 3619
Quoting nrtiwlnvragn:


From the early morning Marine Weather Discussion

Excerpt:

A LOW AMPLITUDE TROPICAL WAVE HAS JUST ENTERED THE FAR SE
CARIBBEAN SEA FROM 8N62W TO 16N61W MOVING W NEAR 10 KT. THE WAVE
IS NOT EXPECTED TO PROGRESS TO FAR TO THE W BEFORE IT BECOMES
RECONFIGURED INTO AN E TO W TROUGH OVER NORTHERN SECTION OF THE
EASTERN CARIBBEAN SEA TONIGHT THROUGH THE EARLY PART OF THE
UPCOMING WEEK. THE TROUGH THEN LIFTS NWD INTO THE FAR SE PORTION
OF THE SW N ATLC ZONE WED AND THU


However, I don't see this feature shown on the current or forecast surface maps.

Thanks, Appreciate that.
I am confused by it as well.
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Quoting kmanislander:


The circulation is pretty much aligned all the way from the surface to 500 mbs if you look at the maps. There is a spin slightly off to the ENE of the main circulation but it is not really interfering with the system apparently and may just be a temporary gyre within the overall circulation itself.


Not really seeing how anything could be aligned from looking at visible loops. Nonetheless, it's still a broad circulation that still needs work.
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Quoting MiamiHurricanes09:
Yup, lmao. I'm liking the new meteorology-inclined-forecaster Grothar lol. Do you plan on making a blog?
he should if he likes tell me what he wants and i will design the code
Member Since: July 15, 2006 Posts: 169 Comments: 53296
Quoting pottery:

On that map you posted...
what happened to the T-Wave that was approaching 94L ???
It's not shown....


From the early morning Marine Weather Discussion

Excerpt:

A LOW AMPLITUDE TROPICAL WAVE HAS JUST ENTERED THE FAR SE
CARIBBEAN SEA FROM 8N62W TO 16N61W MOVING W NEAR 10 KT. THE WAVE
IS NOT EXPECTED TO PROGRESS TO FAR TO THE W BEFORE IT BECOMES
RECONFIGURED INTO AN E TO W TROUGH OVER NORTHERN SECTION OF THE
EASTERN CARIBBEAN SEA TONIGHT THROUGH THE EARLY PART OF THE
UPCOMING WEEK. THE TROUGH THEN LIFTS NWD INTO THE FAR SE PORTION
OF THE SW N ATLC ZONE WED AND THU


However, I don't see this feature shown on the current or forecast surface maps.
Member Since: September 23, 2005 Posts: 14 Comments: 10875
220. IKE

Quoting tennisgirl08:


We need a rainmaker, that is for sure!!! However, will the subtropical jetstream kill the system before reaching the northern gulf states?? just wondering. i am in alabama
Not according to the latest CMC bomber....


Member Since: June 9, 2005 Posts: 23 Comments: 37858
Quoting NICycloneChaser:
Judging by an upload to youtube 6 minutes ago, I suspect we should see a certain user by the name of 'Levi32' anytime now...


+1 lol
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Is there a reason for you all not answering my question??
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Quoting Grothar:


Hey, 09, you got nailed and I missed it? I wish someone would have called me.

Yup, lmao. I'm liking the new meteorology-inclined-forecaster Grothar lol. Do you plan on making a blog?
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Good morning all.

Blog update:

Tropical Tidbit for Sunday, June 5th, with Video
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Quoting MississippiWx:
The circulation is still too broad on visible. The spin in the middle of the convection is mid level and it looks like the surface rotation is south of the Western tip of Jamaica. It still has a long ways to go, but it is starting to take baby steps towards being classified.


The circulation is pretty much aligned all the way from the surface to 500 mbs if you look at the maps. There is a spin slightly off to the ENE of the main circulation but it is not really interfering with the system apparently and may just be a temporary gyre within the overall circulation itself.
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Quoting IKE:
More models trending into the GOM.

Rainmaker anyone?


We need a rainmaker, that is for sure!!! However, will the subtropical jetstream kill the system before reaching the northern gulf states?? just wondering. i am in alabama
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Judging by an upload to youtube 6 minutes ago, I suspect we should see a certain user by the name of 'Levi32' anytime now...
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Quoting HurricaneSwirl:
Does anyone know where I can find the NHC-supported TVCN model forecasts?


It is shown on the plots from SFWMD
Member Since: September 23, 2005 Posts: 14 Comments: 10875
Quoting MiamiHurricanes09:
12z ECMWF kills it when it enters the Gulf of Mexico. The strongest the system got was 1006mb in 24 hours.


Hey, 09, you got nailed and I missed it? I wish someone would have called me.

Member Since: July 17, 2009 Posts: 69 Comments: 25345
Quoting nrtiwlnvragn:
TAFB 72 hour surface forecast.... not much movement.



but nearly on top of me
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Quoting nrtiwlnvragn:
TAFB 72 hour surface forecast.... not much movement.



On that map you posted...
what happened to the T-Wave that was approaching 94L ???
It's not shown....
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203. IKE
NOGAPS run....into the GOM..... https://www.fnmoc.navy.mil/wxmap_cgi/index.html
Member Since: June 9, 2005 Posts: 23 Comments: 37858
Anticyclone appears to be very close to vertically aligning with the circulation. The anticyclone has also strengthened...a lot.

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Quoting tennisgirl08:
If it holds its own by tomorrow, i think we will have a TD designated when HH fly in. What is the wind shear like in the GOMEX over the next 3-5 days??


Shear in the upper area of the GoM shouldn't be too bad, but it's path up there involves crossing the subtropical jetstream, which would likely destroy it.
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Does anyone know where I can find the NHC-supported TVCN model forecasts?
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Quoting VAbeachhurricanes:


not a chance


nope you are wrong anything has a chance even 94L now give it some time and it will explode I think
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The circulation is still too broad on visible. The spin in the middle of the convection is mid level and it looks like the surface rotation is south of the Western tip of Jamaica. It still has a long ways to go, but it is starting to take baby steps towards being classified.
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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.