Tropical depression likely by Tuesday in Western Caribbean

By: Dr. Jeff Masters , 8:45 PM GMT on October 08, 2007

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A vigorous surface circulation has developed in association with a broad area of low pressure over the Western Caribbean (94L). A pass from the European ASCAT satellite at 11:02 am EDT showed that the surface circulation had gotten much less elongated, compared to this morning's QuikSCAT pass. Top winds were only about 10 mph in the 11 am ASCAT pass, but have no doubt increased since then. Satellite loops show a very large surface circulation covering the entire Western Caribbean, with a concentrated area of thunderstorms forming near the center of circulation. Surface pressures remain very low over the entire Western Caribbean. Wind shear is less than 10 knots, and is expected to remain less than 10 knots through Thursday. It is likely that this system will form into a tropical depression on Tuesday, despite the very large amount of atmosphere it is trying to spin up.

Steering currents are weak in the Western Caribbean, but most of the models show a slow motion to the west or northwest that will take 94L over Belize or Mexico's Yucatan Peninsula by Thursday. It is unlikely 94L will have time to become a hurricane before it moves over the Yucatan, and the main threat from the system will be heavy rain. These rains may cause significant flooding problems in Belize and Mexico's Yucatan. Heavy rains may also affect northeast Guatemala, but should not cause significant flooding.

There is a strong trough of low pressure forecast to swing across the U.S. this week, which could turn 94L northwards into Western Cuba, the Florida Keys, or Southwest Florida. However, this is unlikely, since none of the reliable computer models are forecasting such a turn.

It is likely that 94L will eventually emerge into the Gulf of Mexico or Western Caribbean after spending a few days over the Yucatan. When it does so, it will probably be intact enough to re-strengthen, since it is such a large system. Its long-term fate it highly uncertain, as the steering currents are weak and the storm's intensity will be controlled by interaction with land.

Elsewhere in the tropics
A nearly stationary tropical disturbance a few hundred miles north of Puerto Rico is generating a large area of thunderstorms. The region is under 15-20 knots of wind shear, due to strong upper level winds from the west. These winds are blowing the heavy thunderstorm activity downwind, to the east of the elongated surface circulation apparent on visible satellite imagery. Wind shear is expected to remain 15-30 knots over the region over the next three days. The high shear should discourage any significant development.

I'll have an update in the morning.

Jeff Masters

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530. icmoore
1:32 PM GMT on October 09, 2007
Taz, isn't "Thanks" as worthless as "Good Morning"?
Member Since: July 18, 2005 Posts: 9 Comments: 4146
529. IKE
1:29 PM GMT on October 09, 2007
NEW BLOG!
Member Since: June 9, 2005 Posts: 23 Comments: 37858
528. Bonedog
1:28 PM GMT on October 09, 2007
thats why i said for some reason. I mean it has it going warm core NORTH of Labrador. Unless some wierd act of God has happened the waters up there are only 14 to 17C I dont even think and extratropical system could pull a warm core with those temps.

Just saying what the models showed. But will be a system to watch nontheless even if it stays extratropical. Any 967mb storm should be awsome to see
Member Since: July 14, 2005 Posts: 14 Comments: 7418
525. nrtiwlnvragn
1:22 PM GMT on October 09, 2007
Tazmanian

Last night you were looking for models of the pacific off the west coast.

NOGAPS

GFS
Member Since: September 23, 2005 Posts: 14 Comments: 11262
524. surfmom
1:22 PM GMT on October 09, 2007
Thanks Leftovers --I know the "be careful what I wish for lesson". Dean was great (but I felt guilty for the Mexicans) 90L was very sweet, beautiful glassy southie wavemaker and it di not cause anyone any trouble --that is the kind I like.
Member Since: July 18, 2007 Posts: 30 Comments: 26536
523. NEwxguy
1:21 PM GMT on October 09, 2007
bonedog,I've never seen a system go warm core in the north atlantic,I would assume that is extremely rare
Member Since: September 6, 2007 Posts: 886 Comments: 15947
522. weatherboyfsu
1:19 PM GMT on October 09, 2007
Good morning,

Doesnt look like anythings going to come of 94L anytime soon. Boy, the models sure are on a role in their predictions......
Member Since: July 17, 2005 Posts: 0 Comments: 1025
520. leftovers
1:19 PM GMT on October 09, 2007
Second that number 1 fan. This system might be down there for a while. Dr Grey said at the beginning of the month there would be one more major. Well?
518. nrtiwlnvragn
1:17 PM GMT on October 09, 2007
BROAD LOW IS EXPECTED TO MOVE INLAND OVER YUCATAN OR BELIZE IN 24-36 HOURS OR SO AND THE MORE RELIABLE HURCN TRACK MODELS KEEP THE AREA OF LOW PRESS OVER THE YUCATAN OVER THE NEXT 3 DAYS THEREBY LESSENING THE CHANCES FOR TROPICAL CYCLONE DEVELOPMENT.

Marine Weather Discussion
Member Since: September 23, 2005 Posts: 14 Comments: 11262
517. cantoriesnumber1fan
1:16 PM GMT on October 09, 2007
508. Tazmanian 1:08 PM GMT on October 09, 2007 Hide this comment.
7.Do not "1st!", "1st post!", or any of the numerical/linguistic derivatives. This is a worthless use of blog space.



6.No comments that contain only personal notes such as, "Good Morning!", or "You've got mail, X".

Way too much time on your hands dude.
516. Bonedog
1:16 PM GMT on October 09, 2007
NEwxguy I have been watching the North Atlantic Low all morning. Wait till later today7 when a new Low currently off the Mass coast spins up. OPC calling for Hurricane force and all the models for some reason are showing it going warm core and bombing to 967mbs
Member Since: July 14, 2005 Posts: 14 Comments: 7418
514. thelmores
1:13 PM GMT on October 09, 2007
If 94L does loop around and re-emerge, it could still be a player......
Member Since: September 8, 2005 Posts: 0 Comments: 3805
513. leftovers
1:13 PM GMT on October 09, 2007
Dont hope too much surf mom might get more swell that we can handle. Noone knows for sure what 94 will end up doing.
512. 21N71W
1:12 PM GMT on October 09, 2007
Taz relax! was just trying to see if my photo was up!!!!
Member Since: August 1, 2006 Posts: 0 Comments: 180
511. NEwxguy
1:12 PM GMT on October 09, 2007
good morning all, I see 94l still trying to get his act together,and anybody see that low in the north atlantic wrapping up
Member Since: September 6, 2007 Posts: 886 Comments: 15947
507. 21N71W
1:05 PM GMT on October 09, 2007
morning
Member Since: August 1, 2006 Posts: 0 Comments: 180
505. thelmores
12:59 PM GMT on October 09, 2007
nash, this is a couple runs in a row the GFDL has shown that.... the 00z CMC shows about the same.....
Member Since: September 8, 2005 Posts: 0 Comments: 3805
504. nrtiwlnvragn
12:59 PM GMT on October 09, 2007
94L Quikscat
Member Since: September 23, 2005 Posts: 14 Comments: 11262
503. nash28
12:57 PM GMT on October 09, 2007
The 00z GFDL has 94L making a tight loop and ending up right back where it started.
Member Since: July 11, 2005 Posts: 190 Comments: 16972
502. icmoore
12:55 PM GMT on October 09, 2007
Good morning everyone, when looking at the water vapor loop I noticed all the dry air pushhing into the GOM. Dumb question, is that from the trough that Stormw and all were talking about yesterday?
Member Since: July 18, 2005 Posts: 9 Comments: 4146
501. surfmom
12:54 PM GMT on October 09, 2007
Morning! Nice pictures of Wilma' Surge. Dean inded did was not the wavemaker Wilma was. Keeping an eye on 94L, I don't want any trouble from this one, but it would be nice to get at least one more swell maker for the Gomex. Presently, I am not too hopeful
Member Since: July 18, 2007 Posts: 30 Comments: 26536
500. aspectre
12:43 PM GMT on October 09, 2007
06 GMT 10/9/07 18.1N _86.6W
94L was about 78miles/125kilometres offshore from Belize's NorthEastern border with Mexico.
Member Since: August 21, 2007 Posts: 0 Comments: 4860
499. aspectre
12:38 PM GMT on October 09, 2007
06 GMT 10/9/07 1 8.1N _86.6W
94L was about 78miles/125kilometres offshore from Belize's NorthEastern border with Mexico.
Member Since: August 21, 2007 Posts: 0 Comments: 4860
498. guygee
12:36 PM GMT on October 09, 2007
With the deep tropical moisture bottled up in the Caribean by upper-level winds, and deep-layer dry air entrenched from east of the Bahamas to the E GOM, it looks like the autumnal front poised to drop down over the central FL peninsula in a couple of days will make a fairly dry passage, with perhaps only a brief passing shower or T-shower at most if the timing is favored by the overland dmax. This morning's MLB NWS AFD supports this forecast:

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
335 AM EDT TUE OCT 9 2007
[...]
THU...SHORTWAVE TROUGH DIGGING TO THE MID ATLANTIC COAST WILL DRIVE A FRONTAL BOUNDARY INTO THE STATE. THE GFS IS MOST AGGRESSIVE NOW...WHICH IS A REVERSAL FROM PREVIOUS DAYS WHERE THE ECMWF SHOWED THE TROUGH DIGGING THE FURTHEST SOUTH.

IN ANY EVENT...IT LOOKS LIKE THIS WILL BE A DRY FRONTAL PASSAGE AS DEEP MOISTURE IS WELL TO THE SOUTH. THE GFS SHOWS A LITTLE MOISTURE CONVERGENCE ACROSS THE SOUTH HALF IN THE AFTERNOON...BUT MOS POPS ARE TOO LOW TO INTRODUCE ANY RAIN CHANCES. IT LOOKS LIKE A WARM DAY WITH LIGHT WEST/NORTHWEST FLOW AHEAD OF THE FRONT.
[...]

Executive Summary: 94L will not be riding up ahead of the trough as a Wilma-like CAT 5 to destroy Tampa :~)
Member Since: September 16, 2005 Posts: 0 Comments: 3174
497. Bonedog
12:24 PM GMT on October 09, 2007
I dont like to get into the rukus but the person who posted wilma had 15nm winds must have used a very late advisory.

here is advisory 35a
HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 85 MILES FROM THE
CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP
TO 230 MILES. A WIND GUST TO 53 MPH WAS REPORTED AT HAVANA CUBA AND
A WIND GUST TO 49 MPH WAS REPORTED AT KEY WEST.

here is advisory 36a which was at landfall
HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 90 MILES FROM THE
CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 230MILES. A WIND GUST TO 95 MPH WAS REPORTED AT EVERGLADES CITY AND A
GUST TO 75 MPH WAS REPORTED AT NAPLES FLORIDA.

please if your going to post information please try to post accurate historical information.
Member Since: July 14, 2005 Posts: 14 Comments: 7418
496. islagal
12:17 PM GMT on October 09, 2007
Hola. So it looks as if the Cancun area is out of danger for 94L...correct?
Member Since: September 3, 2007 Posts: 0 Comments: 37
495. SamTeam
12:11 PM GMT on October 09, 2007
489. Bonedog 6:52 AM CDT on October 09, 2007

slow morning LOL.


That would be an understatement...where is everyone? :)
Member Since: September 22, 2007 Posts: 0 Comments: 213
494. PensacolaDoug
12:06 PM GMT on October 09, 2007
94L still not much of a threat?
Member Since: July 25, 2006 Posts: 0 Comments: 591
493. SamTeam
12:05 PM GMT on October 09, 2007
Mornin' Y'all! How goes it with the 94 watch?
Member Since: September 22, 2007 Posts: 0 Comments: 213
492. jtn
12:03 PM GMT on October 09, 2007
lightningcharmer I don't know where you found your information but I was in Wilma, and that's not what I experienced.
Here is an image of windfield from NOAA.



His info is correct, wilma had a "very small" wind field at max intensity in the carib like many very intense hur do.
491. Nashda
11:58 AM GMT on October 09, 2007
Good Morning WUbloggers!!!!!!!
490. Bonedog
11:57 AM GMT on October 09, 2007
wonder if Doc will talk about the system thats spinning up in the north atlantic. all the models I looked at show it going warm core and hitting upper 900mbs and the OPC shows it as hurricane force and 967mbs. Extratropical system going tropical?

Link
Member Since: July 14, 2005 Posts: 14 Comments: 7418
489. Bonedog
11:52 AM GMT on October 09, 2007
slow morning LOL.

94L looks to be close to land am I correct? I think Doc is right, just a rain maker. What happens after it crosses or reemerges is going to be the thing to watch. Right now its a rain event more then anything else.

Prayers to those in the path of this system.
Member Since: July 14, 2005 Posts: 14 Comments: 7418
488. leftovers
11:48 AM GMT on October 09, 2007
Hows it? Thundra what part of the world do you live?
487. Patrap
11:40 AM GMT on October 09, 2007

GOES-12 Channel 3 (WV) GOM Still

Click to ENlarge

Link
Member Since: July 3, 2005 Posts: 426 Comments: 129089
486. Patrap
11:38 AM GMT on October 09, 2007
GOM IR Loop


Link
Member Since: July 3, 2005 Posts: 426 Comments: 129089
485. Bonedog
11:37 AM GMT on October 09, 2007
dont think it will get that cold. Upper 30s maybe.
Member Since: July 14, 2005 Posts: 14 Comments: 7418
484. TampaSpin
11:33 AM GMT on October 09, 2007
94l just needs to be watched.
Member Since: September 2, 2007 Posts: 179 Comments: 20448
483. Thundercloud01221991
11:13 AM GMT on October 09, 2007
yea if those nor' easters can pull in enough cold air we may have snow over W NY
Member Since: August 1, 2006 Posts: 28 Comments: 3716
482. Bonedog
11:04 AM GMT on October 09, 2007
I hear ya Thunder. Going from record highs in the upper 80s to 90 in NJ yesterday down into the 60s later this week. Going to be a wild weather ide for sure. Plus the possiblity of two Nor'Easters this week up here.

Then looking at the tropics looks like we will have a system Today and deal with it all week.

So much for the lull we were all in.
Member Since: July 14, 2005 Posts: 14 Comments: 7418
481. Thundercloud01221991
11:00 AM GMT on October 09, 2007
here in W NY we are beginning our free fall in temps
Member Since: August 1, 2006 Posts: 28 Comments: 3716
480. underthunder
10:56 AM GMT on October 09, 2007
the high here today is to reach 91 degrees....please lord...some rain and cooler weather would be nice...
Member Since: August 9, 2006 Posts: 0 Comments: 96

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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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