Lesser Antilles Disturbance 97L Still Disorganized

By: Dr. Jeff Masters , 2:34 PM GMT on September 03, 2013

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A tropical wave over the Lesser Antilles Islands (Invest 97L) is moving west-northwest at 10 mph, and is bringing sporadic heavy rain showers to the islands. Top sustained winds observed in the islands as of 10 am AST Tuesday were mostly below 15 mph. Heavy thunderstorm activity has been low since Monday, and is spread out, as seen on satellite loops. The thunderstorms are poorly organized, and there is no sign of a well-organized surface circulation. Martinique radar shows little evidence of rotation to the echoes, and no low-level spiral bands forming. Upper level winds are favorable for development, with wind shear a low 5 - 10 knots, and an upper-level anticyclone overhead. An area of dry air from the Saharan Air Layer (SAL) surrounds 97L and is interfering with development, though the the 12Z Tuesday balloon sounding from Guadeloupe near the center of 97L showed moist air through the entire depth of the atmosphere.


Figure 1. Latest satellite image of Invest 97L.

Forecast for 97L
Wind shear is expected to be low through Friday, and ocean temperatures will be warm, 29°C. The disturbance has not been able to generate enough thunderstorms to moisten the surrounding atmosphere much, and dry air may continue to slow down development over the next few days. The models take 97L to the west-northwest, bringing it near or over Puerto Rico or Hispaniola on Wednesday night. A track over the high mountains of Hispaniola would disrupt the circulation of 97L, forcing the storm to regroup on Thursday over the Southeast Bahamas and Turks and Caicos Islands. The best chance for development of 97L would appear to be on Friday, after the storm has finished its encounter with Hispaniola. This morning's 00Z run of the experimental GFDL ensemble--which produces 10 simulations with slightly varying initial conditions to create a plume of potential storm tracks--foresees that once 97L organizes into a tropical depression, it might take only two days for it to intensify into a hurricane to the north of Hispaniola. The wave will bring heavy rain showers to the Lesser Antilles islands on Tuesday and Wednesday, and this activity will likely spread to Puerto Rico, the Virgin Islands, the Dominican Republic, and Haiti on Wednesday and Thursday. These rains will be capable of causing life-threatening flash flooding and mudslides in mountainous regions of Puerto Rico and Hispaniola. Of our three reliable models for predicting genesis, the UKMET, GFS, and European models, only the UKMET model develops the disturbance, predicting it will become a tropical depression over the Central Bahamas on Saturday. There will be a strong trough of low pressure along the U.S. East Coast this weekend, which will be capable of turning 97L to the north before the storm can hit the U.S. In their 8 am EDT Tuesday Tropical Weather Outlook, NHC left the 5-day odds of formation of 97L at 50%, and 2-day odds at 20%. The Hurricane Hunters are on call to investigate 97L Wednesday afternoon. The flight scheduled for today will likely be cancelled. The Hurricane and Severe Storm Sentinel Mission, a 5-year field project utilizing two remotely crewed Global Hawk aircraft to overfly tropical storms and hurricanes, will have one of their aircraft investigate 97L today, and again on Wednesday. You can follow the progress of the aircraft using NASA's live-plane tracker map (Global Hawk AV6 is tail number NASA872, and Global Hawk AV1 is tail number NASA871.)

98L off the coast of Africa and a Yucatan Peninsula tropical wave
A tropical wave that emerged from the coast of Africa on Monday (Invest 98L) is expected to track northwest over the Cape Verde Islands. This course will take 98L into a region of ocean where historically, very few tropical cyclones have made the long journey across the Atlantic to affect North America. In their 8 am EDT Tuesday Tropical Weather Outlook, NHC put the 5-day odds of development at 20%.

A tropical wave over Mexico's Yucatan Peninsula has a respectable area of heavy thunderstorms associated with it that is bringing heavy rains. This activity will push over the extreme Southern Gulf of Mexico's Bay of Campeche on Wednesday. The wave will have two days over water to develop before moving ashore on the Mexican coast between Veracruz and Tampico on Friday. In their 8 am EDT Tuesday Tropical Weather Outlook, NHC put the 5-day odds of development at 30%, and 2-day odds at 20%.

Jeff Masters

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WOAH..

216 Hours
Member Since: August 19, 2006 Posts: 13 Comments: 15738
Note the storms marching south with the front, to stall along the coast and wash out next couple of days.

Then the GOM is open to Missouri via the River.



Member Since: July 3, 2005 Posts: 426 Comments: 128865
.
Member Since: May 30, 2013 Posts: 0 Comments: 566
Quoting 502. RascalNag:


You're right it has vanished - underneath convection, that is. It's definitely there. 14.6N, 63.4W seems a good place to put it.

Yes but maybe it would get a little tug NE due to the increased convection as its just trying to line up with the convection but should continue W bound shortly
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9 hrs ago, Microwave Look, will compare to todays evening pass,if we get one.

IR/WV/Microwave RGB (IR [R], WV [G], MI89 [B])


Member Since: July 3, 2005 Posts: 426 Comments: 128865
Hurricane free August disappoints commodities bulls




that just breaks my heart that it didn't cost me an arm and a leg to gas my car because a hurricane shut down production...
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Interesting mlc near Cancun. Hmmm
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Quoting 507. HurricaneHunterJoe:


I still " feel your pain" CaribBoy


I'm good don't worry :)
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NCEP Caribbean Desk just updated their discussion. Here is the section on the projected rain for PR and Hispanola with the full link below. Big time flooding on the horizon for those folks:

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
221 PM EDT TUE SEP 03 2013

TROPICAL WAVE ALONG 56W AND THE ONE ALONG 62W ARE TO GRADUALLY PHASE AS THE LATTER MIGRATES ACROSS THE EASTERN CARIBBEAN. NHC IS MONITORING THIS AREA FOR POSSIBILITY OF TROPICAL CYCLONE FORMATION. AS THE WAVE PROPAGATES ACROSS THE EASTERN CARIBBEAN IT IS TO THEN SUSTAIN A MOIST SOUTHEASTERLY FLOW...WITH DEEP MOISTURE TO POOL ACROSS PUERTO RICO-VIRGIN/LEEWARD ISLES TO HISPANIOLA.
EARLY IN THE CYCLE MOST ACTIVE CONVECTION IS EXPECTED ACROSS THE FRENCH-LEEWARD TO VIRGIN ISLES WHERE IT IS TO SUSTAIN RAINFALL AMOUNTS OF 15-30MM/DAY AND MAXIMA OF 40-80MM. AS IT ENTERS PUERTO RICO-EASTERN HISPANIOLA THIS WILL INCREASE TO 25-50MM/DAY AND MAXIMA OF 75-125MM. STRONG TOPOGRAPHICAL FORCING COULD LEAD TO LOCALIZED HEAVY RAINFALL AMOUNTS OF 150-200MM. ACROSS HAITI IT IS TO THEN SUSTAIN RAINFALL AMOUNTS OF 05-10MM/DAY AND MAXIMA OF 15-20MM BY 72-84 HRS. THROUGH 96 HRS MAXIMA IS TO INCREASE TO 30-60MM.


Link
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Moved it

AL, 97, 2013090318, , BEST, 0, 150N, 630W, 30, 1007, LO
Member Since: September 23, 2005 Posts: 14 Comments: 11221
Quoting 481. CaribBoy:
Looking South


Looking North



I still " feel your pain" CaribBoy
Member Since: September 18, 2010 Posts: 0 Comments: 5234
Quoting 502. RascalNag:


You're right it has vanished - underneath convection, that is. It's definitely there. 14.6N, 63.4W seems a good place to put it.


Debating on stupidities is a waste of time XD
Member Since: October 6, 2007 Posts: 0 Comments: 6254
One thing fer sure, no model's no'r Bloggers called for 97L to go into Neutral for 48 hours..


HArumphhh'
Member Since: July 3, 2005 Posts: 426 Comments: 128865
its looking like lots of storms going out to sea this year the east coast will be safe this year.
Member Since: March 12, 2013 Posts: 29 Comments: 57136
Hurricane-free August disappoints commodities bulls
Financial Times, September 3, 2013 6:34 pm
By Emiko Terazono in London

Lol, WU-bloggers aren't the only ones with some frustration.

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Quoting 497. CaribBoy:


Seriously Wunderkidcayman, 15N 62W seems the right location. Earlier though, the southern center looked quite nice, but now it looks like it has just vanished.


You're right it has vanished - underneath convection, that is. It's definitely there. 14.6N, 63.4W seems a good place to put it.

Edit: MAybe more at 62.9W. Seems to have jumped under the convection to its East. Still, it's alive and well.
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501. Kyon5
Moving WNW-NW if one looks at this radar: Link


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Quoting 462. Patrap:
If 97L can convert all that girth into a Caribbean Hurricane downstream..








It could have some oooommmmpppphhhhhhhh to it.......lets wait and see.......it looks to be organizing at a nice pace........longevity is the key .....just has not happened this year.
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Member Since: July 3, 2005 Posts: 426 Comments: 128865
lots of dry air where normally not this time of year



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Quoting 485. wunderkidcayman:

At that location is nothing no indication of the COC but it show the NE side of it


Seriously Wunderkidcayman, 15N 62W seems the right location. Earlier though, the southern center looked quite nice, but now it looks like it has just vanished.
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Quoting 487. ricderr:
...always been a fan of 0 %

With that kind of math... one should deduce that we have a 50% Chance of having a tropical disturbance in the next 48 hours....

LOL
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12z UKMET last frame

Member Since: August 19, 2006 Posts: 13 Comments: 15738
Hmmm, the Haus is betting on N by NW then Woosh'


BAM shallow is the outlier....

Hmm, I wunder...?

Dooodle Looo,

wah, wah, wahhhhhhhhh





Member Since: July 3, 2005 Posts: 426 Comments: 128865
Quoting 480. wunderkidcayman:

This makes sense



Yep....Looking at it on vis sat....was thinking 14.5N and 63.0W
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Quoting 425. Drakoen:


If the answer to this is no do I still need to respond lol?


lol no. i just thought your handle was familiar.
Member Since: April 24, 2011 Posts: 1 Comments: 601
A lot left to be desired.

Member Since: October 28, 2006 Posts: 57 Comments: 30575
12z

Member Since: August 19, 2006 Posts: 13 Comments: 15738
Quoting 483. ricderr:

Not surprised at all I'm taking this straight to the trash
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Member Since: August 19, 2006 Posts: 13 Comments: 15738
...always been a fan of 0 %
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Model runs and long-term development aside for the moment, this "wave" is going to bring some heavy rains, and threatening flooding and mudslides, to our friends in USVI and Puerto Rico.

They will need to take the appropriate precautions regardless of development; time to start thinking about sandbags if your property is prone to flooding in these areas from copious tropical rain makers.

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Quoting 469. CaribBoy:


Probably WNW 290°

At that location is nothing no indication of the COC but it show the NE side of it
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Quoting 471. air360:
Could someone please explain to me how to read these:

AL, 97, 2013090318, , BEST, 0, 150N, 621W, 30, 1007, LO

Sorry, still learning :)



Link
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is this the dead zone? nothings working right this year

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Looking South


Looking North

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Quoting 457. nrtiwlnvragn:
TXNT28 KNES 031804
TCSNTL

A. TROPICAL DISTURBANCE (97L)

B. 03/1745Z

C. 14.4N

D. 63.2W

E. FIVE/GOES-E

F. T1.0/1.0/D1.0/24HRS

G. IR/EIR/VIS

H. REMARKS...LOW LEVEL CIRCULATION IS BECOMING BETTER DEFINED ACCORDING
TO ANIMATED VISIBLE IMAGERY. IN ADDITION CONVECTION HAS INCREASED NEAR
THE CENTER OF CIRCULATION OVER THE LAST 6 HOURS...MEASURING SLIGHTLY MORE
THAN 2/10 FOR A DT OF 1.0. MET AND PT ARE ALSO 1.0. FT IS BASED ON DT.

I. ADDL POSITIONS

NIL


...TURK


Link

This makes sense

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Quoting 471. air360:
Could someone please explain to me how to read these:

AL, 97, 2013090318, , BEST, 0, 150N, 621W, 30, 1007, LO

Sorry, still learning :)

date and time. 18z being 2pm est.

best guess location is 15.0N and 62.1W. 1007mb low.
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Quoting 475. RGVtropicalWx13:

Old update that says 12z..were at 18z now


Post already corrected - C&P mistake.
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144 hours
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Quoting 468. DavidHOUTX:


uhhh


LOL - yeah, I caught that too. A little cut&paste error.

:D
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Quoting 463. daddyjames:
AL, 97, 2013090312, , BEST, 0, 148N, 617W, 25, 1009, LO, 34, NEQ,

A little east of where most of us have been focusing.

Old update that says 12z..were at 18z now
Member Since: May 30, 2013 Posts: 0 Comments: 566
Wow BEST track got it wrong again meaning model runs for 18Z no good

Right now I'm seeing two thing that might be going on #1 the COC is still near 14.2N 63.3W and the the east side has gotten elongated so instead of a circular flow W, SW, S, NE, E you got W on S side SW on SE side WSW on E side and on the NE side you have WSW sharply turning E toward the COC #1 we now got two COC spinning around a central COC near 14.3N 62.0W
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850mb Vort looks better. 97L still looks to be separating itself further from the area of disturbed weather to the east.

Member Since: July 15, 2006 Posts: 17 Comments: 10284
.
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Could someone please explain to me how to read these:

AL, 97, 2013090318, , BEST, 0, 150N, 621W, 30, 1007, LO

Sorry, still learning :)
Member Since: Posts: Comments:


Wxrisk.com
HUGE OUTBREAK OF AFRICAN DUST IN TROPICAL ATLANTIC
Yesterday at 12:59pm ·
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Quoting 463. daddyjames:
AL, 97, 2013090312, , BEST, 0, 148N, 617W, 25, 1009, LO, 34, NEQ,


Probably WNW 290°
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Quoting 463. daddyjames:
AL, 97, 2013090312, , BEST, 0, 148N, 617W, 25, 1009, LO, 34, NEQ,


uhhh
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12z HWRF got a thing for Bermuda?

Member Since: August 19, 2006 Posts: 13 Comments: 15738

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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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