Lesser Antilles Disturbance 97L a Threat to Develop

By: Dr. Jeff Masters , 2:46 PM GMT on September 01, 2013

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A tropical wave over the Lesser Antilles Islands (Invest 97L) is moving westward at 15 mph, and is bringing heavy rains and gusty winds to the islands. Top sustained winds in the islands as of 10 am AST Sunday were 26 mph at Monserrat. Heavy thunderstorm activity has sharply increased since Saturday, as seen on satellite loops. A large circulation is evident, with some westerly winds blowing to the south of the disturbance. However, the thunderstorms are poorly organized, and there is no sign of a well-organized surface circulation. Martinique radar shows some rotation to the echoes, though well-organized spiral bands are not evident, and do not appear to be forming. Wind shear has dropped to a moderate 10 - 20 knots over the system. An area of dry air from the Saharan Air Layer (SAL) surrounds 97L and is interfering with development.


Figure 1. Latest satellite image of Invest 97L.

Forecast for 97L
Wind shear is expected to be in the low to moderate range for the next five days, and ocean temperatures will be warm, 28 - 29°C. The disturbance is steadily moistening the atmosphere and is moving into a moister environment, so dry air will be less of an impediment to development as the week progresses. The main factor keeping the disturbance from developing over the next two days would appear to be the fact that 97L is quite large, and is stretched out from east to west over a wide expanse. Large, elongated systems like 97L usually take several days to consolidate and spin up. Another factor that will likely retard development is the presence of strong surface trade winds over the Eastern Caribbean ahead of 97L, south of the Dominican Republic. These strong trade winds are a common feature of the Eastern Caribbean, and make the region something of a hurricane graveyard. As the surface wind flow to the west of 97L accelerates into this wind max, air will be sucked from aloft downward towards the surface, creating sinking air, interfering with the formation of thunderstorm updrafts. The best chance for development of 97L would appear to be on Wednesday or Thursday, when the disturbance reaches the Central Caribbean. The wave will likely spread heavy rains to Puerto Rico, the Virgin Islands, and the Dominican Republic by Tuesday, and to Haiti by Wednesday. These rains will be capable of causing life-threatening flash flooding and mudslides in mountainous regions in 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 south of Haiti on Wednesday, and near Jamaica on Thursday. In their 8 am EDT Sunday Tropical Weather Outlook, NHC boosted the 5-day odds of formation of 97L to 30%, and the 2-day odds to 20%.


Video 1. You can see why landslides triggered by heavy rains from a tropical cyclone are among the most dangerous hazards of these storms, thanks to a dashboard cam that caught this extraordinary rock slide in Northeast Taiwan on August 31, 2013, after heavy rains from a cold front drenched the island with up to 200 mm (7.87") of rain in 24 hours. The rains fell upon soils already saturated by Thursday's torrential rains from Tropical Storm Kong-Rey, which dumped up to 482 mm (19") of rain on Taiwan, killing three people. The driver of the car caught in the rock slide survived with minor injuries. Thanks go to wunderground member Robert Speta for bringing this video to my attention. A separate video showing the damage to the car and the course of the rock slide is here.

Jeff Masters

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18z HWRF.

Member Since: Posts: Comments:
1504. Kumo
Quoting 1451. stormpetrol:
Anyone knows what sauce is best with crow? I need some! :))


This might provide you with some useful info.

http://www.crowbusters.com/recipes.htm

Check out The
"So good you'll want to slap your mother-in-law"
Recipe
lol!
Member Since: Posts: Comments:
Quoting 1500. prcane4you:
Aqui se habla espanol.


Le falta el palito a la n

ññññññññññññ
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Quoting 1457. GTstormChaserCaleb:
Unless it strengthens like the HWRF and GFDL says it will.


I can't offer an opinion for the HWRF, but I've personally watched the GFDL go bonkers several times during cyclogenesis. It's practically an idiot model until something is actually up and churning. After then, it has a fair track record for track, but that's about it. There were some modifications a few years back that were designed to help forecast intensity, but I don't think those have worked out too well either.
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Quoting 1495. JRRP:

sera imposible


Very complicated scenario... Even for GFS...
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Quoting 1495. JRRP:

sera imposible
Aqui se habla espanol.
Member Since: Posts: Comments:
Quoting 1483. moonlightcowboy:
Latest sfc map shows the twave higher in latitude and extremely tilted sw to ne, but with the low still moving directly west from the southern end of the wave axis.



That low has been sitting there forever. The steering is very weak and 97L does not appear to be going anywhere in a hurry. Those models calling for a track over Hispaniola must have concluded that 97L will follow the weakness being created by the ULL but only time will tell. All depends if 97L and the ULL are both moving at a snails pace otherwise the ULL will retrograde and a high will build in to the N of Hispaniola and force 97L or whatever it becomes to the W.

All guess work for now.




Member Since: August 19, 2006 Posts: 0 Comments: 15948
97L will merge with Wave SE of it,.... ULL in the N will help in the process....

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Quoting 1460. FunnelVortex:


Scott is not a troll.
Read my lips.......TRACKER.
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Quoting 1489. 19N81W:
as suspected doesn't look very impressive tonight
WE HAD A few tropical storms die out around here in the last few years. maybe this invest will die out to..u never know
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1495. JRRP
Quoting sunlinepr:
Hey, where are you going? Jump over...
No se atreve a brincar las Antillas....


sera imposible
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Quoting 1415. prcane4you:
Where..................................is the LLC...........................................,I'm tired to ask the same question.


According to the folks at the NHC
TROPICAL WAVE APPROACHING THE LESSER ANTILLES EXTENDS FROM
21N56W THROUGH A 1009 MB LOW NEAR 15N60W TO 13N60W
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Stormpetrol- I like the GRACE Jamaican Rum BBQ sauce,but dont go marinating any birds just yet
SP
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Quoting 1490. Walshy:


Please don't quote "it".


What's "it" and why shouldn't I quote?
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1491. docrod
Quoting 1451. stormpetrol:
Anyone knows what sauce is best with crow? I need some! :))


I would suggest Mango Chutney.
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1490. Walshy
Quoting FunnelVortex:


These waves tend to have bursts of convection and weaken for a while, it's a cycle.


Please don't quote "it".
Member Since: May 17, 2009 Posts: 2 Comments: 907
1489. 19N81W
as suspected doesn't look very impressive tonight
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Quoting 1485. hurricanes2018:
cloud top are warming now..on invest97L ITS NOT LOOKING GOOD AT ALL.


These waves tend to have bursts of convection and weaken for a while, it's a cycle.
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DMIN has been pretty hard on it. So far no signs of a rebound; quite the opposite in fact, with convection declining faster with each new frame.

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Starts tomorrow morning 6:15 AM EDT


SENIOR DUTY METEOROLOGIST NWS ADMINISTRATIVE MESSAGE
NWS NCEP CENTRAL OPERATIONS COLLEGE PARK MD
2132Z SUN SEP 01 2013

A GOES-EAST RSO WILL BE IN OPERATION FROM 02/1015Z TO 03/1015Z TO
HELP MONITOR TROPICAL DEVELOPMENT EAST OF THE CENTRAL LESSER
ANTILLES
Member Since: September 23, 2005 Posts: 15 Comments: 11341
cloud top are warming now..on invest97L ITS NOT LOOKING GOOD AT ALL.
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Quoting 1470. Doppler22:
If anyone is tired of waiting on 97L and you want a break, the movie Twister is on CMT. I love this movie :p


Neat. Speaking of tornadoes on TV, I saw an interesting episode of Criminal Minds which revolved around tornadoes once.
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Latest sfc map shows the twave higher in latitude and extremely tilted sw to ne, but with the low still moving directly west from the southern end of the wave axis.

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Quoting 1453. prcane4you:
Is that means more convection to help intensifies 97L?
Yes, but it would take more time to consolidate the two lows, thereby slowing the intensification process.
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Quoting 1466. BahaHurican:
Seems the ULL is having more of an impact than some anticipated. During Dmax this a.m. I doubt it was as obvious....


KIcked in the chin now then yanked by the hair by "mega-trof" 9/4 - 9/5.
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Hey, where are you going? Jump over...
No se atreve a brincar las Antillas....

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Quoting 1472. eyewallblues:
Are those darts on their tables?
LOL, those would be clipboards.
Member Since: September 2, 2009 Posts: 130 Comments: 21194
1478. Walshy
Quoting Doppler22:
If anyone is tired of waiting on 97L and you want a break, the movie Twister is on CMT. I love this movie :p


Nice. Breaking Bad is on at 9 the blog should be a ghost town then.
Member Since: May 17, 2009 Posts: 2 Comments: 907
Quoting 1469. GTstormChaserCaleb:


Woah. Anything on a possible tack into Florida?
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invest 97L is going to weak invest and will not be a tropical d anytime soon in the next 24 hours.
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1475. ackee
Quoting 1454. TropicalAnalystwx13:
Stewart stated in the 2pm TWO that a westward track was likely over the next few days; NHC TAFB shows the storm southeast of Jamaica in 72 hours. Pasch comes in and says it's likely to track near or over Hispaniola in a few days. Not sure why the discrepancy, but I doubt Pasch ends up right.
agree if 97L is to track over Hispaniola it would have to straighten quite quickly over the Eastern Caribbean which I have a hard time seeing
Member Since: July 15, 2008 Posts: 0 Comments: 1376
Quoting 1465. Hurricanes305:


LMAO!!! Avila is on his tippy toes XD. While I never though a guy name Stacy would look like that.
Explain to me why he stood in the back... lol... and if u were named Stacy, you'd have muscles too... lol

[I know it's combat related stuff, but I couldn't resist...]
Member Since: October 25, 2005 Posts: 19 Comments: 22725
Quoting 1466. BahaHurican:
Seems the ULL is having more of an impact than some anticipated. During Dmax this a.m. I doubt it was as obvious....

Not really.

ULLs continue to ventilate.

Member Since: July 6, 2010 Posts: 113 Comments: 32802
Quoting 1450. MiamiHurricanes09:
Doubt it. Stacy will throw some punches, no hesitation. ;)



Pictured from left to right: Jack Beven, John Cangialosi, Eric Blake, Todd Kimberlain, Richard Pasch, Robbie Berg, Lixion Avila, James Franklin, Michael Brennan, Daniel Brown and Stacy Stewart.
Are those darts on their tables?
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Quoting 1467. Patrap:




:)))
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If anyone is tired of waiting on 97L and you want a break, the movie Twister is on CMT. I love this movie :p
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1468. ackee
I think if 97L does not develop now I don't see it trying again until 70W which I think would be the worst case scenario , if 97L takes this path and reach western Caribbean and end into the GOM we could see our first cane of the seasons I just dont see any development from 97L in the Eastern Caribbean just my take on 97L
Member Since: July 15, 2008 Posts: 0 Comments: 1376
1467. Patrap
Quoting 1464. stormpetrol:
I still 97L is doing better than most think, just my take, watch and see it will blooming in the morning again.


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Quoting 1462. Kowaliga:
Gettin' kicked in the chin by ULL over Haiti...

Seems the ULL is having more of an impact than some anticipated. During Dmax this a.m. I doubt it was as obvious....
Member Since: October 25, 2005 Posts: 19 Comments: 22725
Quoting 1450. MiamiHurricanes09:
Doubt it. Stacy will throw some punches, no hesitation. ;)



Pictured from left to right: Jack Beven, John Cangialosi, Eric Blake, Todd Kimberlain, Richard Pasch, Robbie Berg, Lixion Avila, James Franklin, Michael Brennan, Daniel Brown and Stacy Stewart.


LMAO!!! Avila is on his tippy toes XD. While I never though a guy name Stacy would look like that.
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I still 97L is doing better than most think, just my take, watch and see it will blooming in the morning again.
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Lixion is not as conservative as some think. He does, however, seem to require a little more in the way of factual evidence to go out on a limb than, say, the average WUnderblogger....

;o)
Member Since: October 25, 2005 Posts: 19 Comments: 22725
Gettin' kicked in the chin by ULL over Haiti...

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Interesting HWRF, GFDL, and GFS agreeing on track.

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Quoting 1456. prcane4you:
I don't see TrollTrackerScott there.I missed him.


Scott is not a troll.
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Quoting 1450. MiamiHurricanes09:
Doubt it. Stacy will throw some punches, no hesitation. ;)



Pictured from left to right: Jack Beven, John Cangialosi, Eric Blake, Todd Kimberlain, Richard Pasch, Robbie Berg, Lixion Avila, James Franklin, Michael Brennan, Daniel Brown and Stacy Stewart.
Robbie Berg is having a big year.....but when the last wave is played....Lixion Avila stands to win his 6th title in a row.
Member Since: Posts: Comments:
Quoting 1454. TropicalAnalystwx13:
Stewart stated in the 2pm TWO that a westward track was likely over the next few days; NHC TAFB shows the storm southeast of Jamaica in 72 hours. Pasch comes in and says it's likely to track near or over Hispaniola in a few days. Not sure why the discrepancy, but I doubt Pasch ends up right.
Unless it strengthens like the HWRF and GFDL says it will.
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Quoting 1450. MiamiHurricanes09:
Doubt it. Stacy will throw some punches, no hesitation. ;)



Pictured from left to right: Jack Beven, John Cangialosi, Eric Blake, Todd Kimberlain, Richard Pasch, Robbie Berg, Lixion Avila, James Franklin, Michael Brennan, Daniel Brown and Stacy Stewart.
I don't see TrollTrackerScott there.I missed him.
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Quoting 1434. Tropicsweatherpr:


Who is more conservative,Avila or Pasch?
Pasch is. When he and Bevin are on, a 50 mph TS could be construed as a DB or LO....
Member Since: October 25, 2005 Posts: 19 Comments: 22725

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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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