Lesser Antilles Disturbance 97L a Threat to Develop

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

Share this Blog
70
+

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

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: 1355 - 1305

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 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50Blog Index

1355. KEEPEROFTHEGATE (Mod)
Quoting 1350. weatherlover94:
I do think we will go into Red mode at 8:00
I will say 40 60
Member Since: Posts: Comments:
Quoting 1346. scott39:
exactly!



But I think it will get together before then. My worry now is where it goes after 5 days and how strong it will be
Member Since: Posts: Comments:
Quoting 1316. Ameister12:
Despite going through D-Min with no lower convergence, 97L is doing pretty decent.
Convection is in reverse mode.
Member Since: June 23, 2011 Posts: 0 Comments: 1252
1352. LargoFl
SPSMLB

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MELBOURNE FL
653 PM EDT SUN SEP 1 2013

FLZ041-044-046-141-147-012345-
COASTAL VOLUSIA COUNTY-INLAND VOLUSIA COUNTY-NORTHERN BREVARD
COUNTY-NORTHERN LAKE COUNTY-SEMINOLE-
653 PM EDT SUN SEP 1 2013

...A SIGNIFICANT WEATHER ADVISORY IS IN EFFECT FOR STRONG WIND GUSTS
AND SMALL HAIL OVER NORTHWESTERN BREVARD COUNTY...NORTHEASTERN LAKE
COUNTY...SEMINOLE COUNTY...SOUTHERN VOLUSIA COUNTY...

* UNTIL 745 PM EDT.

AT 651 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STORM CAPABLE OF PRODUCING STRONG WINDS AND SMALL HAIL OVER
MAYTOWN...MOVING NORTHEAST AT 15 MPH.

LOCATIONS IN THE PATH OF THE STORM WHICH MAY EXPERIENCE STRONG WINDS
AND SMALL HAIL INCLUDE APOLLO BEACH...SCOTTSMOOR...AND BETHUNE BEACH.

ADDITION STRONG STORMS WITH GUSTY WINDS WILL CONTINUE TO PUSH
THROUGH SEMINOLE COUNTY INTO SOUTHERN VOLUSIA COUNTY. THESE STORMS
WILL AFFECT SANFORD...DELTONA...LAKE MONROE...DEBARY...AND DELAND.

THE PRIMARY THREAT WILL BE CLOUD TO GROUND LIGHTNING STRIKES AND
GUSTY WINDS UP TO 55 MPH...WHICH CAN CAUSE UNSECURED OBJECTS TO BLOW
AROUND...SNAP TREE LIMBS...CAUSE POWER OUTAGES OR CAPSIZE SMALL
BOATS. HEAVY RAINFALL WILL TEMPORARILY REDUCE VISIBILITY. SEEK
SHELTER INDOORS UNTIL THE STORM PASSES.

BOATERS SHOULD BE AWARE THAT STRONG WIND GUSTS SOMETIMES OCCUR WELL
AWAY FROM THE HEAVY RAIN AND LIGHTNING ASSOCIATED WITH STORMS.

LAT...LON 2869 8065 2876 8074 2885 8078 2885 8081
2868 8069 2866 8079 2869 8079 2872 8075
2877 8084 2866 8082 2861 8112 2861 8132
2864 8133 2864 8146 2871 8146 2878 8141
2879 8153 2907 8161 2921 8099
TIME...MOT...LOC 2252Z 228DEG 13KT 2885 8094
Member Since: Posts: Comments:
1351. hydrus
Quoting 1334. sunlinepr:
You see that upper low moving across Hispaniola.? I cannot remember the year, but I saw one do that same thing, and the interaction with land helped bring the system to the surface and it became a tropical storm. I wish I could remember the name.
Member Since: Posts: Comments:
I do think we will go into Red mode at 8:00
Member Since: Posts: Comments:
Quoting 1312. MiamiHurricanes09:
Since we're talking analogs, I think Hurricane Charlie is a great contender. It remained a moderate tropical storm until it reached the northwestern Caribbean where it intensified into a major hurricane.

That could very well be the scenario with 97L if it moves into the northwestern Caribbean as an organized tropical cyclone.

I think Charley is the extreme I think a Fay(08) or Ernesto(06) like storm is more likely
Charley also stayed south and the models I've seen show 97L going into the islands
Member Since: Posts: Comments:
Quoting 1332. scott39:
I saw that one and the next run after it heading to the N Texas Coast.


hmmm, interesting. Course I realize this isn't written in stone and probably will change. I don't know. I would be surprised if TX actually got something. Not that I am wishing a major hurricane because I am not. Just a good rain maker for TX
Member Since: Posts: Comments:
Quoting 1321. Articuno:

Hurricane Charlie or Charley?
*Charley.
Member Since: Posts: Comments:
1346. scott39
Quoting 1344. LargoFl:
it has a whole week to get its act together,still early yet
exactly!
Member Since: Posts: Comments:
Quoting 1338. DonnieBwkGA:


extreme high chance or extreme low chance?



High chance
Member Since: Posts: Comments:
1344. LargoFl
Quoting 1342. scott39:
You cant have a TC without lower convergence. 97L is going to have to work for it.
it has a whole week to get its act together,still early yet
Member Since: Posts: Comments:
Quoting 1337. ncstorm:
Frank Strait Fan Club
2 minutes ago

It also appears to be developing a good outflow pattern with cirrus spreading out. Probably is in the process of developing.

Going to say the Northern outflow is excellent with 97L. Needs to work on other sides.
Member Since: July 7, 2005 Posts: 0 Comments: 5396
1342. scott39
You cant have a TC without lower convergence. 97L is going to have to work for it.
Member Since: Posts: Comments:
Quoting 1336. Seflhurricane:
Going to be an interesting TWO



Yes it sure is
Member Since: Posts: Comments:
Quoting 1303. stormpetrol:


I think its near 15N/62W, just my take though, within a degree either way.
Up,down.Seesaw 97L
Member Since: June 23, 2011 Posts: 0 Comments: 1252
Quoting 1328. HurricaneAndre:
What does that date say.


Strong TS or cat 1 in the Western GOM
Member Since: Posts: Comments:
Quoting 1327. Articuno:

I think this has a extreme chance of becoming the first hurricane of the season.


extreme high chance or extreme low chance?
Member Since: June 29, 2013 Posts: 34 Comments: 2332
1337. ncstorm
Frank Strait Fan Club
2 minutes ago

It also appears to be developing a good outflow pattern with cirrus spreading out. Probably is in the process of developing.
Member Since: Posts: Comments:
Going to be an interesting TWO
Member Since: Posts: Comments:
1335. KEEPEROFTHEGATE (Mod)
Quoting 1329. scott39:
97L will more than likely stay disorganized for the next 48 to 72 hours.
that's what iam figuring till 69 w when it should take off if that's what its going to do
Member Since: Posts: Comments:
Member Since: Posts: Comments:
1333. LargoFl
Quoting 1322. TexasHurricane05:
Saw this the other day...any models still hinting at this?

here is the latest from NHC on it...........OTHER SYSTEMS WITH FORMATION POTENTIAL BEYOND 48 HOURS...

A TROPICAL WAVE IS FORECAST TO MOVE ACROSS THE YUCATAN PENINSULA
AND INTO THE BAY OF CAMPECHE IN A COUPLE OF DAYS WHERE ENVIRONMENTAL
CONDITIONS ARE EXPECTED TO BECOME MARGINALLY FAVORABLE FOR
DEVELOPMENT. THIS SYSTEM HAS A LOW CHANCE...NEAR 0 PERCENT...OF
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS...AND A LOW
CHANCE...20 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE
NEXT 5 DAYS...AS IT MOVES WEST-NORTHWESTWARD AT 10 MPH.

FIVE-DAY FORMATION PROBABILITIES ARE EXPERIMENTAL IN 2013. COMMENTS
ON THE EXPERIMENTAL FORECASTS CAN BE PROVIDED AT...

HTTP://WWW.NWS.NOAA.GOV/SURVEY/NWS-SURVEY.PHP?COD E=ETWO

FORECASTER STEWART

Member Since: Posts: Comments:
1332. scott39
Quoting 1322. TexasHurricane05:
Saw this the other day...any models still hinting at this?

I saw that one and the next run after it heading to the N Texas Coast.
Member Since: Posts: Comments:
1331. FOREX
Quoting 1329. scott39:
97L will more than likely stay disorganized for the next 48 to 72 hours.


looking that way.
Member Since: Posts: Comments:
Quoting LargoFl:


Nonsence..lets try to get a developed cyclone before putting any faith in those intensity models. As of now this thing remains disorganized with not much in the lower levels to keep generating convection 0 convergence. might still develope but its certainly not doing so now.
Member Since: Posts: Comments:
1329. scott39
97L will more than likely stay disorganized for the next 48 to 72 hours.
Member Since: Posts: Comments:
Quoting 1322. TexasHurricane05:
Saw this the other day...any models still hinting at this?

What does that date say.
Member Since: Posts: Comments:
Quoting 1307. LargoFl:

I think this has a extreme chance of becoming the first hurricane of the season.
Member Since: Posts: Comments:
1326. ncstorm
Frank Strait Fan Club
... and vis sat shows W flow on south side of main cloud mass. Recon should be in there if it isn't.
Member Since: Posts: Comments:
1325. JNTenne
Quoting 1313. Tazmanian:



that's have not been updated sices 2am and on top of that the NHC has drop 96L
Geesh I hate posting old info.. aplogeeze..
Member Since: Posts: Comments:
Blog has suddenly "weakened" lol
Member Since: Posts: Comments:
1323. KYDan
Quoting weatherlover94:



EE



EIEIO
Member Since: Posts: Comments:
Saw this the other day...any models still hinting at this?

Member Since: Posts: Comments:
Quoting 1312. MiamiHurricanes09:
Since we're talking analogs, I think Hurricane Charlie is a great contender. It remained a moderate tropical storm until it reached the northwestern Caribbean where it intensified into a major hurricane.

That could very well be the scenario with 97L if it moves into the northwestern Caribbean as an organized tropical cyclone.

Hurricane Charlie or Charley?
Member Since: Posts: Comments:
Quoting 1293. GTstormChaserCaleb:
End of the NAVGEM run:

Maybe a landfall in Yucatan or Belize.
Member Since: Posts: Comments:
1319. LargoFl
Member Since: Posts: Comments:
Quoting 1316. Ameister12:
Despite going through D-Min with no lower convergence, 97L is doing pretty decent.


D Min had little effect. I expect D Max to really bring it to life
Member Since: Posts: Comments:
Link

100 miles ENE of Martinique
Member Since: Posts: Comments:
Despite going through D-Min with no lower convergence, 97L is doing pretty decent.
Member Since: Posts: Comments:
1315. LargoFl
Nam for thursday..........
Member Since: Posts: Comments:
1314. LargoFl
Quoting 1312. MiamiHurricanes09:
Since we're talking analogs, I think Hurricane Charlie is a great contender. It remained a moderate tropical storm until it reached the northwestern Caribbean where it intensified into a major hurricane.

That could very well be the scenario with 97L if it moves into the northwestern Caribbean as an organized tropical cyclone.
oh boy i hope not,just with rain alone florida doesnt need anymore..add heavy winds oh boy the tree's...
Member Since: Posts: Comments:
Quoting 1310. JNTenne:
I just love the loop de loops 96L is forecasting...
Would not like to be on a boat anywhere near there next week!



that's have not been updated sices 2am and on top of that the NHC has drop 96L
Member Since: May 21, 2006 Posts: 5091 Comments: 115343
Since we're talking analogs, I think Hurricane Charlie is a great contender. It remained a moderate tropical storm until it reached the northwestern Caribbean where it intensified into a major hurricane.

That could very well be the scenario with 97L if it moves into the northwestern Caribbean as an organized tropical cyclone.
Member Since: Posts: Comments:


Well

LOOP
Member Since: Posts: Comments:
1310. JNTenne
I just love the loop de loops 96L is forecasting...
Would not like to be on a boat anywhere near there next week!
Member Since: Posts: Comments:
1309. scott39
I went 2 seasons on here not understanding maps. If you can get a general idea about what your looking at on the maps, then you can get a better idea on how close a TC is developing.... or not. Crown Weather.Com has some free good ones.
Member Since: Posts: Comments:
Quoting 1305. hurricanejunky:


This is probably the 4th rain event like this. The past two have been 2.77" or lower but this one is a new high in such a short span. 3.74" in less than two hours makes things rather WET! Good to see you too! Hope things are going well in your neck of the woods!
I'm just hoping I don't have to battening up by the end of the week... :/... I'm fairly sure we'll see a hurricane of some kind out of 97L, but I'm really, really hoping it makes it all the way to TX... it's about the only place along the potential track that wouldn't suffer from the rains a large system like 97L would bring...
Member Since: Posts: Comments:
1307. LargoFl
Member Since: Posts: Comments:
Quoting 1259. kmanislander:
Convergence gone again, just like same time yesterday.

No upgrade unless and until this system can maintain a decent state of organization. I bet that within 2 to 3 hours the deep convection refires again around 62W. Very frustrating following these weak disorganized lows.

LOL, patience is key with these things. Something I don't have.
Member Since: Posts: Comments:
Quoting 1298. BahaHurican:
This looks REAL familiar... everybody has had these heavy rains this summer...

Good to see u , junky.


This is probably the 4th rain event like this. The past two have been 2.77" or lower but this one is a new high in such a short span. 3.74" in less than two hours makes things rather WET! Good to see you too! Hope things are going well in your neck of the woods!
Member Since: Posts: Comments:

Viewing: 1355 - 1305

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 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50Blog 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
52 °F
Light Rain Mist