Invest 94L and the Lesser Antilles

By: Dr. Jeff Masters , 9:51 AM GMT on August 30, 2009

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Hi, this is Dr. Rob Carver filling in for Dr. Masters. The convection associated with Invest 94L has intensified, prompting the NHC to issue an early Tropical Weather Outlook to update the situation. Essentially, people in the Lesser Antilles need to start paying attention to the seas and skies. Looking at the computer track models, the set of model solutions are fairly similar to the Saturday model runs. A set of dynamical models (GFDL, HWRF, NOGAPS) runs to the NE of the Antilles, while the simpler models (LBAR, BAM family) are more easterly and take 94L over the Antilles. I do not ascribe any significance to the 00Z GFS track following the simpler models over the dynamical models. From my examination of the 00Z GFS run, it looks like the simulated 94L weakens too much, so the automatic vortex tracker picks up another vorticity feature. As for the future of 94L, there is a large area of large wind shear to it's north. It will need to keep it's track at WNW-W for intensification.

Update at 6AM EDT
I would be remiss if I didn't mention the major hurricane in the Eastern Pacific, Jimena At this time, Jimena has a satellite-estimated maximum wind speed of 115 mph, making it a Category 3 storm on the Saffir-Simpson scale. Jimena has an impressive presentation in satellite imagery with a large area of cold anvil cirrus in the center of the storm. The following microwave imagery indicate the formation of a relatively potent central eyewall, which is responsible for intensification.


Fig. 1 SSMI 85 GHz PCT at 0244Z Aug 30. Image courtesy of NRL.


People along the western coast of Mexico and along along the Baja need to pay close attention to this dangerous storm. I emphasize that using the current track and intensity forecast, Jimena will be a Category 4 storm when it approaches the tip of Baja and a Category 3 storm when it makes landfall up the coast.

It is worth noting that if Jimena follows the more easterly tracks presented in the computer track forecasts, the remnants of Jimena could impact NM and western Texas.


I'll update this entry further in response to 94L's development.


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http://weather.unisys.com/gfs/5d/gfs_pres_5d.gif

Shows a weak Tropical Depression hitting the Eastern Seaboard - 94L anyone?
Member Since: Posts: Comments:
307. jipmg
Quoting BahaHurican:
Hmmm..... this sounds like westward motion across the Caribbean longitudes (60W - 80W) followed by recurve across the US somewhere. Typical pattern, in fact, for this time of year. So this looks like another potential threat to the Antilles, and possibly even the Bahamas / Yucatan.


how does it go from the Yucatan to the bahamas?
Quoting homelesswanderer:


Morning All. I posted this last night. Sorry don't know how else to explain it. Futuremet, according to my local NWS they seem to agree with a ridge over the east coast. I dont know how to read your model so I can't tell will this ridge be eroded by yet another trough? Or does it look like a pattern shift? Thanks.


A RATHER STRONG 1025MB HIGH IS EXPECTED TO SETTLE OVER THE NRN MS
VALLEY AND GREAT LAKES REGION FOR MUCH OF THE UPCOMING
WEEK...RIDGING WELL SOUTH INTO LA AND ERN TX.
A QUIET WEATHER
PATTERN LOOKS TO BE IN PLACE MONDAY THROUGH THURSDAY. LOWER
DEWPOINTS WILL PROVIDE FOR MORE COMFORTABLE CONDITIONS...WITH
COOLER THAN NORMAL MINIMUMS DURING THE EARLY MORNING HOURS. AFTN
HIGHS WILL CONTINUE TO BE WARM WITH TEMPS IN THE UPPER 80S TO LOWER
90S.

LOW LEVEL MOISTURE WILL BEGIN TO INCREASE AGAIN LATE IN THE WEEK
AS THE HIGH SHIFTS EAST AND SOUTHERLY WINDS RETURN.
THIS WILL
BRING A SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS FRIDAY INTO
SATURDAY.
Hmmm..... this sounds like westward motion across the Caribbean longitudes (60W - 80W) followed by recurve across the US somewhere. Typical pattern, in fact, for this time of year. So this looks like another potential threat to the Antilles, and possibly even the Bahamas / Yucatan.
Member Since: Posts: Comments:
305. jipmg
Quoting StormFreakyisher:

The thing is, how far west will it go when it passes the Antilles?Will it go west as much to affect the East coast or smack right into Florida?


Wayy too far off to know if its even going to affect the east coast
72hr position:

Member Since: Posts: Comments:
BTW guys, Jimena was Invest 93L in the Atlantic. Just thought that was interesting to see that 93L developed.
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nrti,

I have said it before, and will say it again I am sure. Your ability and willingness to share the detailed information that many of us are either too busy, stubborn, or lazy to go find on our own; and share it in a way that most can understand is one of the things that really makes this blogosphere a productive learning environment.
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Quoting TampaSpin:
Morning all! Looks like 94L made a nice recovery as expected.


Woop TampaSpin is here (:

the NHC site has gone down, on safari I get this message:
Safari can’t open the page. Safari could not open the page “http://nhc.noaa.gov/” because the server is not responding
Member Since: Posts: Comments:
Quoting TampaSpin:
Morning all! Looks like 94L made a nice recovery as expected.


what is your thinking regarding track?
Member Since: Posts: Comments:
Quoting Drakoen:
I see that 94L is moving fully to the WNW. I expect the system to gradually take on a motion between WNW and NW placing it just north of the islands.
The system convection has improved dramatically over night as several of us noted the improved structure last night to aid in development with a good diurnal maximum.


Drak, What do you think of the NWS reports of a series of lows late next week which would move any systems out to sea? If 94L stays further south, this may not help. Do you place any credence on their outlook. I realize it is too early for a forecast, just and educated guess would suffice.
Member Since: Posts: Comments:
Morning all! Looks like 94L made a nice recovery as expected.
Member Since: September 2, 2007 Posts: 178 Comments: 20439
Quoting SQUAWK:


Have you not yet figured out what a troll look like?


I have, but I give other users a chance.

Another post like the others the user in question has done, and he becomes the first on my ignore list.
Member Since: Posts: Comments:
Quoting foggymyst:
Does anyone know the time frame for when 94L would be near the Antilles? Thanks.


2-3 days
Member Since: Posts: Comments:
Does anyone know the time frame for when 94L would be near the Antilles? Thanks.
Member Since: Posts: Comments:
Quoting StormJunkie:
Thanks NRTI, greatly appreciated!


No problem SJ. I don't know if you noticed but NHC has updated their model descriptions page. Excerpt for the BAMs

A divergence of the three versions of the BAM indicates varying steering flow within the parent GFS model. Hence, spread among the three versions of the BAM also serves as a rough estimate of the vertical shear as well as the complexity and uncertainty in the track forecast.
Member Since: Posts: Comments:
Quoting IpswichWeatherCenter:


Please listen to me about Caps Lock.

and The Weather Channel shouldn't be listened to ahead of the NWS


Have you not yet figured out what a troll look like?
Member Since: Posts: Comments:
Quoting BahaHurican:
Wouldn't be surprised to see it happen. Environment's supposed to be conducive to strengthening for the next 24 - 36. NHC is expecting it to make cat 4, and I'd guess strong cat 4 at that.

Best looking African initiated cyclone I've seen so far this season.


The NHC needs to issue Tropical Storm Watches for the Mexican Coast's, will they send in recon?
Member Since: Posts: Comments:
SOMETHING WORTH MENTIONING. NAM12 TAKES SFC LOW THATS EXPECTED TO
DEVELOP TODAY AND BRINGS IT ACROSS THE NORTHERN GULF. THE PLUS TO
THIS SOLUTION IS THAT THE LOW CONTINUES TO MOVE AWAY FROM THE AREA
AND REACHES THE WEST CENTRAL FLORIDA COAST BY TUESDAY. THE LOW THEN
STALLS JUST OFF THE COAST AS THE UPPER TROUGH CONTINUES TOWARDS THE
US EAST COAST. WHAT WILL HAPPEN FROM THIS POINT IS STILL IN QUESTION
BUT ITS NOT OUT OF THE REALM OF POSSIBILITIES FOR THIS FEATURE TO BE
SOMETHING OF CONCERN AT SOME POINT IN THE FUTURE SO WILL CONTINUE
TO MONITOR.
Member Since: Posts: Comments:
Quoting StormJunkie:


Hey Grothar

I hear you, the times of model output combined with the various delays in imagery updates can get confusing. These learning videos on how to use some of the better model pages goes in to a some detail about the timing of model runs and UTC time.

I also find the GHCC site useful as it shows both UTC and your local time side by side. NHC imagery site does so as well.


Thanks, good little links. No wonder even the experts get confused. Any idea about the high building back in later in the week, which might steer the system further to the west? I may have missed it if someone mentioned it earlier. I am getting tired of hitting my Refresh button.
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Quoting jipmg:


If the high strengthens, then I see "WNW" "NW" (as a strong TS or hurricane) then back WNW, and shifting from WNW to W.

SHIPS and I beleive a couple of models are turning 94L into a hurricane

The thing is, how far west will it go when it passes the Antilles?Will it go west as much to affect the East coast or smack right into Florida?
Member Since: Posts: Comments:
The guy at Crown Weather said the shear to the N of 94L is creating an outflow channel. He also said an immediate turn to the NW as the models indicate is not going to happen.WNW for 3 to 5 days. He expects 94L to effect the lesser antillies.
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i think 94L will be close to the bamm model.
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Quoting P451:


You're not kidding! Wow is right.

And it has a pinhole eye!
Member Since: Posts: Comments:
278. jipmg
Quoting AllStar17:
It currently appears 94L will go just to the north of the islands, and after that, the track becomes uncertain....but it appears it may turn back towards the west.


If the high strengthens, then I see "WNW" "NW" (as a strong TS or hurricane) then back WNW, and shifting from WNW to W.

SHIPS and I beleive a couple of models are turning 94L into a hurricane
Quoting jipmg:


This is going straight to a 5
Wouldn't be surprised to see it happen. Environment's supposed to be conducive to strengthening for the next 24 - 36. NHC is expecting it to make cat 4, and I'd guess strong cat 4 at that.

Best looking African initiated cyclone I've seen so far this season.
Member Since: Posts: Comments:
Jimena MIMIC
Member Since: August 2, 2006 Posts: 46 Comments: 11666
Quoting futuremet:


The models show the Bermuda high...not really the Azores high strengthening, as a ridge start developing in the east coast by Saturday.

ECMWF

NCEP ensemble mean


The Azores high should not be that strong, since we are converting into a negative NAO. This may also mean less SAL.

ECMWF-GFS 240hr mean

An aggressive high will proliferate over the east coast.



Morning All. I posted this last night. Sorry don't know how else to explain it. Futuremet, according to my local NWS they seem to agree with a ridge over the east coast. I dont know how to read your model so I can't tell will this ridge be eroded by yet another trough? Or does it look like a pattern shift? Thanks.


A RATHER STRONG 1025MB HIGH IS EXPECTED TO SETTLE OVER THE NRN MS
VALLEY AND GREAT LAKES REGION FOR MUCH OF THE UPCOMING
WEEK...RIDGING WELL SOUTH INTO LA AND ERN TX.
A QUIET WEATHER
PATTERN LOOKS TO BE IN PLACE MONDAY THROUGH THURSDAY. LOWER
DEWPOINTS WILL PROVIDE FOR MORE COMFORTABLE CONDITIONS...WITH
COOLER THAN NORMAL MINIMUMS DURING THE EARLY MORNING HOURS. AFTN
HIGHS WILL CONTINUE TO BE WARM WITH TEMPS IN THE UPPER 80S TO LOWER
90S.

LOW LEVEL MOISTURE WILL BEGIN TO INCREASE AGAIN LATE IN THE WEEK
AS THE HIGH SHIFTS EAST AND SOUTHERLY WINDS RETURN.
THIS WILL
BRING A SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS FRIDAY INTO
SATURDAY.
Member Since: Posts: Comments:
It currently appears 94L will go just to the north of the islands, and after that, the track becomes uncertain....but it appears it may turn back towards the west.
Member Since: Posts: Comments:
Hey, everyone!

Been a while since I've been on. 94L made a pretty big comeback. But, it still has to get a little more organized with its convection, and fix its LLC.

I've been looking at the super long-range CFS models. Oh IKE, expect rain on May 31st. LOL.
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Thanks NRTI, greatly appreciated!
Member Since: Posts: Comments:
Quoting WRONGASUSUALTHISYEAR:
I JUST WATCHED THE TROPICAL UPDATE ON THE WEATHER CHANNEL AND THEY ARE SAYING THAT THERE ARE 3 COLD FRONTS THAT ARE PUSHING DOWN FROM CANADA THAT WILL PUSH OFF THE ENTIRE EAST COAST USA EVERY 3 DAYS OR SO KEEPING TROPICAL SYSTEMS AWAY FROM THE EAST COAST USA OVER THE NEXT FEW WEEKS SO THERE GO WATCH FOR YOURSELVES


Please listen to me about Caps Lock.

and The Weather Channel shouldn't be listened to ahead of the NWS
Member Since: Posts: Comments:
269. jipmg
Quoting IpswichWeatherCenter:


I'd put my money on a Cat 5, I don't want it to occur, but its probably right.


yep, when you get a small eye like that form, the pressure drops like a rock
000
WHXX01 KMIA 301234
CHGE77
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1234 UTC SUN AUG 30 2009

DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.

EAST PACIFIC OBJECTIVE AIDS FOR

TROPICAL CYCLONE JIMENA (EP132009) 20090830 1200 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
090830 1200 090831 0000 090831 1200 090901 0000

LAT LON LAT LON LAT LON LAT LON
BAMS 16.0N 106.0W 16.9N 107.3W 17.8N 108.4W 19.0N 109.7W
BAMD 16.0N 106.0W 17.1N 106.9W 18.2N 107.8W 19.7N 108.7W
BAMM 16.0N 106.0W 16.9N 107.0W 17.9N 107.8W 19.4N 109.0W
LBAR 16.0N 106.0W 17.0N 107.2W 18.2N 108.8W 19.7N 110.6W
SHIP 115KTS 127KTS 128KTS 123KTS
DSHP 115KTS 127KTS 128KTS 123KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
090901 1200 090902 1200 090903 1200 090904 1200

LAT LON LAT LON LAT LON LAT LON
BAMS 20.7N 111.0W 23.4N 113.2W 24.7N 115.6W 24.9N 116.7W
BAMD 21.6N 109.4W 25.3N 110.2W 26.9N 109.6W 26.5N 108.3W
BAMM 21.3N 110.0W 24.8N 111.7W 26.4N 113.2W 26.8N 113.6W
LBAR 21.7N 112.5W 26.5N 115.7W 30.9N 115.7W 31.9N 111.4W
SHIP 114KTS 92KTS 64KTS 36KTS
DSHP 114KTS 81KTS 52KTS 32KTS

...INITIAL CONDITIONS...
LATCUR = 16.0N LONCUR = 106.0W DIRCUR = 300DEG SPDCUR = 8KT
LATM12 = 15.4N LONM12 = 104.7W DIRM12 = 302DEG SPDM12 = 10KT
LATM24 = 14.2N LONM24 = 102.9W
WNDCUR = 115KT RMAXWD = 10NM WNDM12 = 90KT
CENPRS = 948MB OUTPRS = 1009MB OUTRAD = 150NM SDEPTH = D
RD34NE = 60NM RD34SE = 60NM RD34SW = 50NM RD34NW = 60N
Member Since: Posts: Comments:
Quoting WPBHurricane05:
Cat 4:

30/1200 UTC 16.0N 105.9W T6.0/6.0 JIMENA -- East Pacific


I'd put my money on a Cat 5, I don't want it to occur, but its probably right.
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Quoting StormJunkie:
Morning nrti, good to see you as always!

That is a little over my head, I just like to pretend I know what I am talking about...And I didn't even stay in a HIE last night :)

Seriously though...What you are saying is that a deeper system would be kept more southerly because of the direction of the shear?


Or a shallower system would go more northerly, since it would not "see" the shear.
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Quoting Weather456:


wow, glad to see you know our nationality.

well my island is the 2nd most affected country in the Caribbean when it comes to hurricanes. Only behind Cuba. I'm 21 and I'ved lived through 6 majors, and a few other hurricanes and tropical storms.

Those 6 are

Hugo
Luis
Marilyn
Georges
Lenny
Omar


No two hurricanes are alike.
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Quoting WRONGASUSUALTHISYEAR:
CLAUDETTE WAS NO WORSE THEN TYPICAL EVERYDAY RAIN STORMS IN FLORIDA AND BILL AND ANA DIDNT HIT THE USA AND 94L WONT BE ANYTHING EITHER ITS DOING THE SAME THING THE OTHER STORMS DID UP AND DOWN UP AND DOWN FALL APART THEN BUILD A LITTLE THEN FALL APART AND FISH FISH FISH THE EAST COAST TO MANY FRONTS COMMING DOWN TO HIT ANYWHERE ON THE EAST COAST


Do me 1 favour, STOP USING CAPS LOCK.
Member Since: Posts: Comments:
I see that 94L is moving fully to the WNW. I expect the system to gradually take on a motion between WNW and NW placing it just north of the islands.
The system convection has improved dramatically over night as several of us noted the improved structure last night to aid in development with a good diurnal maximum.
Member Since: Posts: Comments:
Cat 4:

30/1200 UTC 16.0N 105.9W T6.0/6.0 JIMENA -- East Pacific
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Quoting WetBankGuy:
I've been away all week and suddenly WRONGASUSUAL is on hide. Does the system know who this is, or if another people vote him down does it hide that poster from everyone?



He's trolling bad today on 'WRONGAGAINASUSUAL'
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Quoting Grothar:
TO: Weather456

My quote button is not working this morning.

So a Kittitian, eh? Been there, beautiful island. We stayed at the Four Season, ever heard of it. That is why, many storms which have affected your area, may often affect us. Just concerned about the current models, not paranoid. Enjoy your input.


wow, glad to see you know our nationality.

well my island is the 2nd most affected country in the Caribbean when it comes to hurricanes. Only behind Cuba. I'm 21 and I'ved lived through 6 majors, and a few other hurricanes and tropical storms.

Those 6 are

Hugo
Luis
Marilyn
Georges
Lenny
Omar
Member Since: Posts: Comments:

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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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