Ed DunhamAdministrator
(Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017))
Mon Aug 11 2008 03:45 PM
Watching Wave East of the Lesser Antilles

9PM EDT 13 August Update

The wave everyone is watching east of the Caribbean (92L) has not developed much today, and may not tomorrow, but is definitely worth keeping a watch on through the weekend it is the time of year where its prudent to watch. Those in Florida and the Southeastern US should take very close note on what this wave is doing over the next few days.

More immediately it may bring some showers to the northern lesser Antilles, and if it develops and doesn't get caught up in the Greater Antilles, could become a threat to the US early-mid next week. I would be watching the model trends closely over the next few days (see the model links below the article for animations, and more at the bottom and others on the Data Links.

Let us know what you think in the forecast lounge, a place for shooting the breeze about the storm (including discussion about the longer range models).

6:30 AM EDT 13 August Update

The basin is active, but nothing is imminent for development today it appears.

Not all that much has changed with the 92L situation since yesterday, it continues to move generally west northwest, and remains generally disorganized, being under some negative influences of shear. It appears this influence may go away at some point, so It may become a depression today. It more likely will not , however it still remains something to be watched for development based on model projections. If it does develop it will likely take some time.

93L to the east of it is also in a similar situation although that is much less likely to have any land impacts at this point.

12 August Update



92L remains the system to watch this week, both in the Leeward Islands and potentially here later, some models (such as the GFDL) put this system in the Bahamas in the weekend which could put the Southeast, the Gulf, or Florida potentially at risk sometime next week Then again, it appears the heading is wrong on the model initializations so it's likely its off a bit too much and would go further west (and south) than indicated.

These models are fairly inaccurate at long range and it does not mean it will do this, but could mean that this system should be monitored closely for the potential over the next several days. Let us know what you think in the forecast lounge

More to come as time progresses...
Mike

Original Update

Remembering that Invest areas are just tropical waves with some potential for additional development (and not 'sure things'), there is really nothing in the Atlantic basin to get concerned about yet. In modest to slightly above normal seasons it is not uncommon for an active July to be followed by a rather quiet August. Examples include 1944 (2 storms), 1966 (1 storm) and 1997 (none in August).

Invest 92L in the central Atlantic well east of the Windward Islands remains very disorganized near 11.6N 48.1W at 11/12Z. The wave is moving to the west northwest at 10-12 knots with most of the convection displaced to the west of the system because of easterly wind shear. The easterly shear should relax somewhat and give this system a small window of opportunity for additional development. If this development occurs (and thats a rather big IF at the moment), steering patterns would place the system near 19.5N 70.5W at 16/12Z moving to the west northwest to northwest at 7 knots. Winds are currently sustained at 20 knots with pressure at 1009MB. An active westerly shear zone from the Yucatan through the Caribbean Sea to the Windward Islands is not expected to change much in the next few days. By late Wednesday, the Invest 92L system will begin to encounter southwesterly wind shear as it approaches the Islands.

Invest 93L in the eastern Atlantic southwest of the Cape Verde Islands has active but disorganized convection near 10.8N 28.8W at 11/12Z. This tropical wave, with sustained winds of 25 knots and a pressure of 1008MB, is moving to the west at 15 knots. Steering patterns would place this system near 18N 51W at 16/12Z with movement to the west northwest at 12 knots.

An area of active convection persists in the southern Caribbean Sea just to the north of Panama and just to the south of the westerly shear zone mentioned above.

Invest 93L probably has the best chance for eventual slow development as it moves within an area of lighter wind shear. The NAO trends notwithstanding, the shear zones in the tropical north Atlantic remain uncommonly strong for this part of the season. Models are really fodder for the Forecast Lounge when the existing patterns of dry air and wind shear simply don't support some of the current model outputs. The recipe for a 'grain of salt' applies quite well here, but we'll keep an eye on these areas just in case the overall pattern should suddenly change.
ED

Lesser Antilles Radar Mosaic
{{StormCarib}}
{{StormLinks|92L|92|6|2008|1|92L}}
{{StormLinks|93L|93|7|2008|2|93L}}


danielwAdministrator
(Moderator)
Mon Aug 11 2008 04:45 PM
Re: Looking Around the Basin

Apparently the combination of the model runs and boredom has raised the eyebrows at TPC/ NHC.
RECON is tasked with an INVEST for tomorrow.

Latest SHIPS model has backed down a bit on the Max winds at 120 hours. Now down to 78kts... still a Hurricane.

93L now being run on SHIPS. Looks to be a lot higher in latitude than 92L.
Current 92L position is 11.6N/ 48.1W
93L forecast for nearly the same longitude is at 96hours. 15.6N/ 47.5W. That would make in roughly 4 degrees or 240nm north of 92L's location.

Early SHIPS on 93L look like a Fish Spinner!

NOUS42 KNHC 111530
WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1130 AM EDT MON 11 AUGUST 2008
SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)
VALID 12/1100Z TO 13/1100Z AUGUST 2008
TCPOD NUMBER.....08-072

I. ATLANTIC REQUIREMENTS
1. SUSPECT AREA (APPROCACHING THE LESSER ANTILLES)
FLIGHT ONE -- TEAL 70
A. 12/1800Z
B. AFXXX 01DDA INVEST
C. 12/1545Z
D. 14.0N 55.0W
E. 12/1730Z TO 12/2200Z
F. SFC TO 10,000 FT

FLIGHT TWO -- TEAL 71
A. 13/0600Z
B. AFXXX 02DDA CYCLONE
C. 13/0300Z
D. 15.0N 57.0W
E. 13/0500Z TO 13/0900Z
F. SFC TO 10,000 FT

2. OUTLOOK FOR SUCCEEDING DAY: BEGIN 6-HRLY FIXES AT
13/1800Z IF SYSTEM DEVELOPS AND IS A THREAT. NOAA PLANS
TO FLY TWO DOPPLER RADAR MISSIONS DEPARTING BARBADOS
AT 13/1800Z AND 14/0600Z.


cchsweatherman
(Weather Watcher)
Mon Aug 11 2008 05:13 PM
Re: Looking Around the Basin

Over the past few hours, I have been watching the surface circulation die with Invest 92L and a mid-level circulation becoming dominant at around 12.8 N and 50.3 W. Just watch the latest visible loops and you will see what I mean. It appears that Invest 92 is now attempting to form a new circulation center further north and west than the old surface circulation. This still needs to be watched as in the last few frames, convection has increased and become slightly better organized.

scottsvb
(Weather Master)
Mon Aug 11 2008 07:57 PM
Re: Looking Around the Basin

Its not north and west.. you mean east near 13.7N and 47.5W, The old center has weakened but there is still a weakening midlevel vortex where you said. I feel overtime the LLC mentioned above will be the main feature of intrest but still 2-3days away from St.Martaan (close to).

MichaelA
(Weather Analyst)
Mon Aug 11 2008 08:24 PM
Re: Looking Around the Basin

93L is looking much more robust than 92L this afternoon. If that continues, 93L may be named before 92L. Models are a bit interesting in their diversity right now. Some develop and some do not.

Unregistered User
(Unregistered)
Mon Aug 11 2008 08:38 PM
Re: Looking Around the Basin

There is a more distinct spin over the last few hours with 92L. Thunderstorms forming to the north and west of the circulation and building. May be mid level but its much more visible than this mourning. Still 24-48 hours away but I do see developing system.

Beach
(Weather Guru)
Mon Aug 11 2008 08:39 PM
Re: Looking Around the Basin

What is going on at 25-30N 55W ?

http://www.ssd.noaa.gov/goes/east/tatl/loop-wv.html

When you click on HDW-low does that box represent surface winds? I used the search feature at NOAA but it didn't find anything.


Beach
(Weather Guru)
Mon Aug 11 2008 08:48 PM
Re: Looking Around the Basin

Also...
Looking at the bouys from
31.98 N 69.65 W (31°58'42" N 69°38'56" W) to
24.00 N 70.99 W (23°52'1" N 70°52'12" W)

http://www.ndbc.noaa.gov/maps/Western_Atlantic.shtml

they have all been reporting winds from the S/SW all day


Freezey
(Verified CFHC User)
Mon Aug 11 2008 10:59 PM
Re: Looking Around the Basin

Besides 92L &93L whats up with this big Blod working its way up under Cuba? it seems to have a bit of circulation.

LoisCane
(Veteran Storm Chaser)
Tue Aug 12 2008 12:03 AM
Re: Looking Around the Basin

Having a problem trying to figure out what the timing is on these waves. On one level they barely look developed in any way. The convection on 92 is not near the center and some models had it slowing down as it approached the bahamas/cuba.. others seem to have dropped it.

Any input on what exactly might happen and if 92 will even last?

93 has more running room and 92 has helped wet the atmosphere up a bit for it.

Hard to have models coming so close to our part of the world and yet... nothing seems to be happening in a solid way.


danielwAdministrator
(Moderator)
Tue Aug 12 2008 03:23 AM
Discussion Excerpts

TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
227 PM EDT MON AUG 11 2008


A SURFACE LOW ASSOCIATES WITH THE WAVE ALONG 78W AND SOUTH OF
19N...WITH CIRCULATION AFFECTING THE FLOW PATTERN ACROSS
PANAMA/COSTA RICA...WHERE THE 12 UTC RAOB FROM MPCZ SHOWED A VERY
UNCOMMON WEST-SOUTHWEST LOW LEVEL FLOW. UNDER INFLUENCE OF THIS
FLOW THE EASTERN PACIFIC ITCZ IS NOW NORTH OF THE ISTHMUS INTO THE
SOUTHERN CARIBBEAN...AND THIS IS TO SUSTAIN HEAVY RAINFALL ACROSS
PORTIONS OF PANAMA INTO EASTERN COSTA RICA/NORTHEAST HONDURAS.
OVERALL EXPECT RAINFALL AMOUNTS OF 15-25MM/DAY AND MAXIMA OF
40-80MM. THROUGH 48-60 HRS EXPECT A SLIGHT DECREASE TO MAXIMA OF
30-60MM. UNDER FAVORABLE MJO CONDITIONS MODELS SUGGEST POSSIBILITY
OF THE SURFACE LOW PERSISTING/BECOMING BETTER ORGANIZED AS IT
TRACKS ALONG THE COAST OF CENTRAL AMERICA.

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
300 PM EDT MON AUG 11 2008

VALID 12Z THU AUG 14 2008 - 12Z MON AUG 18 2008

OUT EAST...THE 00Z ECMWF PHASED A SHORTWAVE MOVING THROUGH THE
DEEP SOUTH WITH THE CLOSED CYCLONE IN QUEBEC WITH DRAMATIC
CONSEQUENCES /AN AUGUST NOREASTER./ CONSIDERING THE EARLIER
PREFERENCE OF THE 00Z GFS...AFTER COORDINATING WITH OPC...DECIDED
TO SPLIT THE DIFFERENCE BETWEEN THE 00Z ECMWF AND 00Z GFS WITH
THIS FEATURE...JUST IN CASE...KEEPING IT A FLAT WAVE MOVING MORE
OFFSHORE NEW ENGLAND THAN ADVERTISED ON THE 00Z ECMWF. DOWN
SOUTH...THE LOW MOVING ACROSS CUBA INTO THE EASTERN GULF OF MEXICO
IS A CONTINUATION OF THE TROPICAL LOW COORDINATED BETWEEN HPC/TPC
AT NOON YESTERDAY...WHICH ALSO SPLITS THE DIFFERENCE BETWEEN THE
00Z GFS/CANADIAN/ECMWF SOLUTIONS.

PROGNOSTIC DISCUSSIONS FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
300 PM EDT MON AUG 11 2008

6-10 DAY OUTLOOK VALID FOR AUG 17 - 21 2008

...LAST NIGHT'S ECMWF MODEL RUN SHOWED A WEAKER TROUGH AND A
STRONGER BERMUDA HIGH OVER THE EAST, BUT THIS MODEL IS SEEN AS AN OUTLIER AT
THIS TIME. THE PATTERN SUGGESTS ABUNDANT RAIN OVER THE SOUTH, SOUTHEAST, AND
EAST COAST AREAS THANKS TO A STRONG INFLUX OF BOTH ATLANTIC AND GULF TROPICAL
MOISTURE. ALTHOUGH THIS FORECAST DOES NOT EXPLICITLY CONSIDER THE IMPACTS OF
ANY PARTICULAR TROPICAL WEATHER SYSTEM, IT SHOULD BE NOTED THAT THE CONSENSUS
OF LAST NIGHT'S CANADIAN ENSEMBLES SHOWED TROPICAL LOW PRESSURE APPROACHING
SOUTHEAST FLORIDA BY THE 19TH. THIS STORM WOULD COME FROM INTENSIFICATION OF
THE CURRENT AREA OF THUNDERSTORMS IN THE ATLANTIC EAST OF THE CARIBBEAN, WHILE
MODELS ALSO SUGGEST THE POSSIBILITY OF DEVELOPMENT FROM A DISTURBED AREA STILL
FARTHER EAST. IT IS TOO EARLY TO DISCUSS WHICH STORM WOULD MAKE LANDFALL AND
WHEN AND WHERE THIS WOULD HAPPEN, BUT THE TROPICAL ATLANTIC APPEARS TO BE
ENTERING AN ACTIVE STAGE.

http://www.hpc.ncep.noaa.gov/html/discuss.shtml


cieldumort
(Moderator)
Tue Aug 12 2008 04:44 AM
Re: Looking Around the Basin

A veritable cornucopia of possibilities exist for the wave/tropical low, 92L, and its brethren a little farther out behind it. Most of the mystery tonight has to do with how developed 92L already is, if it is, and to what extent the ULL to its north-northwest, and then the Bermuda High to follow, will play in its direction and development. With many possibilities, it's almost useless for much speculation until recon actually gets in there, flies the thing, tries to determine if a depression has already developed, or is about to, or is not nearly there at all, and what kind of environment it now finds itself in, now that it has seemingly veered way off course today.

Center reformation(s) and pull from the ULL have yanked the Invest well north of where it was expected to be by now. The Windwards may be close to an all-clear, but steering flow suggests that this northward jog may come to an end within the next 24-48 hours, with another sharp course correction to follow that could send it west, or even southwest.

At this time, based on satellite presentation only, it would be pretty easy for me to find an upgrade to TD possible (Tho a pretty lopsided TD, with convection all along the northern half, and virtually none south, but a depression, nonetheless). However, this assumes that a circulation is still tight and coherent at the surface, which is not at all clear at this time. Recon would help out with this tremendously.

There are reasons why we really need to know if 92L is or is not already a tropical cyclone well beyond the trivia. If a tropical cyclone has formed, or forms by the time recon is in there tomorrow, we might have a much better idea of how it is going to navigate the sidewindery steering currents ahead, and also if it is developed enough, and in enough of the right ways, as to have a better chance at fending off all the shear and dry air surrounding it and laying in wait.

Judging from total precipitable water content loops, 92L is already cocooned within a very symmetrical, spherical juice machine, and could surprise on the upside. But one wouldn't want to be the farm on it.

93L remains broad and elongated, but wrapped within a sub sandwich of deep-layered moisture and relatively low shear. As this system moves along to the west it might be the start of a turning point for more robust development should this elongation start to bunch up some more, allowing for real consolidation.


Storm Cooper
(User)
Tue Aug 12 2008 08:53 AM
Re: Discussion Excerpts

This relates to the post of danielw earlier and although all we have are Invests on the table right now and the following is model related...(Forecast Lounge)...attention is being paid to them and in turn will result in forecasting skill (if it plays out at all). A portion of the Tallahassee Area Forecast Discussion 4:06 AM EDT 8/12/08.....

ALSO THE 00Z EURO IS MORE BULLISH ON
TRACKING A POSSIBLE TROPICAL SYSTEM ACROSS CUBA MONDAY AND INTO
THE SOUTHEAST GULF TUESDAY. WITH THE AXIS OF THE SHARP UPPER
TROUGH TO OUR WEST...THIS WILL HAVE TO WATCHED CLOSELY.


JoshuaK
(Weather Guru)
Tue Aug 12 2008 11:43 AM
Attachment
Re: Discussion Excerpts

92L Looks much much better this morning, with a wave of convection firing up and wrapping around the circulation center. This thing definitly looks like a Tropical Depression to me, which I've added as of this posting time the latest visible satellite imagery -

http://flhurricane.com/cyclone/download.php?Number=81257


MikeCAdministrator
(Admin)
Tue Aug 12 2008 05:05 PM
Re: Discussion Excerpts

Recon is on it's way to check out 92L now, hopefully we'll learn more this afternoon from that. Right now it's still not likely to develop today.

WeatherNut
(Weather Master)
Tue Aug 12 2008 05:40 PM
Re: Discussion Excerpts

In the last couple of frames the convection on the NE end is starting to wrap up. The rotation is definitely more pronounced. Also the convection on the southwest side that seemed to be competing is fading. I think we'll have a TD when recon gets there.

NewWatcher
(Storm Tracker)
Tue Aug 12 2008 05:43 PM
Re: Discussion Excerpts

Recon is there, they have found west winds, it should be a TD. We will see.

Robert
(Weather Analyst)
Tue Aug 12 2008 06:04 PM
RE: Recon West winds

Do you have anything to back that up with? I cant found any recon reports with west winds at this time.
Wich website did you found that report at.


DrewC
(Verified CFHC User)
Tue Aug 12 2008 07:29 PM
Re: Discussion Excerpts

From looking at the satellite and water vapor loops, it appears that a clear center of rotation is forming today near 17N 52W (@ 3P EST), but the cloud tops have diminished quite a bit in the past couple hours. A question for the mets, is this just a diurnal fluctuation, or is it a product of the center becoming better defined? It does not appear to be from the dry air or shear.

Unregistered User
(Unregistered)
Tue Aug 12 2008 07:35 PM
Re: RE: Recon West winds


The naval research labs tropical cyclone page has posted a tropical cyclone formation alert for 92L.

http://www.nrlmry.navy.mil/tc_pages/tc_home.html

http://en.wikipedia.org/wiki/Tropical_Cyclone_Formation_Alert


Robert
(Weather Analyst)
Tue Aug 12 2008 08:50 PM
Re: Looking Around the Basin

Hmm im thinking shear? Already well it could be a stair step right now as it comes west it gets sheared, but when it goes north with it it flares up. i belive katrina and rita where such systems, that fought the shear and apeeared to loose but really just kept puslsating along north of the islands,andrew was symilar but does not count becuse he was alaways a tropical storm through the shear . I will have to sea with my eye's later tonight and tommorow morning what kinda system this wants to be.

LoisCane
(Veteran Storm Chaser)
Wed Aug 13 2008 01:47 AM
Re: Discussion Excerpts

circulation is very visible tonight and convection is flaring up dead center

http://www.ssd.noaa.gov/goes/flt/t1/loop-vis.html

i think its time to name the baby and get some good model forecasts before the baby grows up fast in the bahamas

think it's coming together


Hugh
(Senior Storm Chaser)
Wed Aug 13 2008 02:29 AM
Re: Discussion Excerpts

It's still pretty broad in terms of the convection, which isn't strong away from the "LLC" (if there is one).
Cloud tops appeared to peak about 2 hours ago, and are now declining a bit. I doubt that the NHC will upgrade it overnight based upon the current satellite and the recon info from today, but tomorrow's recon may very well find Fay if convection can build over the circulation.

Update: I just read where the next recon is scheduled to be in the system at 2am ET. If this is accurate, we may very well wake up to a named storm after all.


typhoon_tip
(Meteorologist)
Wed Aug 13 2008 02:30 AM
Re: Looking Around the Basin


The SE shear that had been impacting the broad circulation of 92L appears to have weakened considerably in the last 6 hours. The 10 to 15 kt shear vectors have reduce uniformly to around 5 kts.

There is a clear attempt at a "coring" of rotation, and there is even a small persistent cluster of deep convection near this perceived axis of rotation.

Some tropical models, such as the GFDL, are quite robust with intensity out in time. In fact, the 18z run ramps up 92L all the way to 121kts at 120 hours, in the Bahamas! This can't be an official call; however, I do not really see any big mitigators to development looking forward, as the TW (or depression) moves WNW.

As far as 93L goes, the water temperatures where this TW(s) is, are marginal actually... That combined with a touch of SAL contamination is probably why a clear and vigorous rotation is unable to find convection. It may just be a matter of time.


metwannabe
(Weather Hobbyist)
Wed Aug 13 2008 03:49 AM
Re: Looking Around the Basin

It seems odd to me that, even though shower and thunderstorm activity has diminished some with 92L, it otherwise certainly looks to have a clear circulation, it is trying to consolidate and gets its act together, that NHC has moved it from a high probability of development to a moderate probability.

I think if convection can continue to fire and sustains over the "center" we will have atleast a TD by morning if not a storm.


scottsvb
(Weather Master)
Wed Aug 13 2008 04:55 AM
Re: Looking Around the Basin

Chance for it being a TD by 5am is less than 10%, its fighting dry air and probably will take 24-48hrs and past 60W to be in any kind of enviroment to sustain convection.

MikeCAdministrator
(Admin)
Wed Aug 13 2008 12:08 PM
Re: Looking Around the Basin

Normally you look for a variety of factors looking to see if a depression has formed or not. In this case the wave east of the islands (92L) is still not matching enough for this, and probably won't today. Mostly the mention of it on the main page is a way to say hey there's something that could happen next week, so you may want to check over the weekend to see if it has developed or not. I do not want it to come anywhere near us, developed or not.

Recon, Dvorak numbers, satellite imagery and radar if you have it are some of the better ways to determine if it has formed or not (usually in that order). Recon hasn't found anything (and it's unusual recon goes this far east) the Dvorak numbers never reached around 2.0 and more are reasons it isn't a depression. And water vapor satellite along with visual are some of the better ways that I look for.

Right now with 92L, it doesn't look all that good. It just shows shearing and disorganized system at present, and it probably won't have a better shot at organization until if/when it gets north of the islands if it lasts that long.

Usually I"ll just read the NHC's data and look at the raw images/data myself before updating the main page, and before i read anyone else's take on the system too. Only after posting an update will I go check other opinions and then make notes on it after that.


craigm
(Storm Tracker)
Wed Aug 13 2008 12:14 PM
Re: Looking Around the Basin

92L looks terrible this morning in infra red although convection does appear to be making a come back in the north and west quadrants. Still has some SAL to fight through past 60W as posted above.

http://cimss.ssec.wisc.edu/tropic/real-time/wavetrak/winds/m8g10split.html

There is plenty of energy at the surface so it looks like we are in wait and see mode for a couple days.

http://www.ssd.noaa.gov/goes/flt/t1/loop-rgb.html


weathernet
(Storm Tracker)
Wed Aug 13 2008 12:43 PM
Re: Looking Around the Basin

As MIke pointed out this a.m., 92L remains just that - a dissorganized weak low. My own observation of visible and RGB satellite this morning seems to indicate a week surface circulation around 17N and 57W, but one not co-located with what appears to be a mid level rotation more to the east ( and north a bit ), around 18N & 54W. Water vapor indicates dry air on the systems west side.

Seems to be a distinct 20-30kt. southerly jet shearing the system. Whether this is part of a large broad closed ULL in the N.E. Carib., or simply a TUTT feature, 200mb charts do not indicate much change in the upper air until possibly 42 hours from now.

Some subtle model tendancies are becoming more evident, but will save such thoughts for the Forecast Lounge.


ftlaudbob
(Storm Chaser)
Wed Aug 13 2008 01:25 PM
Re: Looking Around the Basin

I keep thinking of 2005 when we had systems like 92l.They would flare up then die down flare up and die down,all the while moving west,then when they got closer to the mainland they would get their act together rather quickly.So we still need to watch 92l closely,because what ever may come of it is moving in our general direction.And it looks to me like if it can hang on for a couple more days,the conditions around this system should improve.

WeatherNut
(Weather Master)
Wed Aug 13 2008 01:55 PM
Re: Looking Around the Basin

I see a center forming at 17n 56w and there has been an impressive burst of convection in this area. Perhaps we are witnessing yet another center reformation. Lets see, however, if this burst fizzles like all the previous ones. This is very similar to all those storms in 2005 that were just about written off only to organize in a flash and then the bottom drops out. Big difference is this year there is not quite the anomalies in the ocean warmth dept.

ftlaudbob
(Storm Chaser)
Wed Aug 13 2008 02:06 PM
Re: Looking Around the Basin

Quote:

I see a center forming at 17n 56w and there has been an impressive burst of convection in this area. Perhaps we are witnessing yet another center reformation. Lets see, however, if this burst fizzles like all the previous ones. This is very similar to all those storms in 2005 that were just about written off only to organize in a flash and then the bottom drops out. Big difference is this year there is not quite the anomalies in the ocean warmth dept.




I would not say there is a BIG difference in the SSTs as compared to 2005.The SSTs get pretty warm as it moves west.This latest flare up should in the very least keep it alive for a while,but I still think we are a couple of days away from real organization.I am getting a little more concerned that this system is turning into a "fighter",I don't like those.


scottsvb
(Weather Master)
Wed Aug 13 2008 03:08 PM
Re: Looking Around the Basin

The elongated center of 92L is just NW of the T-Storm Convection....you can clearly see the shear over 92Ls position. If the center was a couple degrees east it would be in alot better shear zone/env. I put the position or (Trough)near 17-18N 58W as off 11am eastern.

The current flare up is due to daytime interaction with the upper low to its west. I would want to see convection at night and persistance and the LLC consolidate more. Dry Air is still inplace but eroding. Current threat right now is the shear axis of 15-20kts while it drops to under 10kts just a couple dg east of there.

(Edited to remove Forecast Lounge material.)


JoshuaK
(Weather Guru)
Wed Aug 13 2008 04:25 PM
Re: Looking Around the Basin

Looking on the latest visible and water vapour loops of 92L it appears that a big glob of convection has fired up over one of the circulation centers (which btw there appears to be multipule circulation points, one appearing within the heaviest portion of convection and another one on the SW edge of the convection).

scottsvb
(Weather Master)
Wed Aug 13 2008 05:19 PM
Re: Looking Around the Basin

So far on the 12z runs...,models are still showing at least a tropical storm by this weekend near 21N and 70W, some stronger but I would like to see the GFDL and HRW runs. Still we all need patience as right now its trying to form a ridge in the upper levels over it to support growth. The system will slowly get better organized as the dry air fades away and better the upper ridging over it strengthens over the next 12-24hrs. Until then, this will probably pulse with convection and we need persistance.

doug
(Weather Analyst)
Wed Aug 13 2008 07:39 PM
Re: Looking Around the Basin

Things were looking more bullish on 92L yesterday, I think. The shear over the system is hindering consistent convective activity, and all that is in the midst of the SAL surrounding it.
NHC is less optimistic than yesterday, when publishe reports put it at 50% for development and NRL posted the alert. Today it is 20-50%.
My concern is this will pulse late in the journey across and the relative weakness of the system will keep it from turning NW before the Bahamas, which will create a short track system that Florida must deal with.


LoisCane
(Veteran Storm Chaser)
Thu Aug 14 2008 12:51 AM
Re: Looking Around the Basin

It has a "rounder" look tonight again, convection flaring up strongly. One more strong bout with shear and then it has a better environment for development.

High is building in above it and the real piece of the puzzle as to what it does once it has a name is the strong frontal system pulling down from Canada this week/end. Over and over this summer we have storms come down on the same basic trajectory. Last night there were tornado warnings in Alabama, tonight Northern Florida. Jax had strong weather.. This is going to set up a scenario and a lot will depend on where and when this storm is and where that low is coming down towards Florida that shows what direction they race towards each other.

Timing is everything here. And, while it doesn't look like much tonight it will look better soon enough and we shouldn't be lulled into a false sense of security because this is calling for close in development much like Jeanne who didn't get her act together until she had moved into a closer in area vs mid-Atlantic.

The models are consistent and this storm has consistently followed the models.. something to remember while looking at a somewhat poor satellite presentation.

Across Florida, the Straits or paralleling the coast is too far away to predict.. it's at least 5 to 6 days away.

Puts the NHC under the gun to get good info on this storm. Imagine the Gulfstream Jet will go out as soon as they have a verified storm.


stormchazer
(Storm Tracker)
Thu Aug 14 2008 01:04 AM
Re: Looking Around the Basin

I think tonight is as good as 92L has looked in several days with inflow starting to develop. This seems to me to coincide with what early models had depicted. A weaker system developing as it moved closer in to the islands and the Bahamas.

If 92L does not die again tonight, it will get very interesting tomorrow.


Storm Hunter
(Veteran Storm Chaser)
Thu Aug 14 2008 01:08 AM
Re: Looking Around the Basin

I am curious what the NOAA plane may find tonight... most missions today and tonight were cancelled, but the "THE P3 RESEARCH MISSION FOR 14/06Z WILL GO AS SCHEDULED."

FLIGHT THREE -- NOAA 43
A. 14/0600Z
B. NOAA3 05DDA CYCLONE
C. 14/0300Z
D. 20.0N 58.0W
E. 14/0430Z TO 14/0930Z
F. SFC TO 14,000 FT

NOTE* the SFC to 14,000 FT... i think they be studying the dry air and dust in the surrounding enviroment of 92L which will be interesting to see what they find. Looks like take off is in a few hours. Will see what Ms. Piggy finds.

from today's POD...
2. OUTLOOK FOR SUCCEEDING DAY: CONTINUE 6-HRLY FIXES.
P-3 MISSIONS EVERY 12 HRS.

HRD is really wanting to get some data!!! That's good..

**NOAA 42 landed in Barbados around 18:49:00Z, yesterday the 12th**

(Edited to remove Forecast Lounge material.)


Storm Hunter
(Veteran Storm Chaser)
Thu Aug 14 2008 05:24 AM
Attachment
Re: Looking Around the Basin

see attached image to go with the following..

been watching NOAA3 fly and looking at IR shortwave... i thought the plane went through the old center ((i mean above)... the surface center thats about to enter the islands... which i think was around 17N 61W (which can be seen HERE )

but then about 30 mins ago.. recon was on the sw side of the convection and went across an area at 4,385 meters (~ 14,386 feet) at around 17.47N 59.48W and the winds changed almost 180 degrees and were less then 5mph at one point... almost like they flew through a small mid level low.. in the attached image.. its where the white bars are at. notice the wind shift?

and as i write, NOAA43 just went directly through that convection we see on sats... a BUMPY ride for sure!

the RED L is the 00Z location from models

**UPDATE... Flying through that blob.. pressure around 1009mb
Time: 05:06:30Z Coordinates:17.72N 58.85W
*SFMR Peak (10s) Sfc. Wind: 40 knots (~ 46.0 mph)
**Denotes suspect data***


flanewscameraman
(Weather Watcher)
Thu Aug 14 2008 06:10 AM
Re: Looking Around the Basin

It appears to the untrained eye that we are beginning to see the early formation of TD. All bets are off on where this may wind up in both intensity and direction at the moment, but it is interesting to see how the convection has persisted tonight. I believe the next few days will be interesting as we all watch how this plays out.

weathernet
(Storm Tracker)
Thu Aug 14 2008 06:18 AM
Re: Looking Around the Basin

Nice to be starting to get some data from recon; on practically every resolution early this morning, cannot help but be impressed by the maintaining CDO and improving outflow. Overall structure certainly giving the appearance of a more vertically stacked and possibly forming depression. Though sounds as if no such data has yet been offered up to corroborate by recon as of yet. Providing that the upper level shear is truly lessening, than may only be time before surface winds start working down to the surface. Would not be surprised if continued recon passes found a tight 1007mb pressure.

Robert
(Weather Analyst)
Thu Aug 14 2008 06:35 AM
Re: Watching Wave East of the Lesser Antilles

They already found 1007.8 out ahead of the system just to the west of convection with little winds switch from NE to SE. Its a 1009 under the convection


Time:
04:31:00Z
Coordinates:
17.88N 60.20W
Acft. Static Air Press:
594.4 mb (~ 17.55 inHg)
Acft. Geopotential Hgt:
4,524 meters (~ 14,843 feet)
Extrap. Sfc. Press:
1007.8 mb (~ 29.76 inHg)
D-value:
-
Flt. Lvl. Wind (30s):
From 49° at 13 knots (From the NE at ~ 14.9 mph)
Air Temp:
4.2°C (~ 39.6°F)
Dew Pt:
-2.2°C (~ 28.0°F)
Peak (10s) Flt. Lvl. Wind:
14 knots (~ 16.1 mph)
SFMR Peak (10s) Sfc. Wind:
9 knots (~ 10.3 mph)
SFMR Rain Rate:
0 mm/hr (~ 0 in/hr)
(*) Denotes suspect data



weathernet
(Storm Tracker)
Thu Aug 14 2008 07:00 AM
Re: Watching Wave East of the Lesser Antilles

Hmmm, sounds like not quite "co-located" surface to mid level, but given the continued bursting of convection, would anticipate perhaps yet an additonal couple millibar pressure fall. Perhaps "if and when" recon gets a 1005 / 1006mb pressure ( perhaps not on this mission ), than better indication of the systems improved vertical structure. At such a time, would anticipate surface winds to then perhaps substantiate upgrade to depression. Water vapor images are seemingly not depicting the same dry air, though still appears to have a lingering ULL impact by what appears as a TUTT feature to its east. Looks like upper levels improving as 92L progresses west to WNW. Other observation being BD curve showing nice cloud tops around -70 degrees in current convective burst.

cieldumort
(Moderator)
Thu Aug 14 2008 07:40 AM
Re: Watching Wave East of the Lesser Antilles

The current mission into 92L is certainly shedding a good bit of light on things. There are some hints that the low could be right smack in the process of closing back off at the surface overnight tonight. Obviously, should it be able to do so, especially while also blowing up all of this deep convection pretty much right on top of the location of lowest pressure, a tropical depression could be forming fortuitously right before the mission's eyes.

Unlike prior nights, 92L is now traveling through a much less hostile environment: The ULL to its west-northwest continues to scoot at a seemingly faster clip than 92 is, and may be weakening. An upper-level anticyclone sitting atop the disturbance looks to be setting up shop, and coming along for the ride. Dust in the vicinity is in far less supply, and without the previous levels of shear to shoot bullets of this killer SAL into the mix, the dust plague out ahead of it looks to be greatly diminished as an impediment to further development.

At this time, judging from the recon data just in, buoy and ship reports, it appears that 92L is still represented by a fairly robust mid-level low, with a now only slightly offset, broad surface low of around 1007-1008mb. Winds are coming up, which is also something we hadn't seen much of previously. It certainly looks like the Leeward Islands might very well be in for tropical depression-like conditions, whether or not it makes the cut by the time it (probably) crosses over (at least a portion of) them.



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