ATL: ERNESTO - Post-Tropical

[FireBird]

I thought that 99L would have consolidated all that associated convection ahead of it. Instead, there is now a clear separation, and a bit faster than I like. As a result, I am out of bed at 4am with a fantastic thunderstorm outside my window.
Any thoughts guys on what this might mean for 99L development? or is this a non-factor?

[GCANE]

Looks like starting to come together quickly now.

Cloud tops have really cooled just before sunrise and convection is firing off and well organized.

http://www.ssd.noaa.gov/PS/TROP/floater ... -long.html

Based on that and convergence seen on MIMIC-TPW, it is looking like its pulling north of 10N.

http://tropic.ssec.wisc.edu/real-time/m ... /main.html

Maintaining an excellent anti-cyclone

http://tropic.ssec.wisc.edu/real-time/w ... oom=&time=

UL outflow well supported by the ULL at 27N 44W

http://tropic.ssec.wisc.edu/real-time/w ... oom=&time=

Looks like UL Lows or trofs will be maintained thru 144 hrs NE of the Bahamas which should keep a poleward outflow channel intact.

http://moe.met.fsu.edu/cgi-bin/gfstc2.c ... =Animation

[GCANE]

So I looked a bit more closely at GFS and was wondering why it dissipates in the mid Carib.

Looking at 300mb vorticity, it appears an UL PV will interact with it when it gets south of PR and push down on it - spinning it down.

http://moe.met.fsu.edu/cgi-bin/gfstc2.c ... =Animation

The ULL will be key on how this progresses.

Something to keep an eye on in future model runs.

[abajan]

I thought that 99L would have consolidated all that associated convection ahead of it. Instead, there is now a clear separation, and a bit faster than I like. As a result, I am out of bed at 4am with a fantastic thunderstorm outside my window.
Any thoughts guys on what this might mean for 99L development? or is this a non-factor?

It's probably not a factor. Btw, Barbados had some pretty heavy thunderstorms yesterday afternoon.

[GCANE]

Strong overshooting tops NW of the LLC.

http://www.ssd.noaa.gov/PS/TROP/floater ... 0-lalo.jpg

http://rammb.cira.colostate.edu/product ... 010915.jpg

[Nimbus]

Personal Forecast Disclaimer:
The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.


The satellite presentation diminished over night but this morning we see a new burst, this is typical of a new system trying to develop in a somewhat dry environment. Aric said he thought there were telltale signs of a LLC on the northern fringe of convection yesterday. It will be easier to see the low altitude banded inflow this morning now that the convection is breaking away from the ITCZ. SST's are on the increase so they may still upgrade based on visual satellite presentation later today if the convection over the center persists.

The system looks like it is staying small and it may take a few more puffing convective bursts before it really starts to spin up. By then it will be past -50W and there is no way it will shoot off to the NE of the islands.

If 99L becomes a hurricane we can hope that an ULL circulation develops to the west of the storm and keeps the shear over it before it gets in the gulf. No guarantees in the upper atmosphere forecast though because its interactive with the storm, A major hurricane might build an anticyclone high over itself for example.

cycloneye adds Storm2k Disclaimer

[Gustywind]

Atlantic system getting better organized

Stu Ostro, Senior Meteorologist, The Weather Channel

Aug 1, 2012 5:25 am ET

http://www.weather.com/newscenter/hurri ... index.html

ATLANTIC

- The disturbance in the central tropical Atlantic yesterday was slow to consolidate, but today convection has been spinning more tightly around a center, thus increasingly exhibiting characteristics of a tropical cyclone. Before declaring a system to be one, typically the National Hurricane Center waits to ensure that such a trend toward organization is durable rather than transient. In any event, unlike was the case with the wave that is currently affecting Puerto Rico, the potential exists for further development of this one as it crosses the Atlantic. The timeline is for it to reach the Lesser Antilles by Friday or Friday night.

[Gustywind]

01/0545 UTC 9.4N 43.9W T1.0/1.0 99L
31/2345 UTC 9.2N 43.0W T1.0/1.0 99L

[Gustywind]

Loop
Looks like 99L is trying to detach from the ITCZ?

[Gustywind]

000
AXNT20 KNHC 010547
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT WED AUG 01 2012


...SPECIAL FEATURES...

A TROPICAL WAVE IS ANALYZED FROM 15N42W TO A 1012 MB LOW NEAR
10N43W WITH SHOWER/THUNDERSTORM ACTIVITY LOCATED ABOUT 955 NM
MILES E-SE OF THE WINDWARD ISLANDS HAS NOT BECOME ANY BETTER
ORGANIZED DURING THE PAST SEVERAL HOURS. ENVIRONMENTAL
CONDITIONS ARE MARGINALLY CONDUCIVE FOR GRADUAL DEVELOPMENT OF
THIS LOW OVER THE NEXT FEW DAYS. THIS SYSTEM HAS A MEDIUM CHANCE
OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT
MOVES W NEAR 15 KT. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION FROM 8N-12N BETWEEN 42W-47W.

[ronjon]

00z CMC now into north-central FL on its 240 hr run. Hmmm....

http://raleighwx.americanwx.com/models/ggem/00zggem500mbHGHTPMSLtropicalGGEMLoop.html

[Gustywind]

This discussion is by Rob of Crown Weather:

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org. For Official Information please refer to the NHC and NWS products.

http://www.crownweather.com/?page_id=4557


Invest 99L Continues To Become More Organized, Likely To Develop Into Tropical Storm Ernesto & Will Affect Barbados & The Lesser Antilles On Friday; Track & Intensity After That Remains In Question

Wednesday, August 1, 2012 5:42 am

by Rob Lightbown

Invest 99L, which is located a little over 1000 miles east-southeast of the Windward Islands has become better organized over the past 24 hours. Overnight and early morning satellite loops show deeper convection firing near the low pressure system. Additionally, this deeper convection has caused 99L to become better organized just in the last few hours. Also, environmental conditions appear to be favorable and remain favorable for this system to continue organizing and developing. I still think that Invest 99L will become a tropical depression as early as late today or early Thursday and then Tropical Storm Ernesto by late Thursday or early Friday.

The consensus track guidance as well as the latest NAM and GFS model guidance forecasts that 99L will remain on a slightly north of due west track over the next several days and pass very near or just south of Barbados during the day Friday and then across the Windward Islands towards later Friday. From there, the consensus track guidance and the GFS model (even though it really doesn’t develop it) keeps 99L on a track that takes it across the southern Caribbean this weekend.

The latest European model guidance has shifted significantly northward and forecasts 99L to track across the islands of Martinique and Dominica on Friday and then pass just south of Puerto Rico as a weakening system that opens up to a tropical wave by Saturday. The European model then forecasts 99L to track across the Bahamas from Sunday to Tuesday as a tropical disturbance. One item to point out in the European model guidance is that it forecasts another organizing tropical disturbance to begin approaching the Lesser Antilles during the weekend of August 11th and 12th.

So, here are my thoughts: I do think that it is likely that Invest 99L will become a tropical depression by late today or more likely during Thursday and then be upgraded from there to Tropical Storm Ernesto by Friday. As for a track, based on the track consensus guidance and the general motion of 99L, I think that a track either over or just north of Barbados seems quite possible during the day Friday as a 40 to 45 mph tropical storm. From there, I think we will see 99L track near the island of St. Lucia by late Friday as a 45 mph tropical storm. Now, it should be pointed out that this is an early “guess” based on all of the available data and this track idea can and likely will change.

Beyond the Lesser Antilles, I think that Invest 99L will track across the Caribbean and may not intensify at all due to less than favorable environmental conditions in the Caribbean.

All interests in the Lesser Antilles, especially those of you in Barbados and from the islands of Dominica southward to Grenada should be ready for tropical storm conditions on Friday with wind gusts to 50+ mph, heavy rainfall and rough seas. Do not wait for Invest 99L to be named to prepare for it.

I am monitoring Invest 99L closely and I will keep you all updated on the latest.

[Aric Dunn]

yes very interesting shift in the euro. likely because it has a strobger system early on compared to previous runs.

[ronjon]

Models looking increasingly like a FL peninsula to GOM threat for 99L.

http://www.sfwmd.gov/portal/page/portal/xweb%20weather/hurricane%20model%20plots

[TheBurn]

08:45z VIS / IR (Day / Night)

[NDG]

Satellite this morning shows that 99L is already feeling the effects of shear created by the large ULL to its north. The more latitude it gains the more that it will encounter.
I doubt that it will strengthen to more than a weak tropical storm.

[Blown Away]

06z GFS is interesting, still a westerly track into Caribbean but maintains the storm longer and is farther north and begins WNW movement in the Central Caribbean at @168 hours.
http://raleighwx.americanwx.com/models/ ... SLoop.html

[IreneSurvivor47]

Code red at 8am,

[AHS2011]

I just looked at a satellite this morning of invest 99l and I subconsciously said, "Wow, nice outflow." It is looking quite healthy on satellite. Also, does anyone have a link that shows the Dvorak Number on this system?

[Dean4Storms]

Looks like a TD now if you asked me.