ATL: HELENE - Post-Tropical

[southerngale]

Again... PLEASE UPLOAD IMAGES BEFORE POSTING THEM.

If it's a new member doing it, that's one thing, but there's really no excuse for longtime members doing it repeatedly.

Everyone, please read this thread. Thank you.

http://www.storm2k.org/phpbb2/viewtopic.php?f=59&t=111268

[Weatherfreak000]

IMO, he comes in stronger. Dry air has been cleared out, and I don't think it has time to build back in, and Gordon takes advantage. Our first real chance at a major? We'll see, but with a stronger weakness setting up over the central GOM the Gulf Coast needs to be watching, and in general if your in the GOM at all, always keep one eye opened.
.

Possibly but I'm not overly impressed by that weakness, its shallow and doesn't dig that far down, not enough to scoop something that will likely be weak/very weak in the Caribbean. I'd personally only put its survival chances at something like 50-50 at the moment past 65W.

Okay, i'll bite KWT with what evidence do you suggest leads to that? I can personally at least cite the NHC's track as evidence. Seems kind of a trend here on Storm2k to make claims early on without any evidence, i'm curious what your seeing that lead you to that conclusion.

[KWT]

Okay, i'll bite KWT with what evidence do you suggest leads to that? I can personally at least cite the NHC's track as evidence. Seems kind of a trend here on Storm2k to make claims early on without any evidence, i'm curious what your seeing that lead you to that conclusion.

The NHC track suggests is survives and goes into the Caribbean, can't really deduct anything beyond that. fwiw given the NHC have even mentioned the possibility that this might weaken and open back to a wave, so thats some evidence there.

As for the track, I'm looking at the models and whilst I do see a weakness, its hardly pronounced. Its the type of weakness that will require a decently strong system to go into. I suspect by the time this one does get into much better conditions over W.Caribbean that weakness will be both too far east and already retreating out to make much difference. The fact we have a system that is heading westwards and from what I've heard from a met on another board, the models did a rather poor job forecasting the upper high with regards to Ernesto (though they did latch on in the end) leads to that conclusion.

I'm not that confident of it, don't get me wrong, though I do think it'll struggle in the E.Caribbean. Watch between 50-60W, think it'll flare up before it goes into the higher shear.

[HurricaneBelle]

Track wise this season is behaving like 2007.Dean and Felix due west thru the Caribbean

Based on one storm in early-mid August? I'm not adding TD 7 because it hasn't done anything yet.

2007 also featured a tropical storm hitting the west coast of FL in June like in 2012 (Barry then, Debby this year).

[Cyclenall]

I was semi-optimistic about this until I read this:

A STRONG MID-LEVEL RIDGE IS SITUATED TO THE NORTH OF THE DEPRESSION
AND THE CYCLONE IS MOVING RAPIDLY WESTWARD AT AROUND 17 KT. AN
EVEN FASTER FORWARD MOTION OVER THE NEXT SEVERAL DAYS IS INDICATED
BY THE GLOBAL MODELS...AND BY THE OFFICIAL FORECAST.

[JPmia]

so here's a question.. the 18z GFS also dissipates TD7 just south of hispainola.. is it shear or the land interaction dissipating it?

http://raleighwx.americanwx.com/models/18zgfs.html

[SouthDadeFish]

Nothing too impressive on microwave:

[cheezyWXguy]

Track wise this season is behaving like 2007.Dean and Felix due west thru the Caribbean

Based on one storm in early-mid August? I'm not adding TD 7 because it hasn't done anything yet.

2007 also featured a tropical storm hitting the west coast of FL in June like in 2012 (Barry then, Debby this year).

That doesn't make one season analogous to another. This season could then be claimed to be a lot like 2004 also because Bonnie took a similar track to both of those. Also, with the exception of the weak TS's earlier this year, the real active phase didnt take place this season until the beginning of August but I dont see anyone claiming a season parallel to that yet either. Theres a lot more going into it than just a track or two taking a similar direction. Its about the synoptic setup as a whole and how it evolves over time. Determining a season analog cannot be done with one or two storms just because they have similar tracks.

[Gustywind]

At 5PM, Meteo France placed Martinique in Tropical Storm "yellow watch", valid until Monday morning. Nothing for Guadeloupe.

IMHO, it's too early for a system more than 1700km far, they could have wait until tomorrow 10z, after 2 more advisories and 2 forecasts, but they are the Pro Mets, I'm not

Good point Ouragans . Off topic, in the same way concerning Guadeloupe ( even if they don't put a "yellow watch" for us), you have surely noted that (IMHO ) since the dramatic episode of January 2011 (6 death during the exceptionnal floodings), they don't take any risk and often overestimate the risk by putting an impressive number of yellow alert, lol. Back to TD 7, let's see how its evolves between 45W-60W...

[rainstorm]

for what its worth jb says forget about anything thru the 20th. he said that on bloomberg news. said td7 will fall apart. he does say he is warning his weatherbell clients the SE coast is at risk aug20th-sept5th. from what im not sure.

[wxman57]

I'm in favor of TD 7 falling apart in the Caribbean (or earlier). Time for a break after Ernesto. However, I suspect it'll linger either as a struggling TS or strong disturbance if it weakens in the Caribbean. Can't turn our back on it.

SAL does appear to still be an issue in advance of it:
http://tropic.ssec.wisc.edu/real-time/sal/splitE.jpg

[meriland23]

I was semi-optimistic about this until I read this:

A STRONG MID-LEVEL RIDGE IS SITUATED TO THE NORTH OF THE DEPRESSION
AND THE CYCLONE IS MOVING RAPIDLY WESTWARD AT AROUND 17 KT. AN
EVEN FASTER FORWARD MOTION OVER THE NEXT SEVERAL DAYS IS INDICATED
BY THE GLOBAL MODELS...AND BY THE OFFICIAL FORECAST.

forgive me for being a little inexperienced but.. what does this mean?

[tolakram]

I was semi-optimistic about this until I read this:

A STRONG MID-LEVEL RIDGE IS SITUATED TO THE NORTH OF THE DEPRESSION
AND THE CYCLONE IS MOVING RAPIDLY WESTWARD AT AROUND 17 KT. AN
EVEN FASTER FORWARD MOTION OVER THE NEXT SEVERAL DAYS IS INDICATED
BY THE GLOBAL MODELS...AND BY THE OFFICIAL FORECAST.

forgive me for being a little inexperienced but.. what does this mean?

The low levels are moving rapidly to the west at 17kts, which is fast, and are expected to move even faster. An LLC moving that fast will create something similar to a sheared system, but rather than the tops being blown off, the bottom is blown out from underneath the convection. Usually that's way too fast for a system to develop.

[meriland23]

Oh, well I was not sure if this helped development or hindered it

[HurricaneBelle]

That doesn't make one season analogous to another. This season could then be claimed to be a lot like 2004 also because Bonnie took a similar track to both of those. Also, with the exception of the weak TS's earlier this year, the real active phase didnt take place this season until the beginning of August but I dont see anyone claiming a season parallel to that yet either. Theres a lot more going into it than just a track or two taking a similar direction. Its about the synoptic setup as a whole and how it evolves over time. Determining a season analog cannot be done with one or two storms just because they have similar tracks.

Of course I could also point out how the "A" storms both formed in May off the SE Coast or how the "C" storms in both years both formed between Bermuda and the Bahamas and moved to the North Atlantic. But aside from all of that, I guess they're not similar at all.

[Nederlander]

Definitely not good for development. Low level coc will out run the mid level i.e. Ernesto's problem in the Caribbean.. I am just going to stick with the GFS on this system. It proved a lot of us wrong while we were stunned that Ernesto wasn't a major. A tilted stack is no bueno.

[Gustywind]

000
AXNT20 KNHC 100002
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU AUG 09 2012

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 2315 UTC.

...SPECIAL FEATURE...

TROPICAL DEPRESSION SEVEN FORMED AT 2100 UTC CENTERED NEAR 13.7N
43.8W...OR ABOUT 1005 NM E OF THE WINDWARD ISLANDS...MOVING W AT
17 KT. MINIMUM CENTRAL PRESSURE IS 1010 MB. MAXIMUM SUSTAINED
WIND SPEEDS ARE 30 KT WITH GUSTS TO 40 KT. PLEASE READ THE
LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT2/WTNT22 KNHC AND THE PUBLIC ADVISORY UNDER AWIPS/WMO
MIATCPAT2/WTNT32 KNHC FOR MORE DETAILS. A CLUSTER OF STRONG
CONVECTION IS W OF THE CENTER FROM 12N-14N BETWEEN 45W-48W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 13N-15N
BETWEEN 42W-45W.

[Gustywind]

09/2345 UTC 13.7N 44.3W T1.5/1.5 07L
09/1745 UTC 13.8N 42.9W T1.0/1.0 92L
http://www.ssd.noaa.gov/PS/TROP/tdpositions.html

[KWT]

Definitely not good for development. Low level coc will out run the mid level i.e. Ernesto's problem in the Caribbean.. I am just going to stick with the GFS on this system. It proved a lot of us wrong while we were stunned that Ernesto wasn't a major. A tilted stack is no bueno.

Not just that but I think the TUTT will probably shear this one as well, combine the LL speed, the possible shear and relative dry air that is expected in the E.Caribbean, and you've got cyclone killer conditions.

[ConvergenceZone]

I still think it will develop, at least into a mid strength tropical storm...
With the hardcore El Nino coming upon us, I think we will only make it up to storm H this year and that's about it....

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