ATL: HELENE - Post-Tropical

[wxman57]

I was a bit surprised at the NHC's more westerly track (diverging from consensus) yesterday afternoon (and current). I think the more westerly track is more likely. The consensus models appear to be more to the north because of the inclusion of the UKMET and NOGAPS models which take the depression across the extreme NE Caribbean then off to the NW. These two models are almost certainly wrong, given the strong ridge building north of the depression.

And in the longer range, the Euro an GFS build a ridge westward across Florida and the Gulf, all the way to Mexico. They were quite right with the pattern in advance of Ernesto, and I think they're right again. This would suggest a continued westerly movement toward either the southern Yucatan or Nicaragua/Honduras.

Next question is intensity. Indications are that the depression will be fighting the same battle with shear and dry air as Ernesto, perhaps even more so. It could well dissipate or open up to a wave after entering the Caribbean.

[Aric Dunn]

Looking at this morning... its possible its already starting to open back up. I needs more persistent convection.

[Gustywind]

Slight decreasing numbers...
10/1145 UTC 13.7N 47.8W T1.0/1.5 07L
10/0545 UTC 13.7N 46.2W T1.5/1.5 07L

[Gustywind]

Loop
http://sirocco.accuweather.com/sat_mosa ... aeatle.gif

[Blown Away]

12z models, TVCN modest shift north.

[wxman57]

Consensus models shifted north because both the NOGAPS (worthless model) and UKMET take 7 north of the Caribbean toward the eastern Bahamas. That's unlikely, given the projected ridge (by GFS/Euro) building to its north. That ridge is forecast to extend form the Bahamas to Texas by next Wednesday. Throw those two models out and you have a track very much like Ernesto, except that this system may not survive the shear and dry air.

[sphelps8681]

Wxman57 your thoughts above regarding movement of this system is exactly what are local met here said last night. That we would be under high pressure throughout the entire gulf and likely movement would be toward the west.

[tolakram]

LLC exposed.



live loop: http://wwwghcc.msfc.nasa.gov/cgi-bin/ge ... umframes=7

[tolakram]

saved loop

[OuterBanker]

Shear, dry air and it does look as if it will get close to the DR/Haiti shreding machine too.
Afraid Gordon to be is on a death march.

[Blown Away]

06z dynamic model runs, all well north of the NHC line. Interested to see if the NHC shifts north at 11am or disregards the 06z models?

[wxman57]

Just measured 1 and 3-hr movement and got 27-28 kts (28kts last hour).

[Cyclenall]

Just measured 1 and 3-hr movement and got 27-28 kts (28kts last hour).

RIH (opposite of RIP) TD7 . Even watching that loop made me dizzy it was moving so fast!

[Gustywind]

000
WTNT32 KNHC 101452
TCPAT2

BULLETIN
TROPICAL DEPRESSION SEVEN ADVISORY NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL AL072012
1100 AM AST FRI AUG 10 2012

...TROPICAL DEPRESSION MOVING FASTER TO THE WEST...INTERESTS IN THE
WINDWARD AND LEEWARD ISLANDS SHOULD MONITOR THE PROGRESS THIS
SYSTEM...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...13.7N 49.5W
ABOUT 775 MI...1245 KM E OF THE WINDWARD ISLANDS
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...W OR 270 DEGREES AT 23 MPH...37 KM/H
MINIMUM CENTRAL PRESSURE...1009 MB...29.80 INCHES


WATCHES AND WARNINGS
--------------------
INTERESTS IN THE WINDWARD AND LEEWARD ISLANDS SHOULD MONITOR THE
PROGRESS OF THE DEPRESSION SINCE TROPICAL STORM WATCHES OR WARNINGS
COULD BE REQUIRED AT ANY TIME.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 1100 AM AST...1500 UTC...THE CENTER OF TROPICAL DEPRESSION SEVEN
WAS LOCATED NEAR LATITUDE 13.7 NORTH...LONGITUDE 49.5 WEST. THE
DEPRESSION IS MOVING TOWARD THE WEST NEAR 23 MPH...37 KM/H...AND
THIS GENERAL MOTION IS LIKELY TO CONTINUE FOR THE NEXT COUPLE OF
DAYS. ON THE FORECAST TRACK...THE DEPRESSION WILL APPROACH THE
WINDWARD AND LEEWARD ISLANDS SATURDAY NIGHT.

MAXIMUM SUSTAINED WINDS REMAIN NEAR 35 MPH...55 KM/H...WITH HIGHER
GUSTS. SOME STRENGTHENING IS POSSIBLE DURING THE NEXT 48
HOURS...AND THE DEPRESSION COULD BECOME A TROPICAL STORM BEFORE
REACHING THE LESSER ANTILLES.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 1009 MB...29.80 INCHES.


HAZARDS AFFECTING LAND
----------------------
NONE


NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...500 PM AST.

$$
FORECASTER BERG

[wxman57]

I don't think it'll survive to become a TS. Bones is getting a bit antsy.

[psyclone]

Wow it looks really bad this morning. i think the possibility of dissipation is significant.

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[Aric Dunn]

its trying to make a come back... some convection firing.

[wxman57]

its trying to make a come back... some convection firing.

"Do or do not, there is no try!" That convection is south of what looks like a weakening LLC. Oh, and I just measured the last hour's movement at 270 deg and 36 kts.

[Aric Dunn]

its trying to make a come back... some convection firing.

"Do or do not, there is no try!" That convection is south of what looks like a weakening LLC. Oh, and I just measured the last hour's movement at 270 deg and 36 kts.

Yeah I agree is meager at best.

[greenkat]

Random Question: is flooding an issue with small island countries like Barbados or Saint Lucia? Just curious