ATL: Ex Tropical Storm EARL - Discussion

[jimvb]

Interesting phenomenon. On the 2010 Aug 24 06Z GFS run at hour 48, Danielle, (probably) Earl, and an extratropical system that is right now off the New England coast form a near equilateral triangle in the middle of the Atlantic. This triangle has persisted for a few runs.

[blazess556]

SHOWERS AND THUNDERSTORMS CONTINUE TO BECOME BETTER ORGANIZED IN
ASSOCIATION WITH AN AREA OF LOW PRESSURE PASSING ABOUT 100 MILES
SOUTH OF THE CAPE VERDE ISLANDS...AND IT APPEARS THAT A TROPICAL
DEPRESSION COULD BE FORMING. IF THIS TREND CONTINUES... ADVISORIES
ON THIS SYSTEM COULD BE INITIATED AS EARLY AS LATER THIS MORNING.
THERE IS A HIGH CHANCE...90 PERCENT...OF THIS SYSTEM BECOMING A
TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES
WEST-NORTHWESTWARD AT NEAR 15 MPH. LOCALLY HEAVY SHOWERS AND
STRONG GUSTY WINDS ARE POSSIBLE OVER PORTIONS OF THE CAPE VERDE
ISLANDS TODAY...AND INTERESTS IN THOSE ISLANDS SHOULD MONITOR THE
PROGRESS OF THIS SYSTEM.

[GCANE]

Boundary-layer and mid-level moisture looks as good as where Danielle was in terms of location.

Yesterday it was a bit challanged, but MIMIC is showing a good developing convergence which will help protect from SAL.

A lot of overshooting tops are helping to warm the core and generate the so called 'pouch."

http://cimss.ssec.wisc.edu/tropic/real- ... t72hrs.gif

[KWT]

Looks like that area near the CV Islands is detached from the ITCZ convection to the south, i reckon this is a goer and probably becomes a storm down the line...

The only uncertainty in the longer term in terms of strength i shearing from Danielle but if I had to make a punt I'd say the chances are reasonable out to 4 days of a hurricane coming from this, I'd be doubtful of anything beyond that though to be honest.

[supercane]

12Z best track update from ATCF still shows it as a low, but I think the TWO suggests an upgrade:

AL, 96, 2010082412, , BEST, 0, 135N, 230W, 25, 1008, LO, 34, NEQ, 0, 0, 0, 0, 1011, 125, 40, 0, 0, L, 0, , 0, 0, INVEST, M,
AL, 96, 2010082406, , BEST, 0, 128N, 209W, 25, 1008, DB, 0, , 0, 0, 0, 0, 1009, 125, 40, 0, 0, L, 0, , 0, 0, INVEST, M,

[HURAKAN]

AL, 96, 2010082412, , BEST, 0, 135N, 230W, 25, 1008, LO

12z ... no upgrade

[supercane]

Latest microwave imagery shows solid convection around a possible center but very little banding:



Dvorak classifications from SSD increasing:
DATE/TIME LAT LON CLASSIFICATION STORM
24/1200 UTC 13.8N 23.0W T1.5/1.5 96L
24/0545 UTC 12.8N 20.9W T1.0/1.0 96L
23/2330 UTC 12.1N 19.1W TOO WEAK 96L

[supercane]

Latest ASCAT pass shows tighter circulation but having trouble resolving W winds:

[wxman57]

12Z best track update from ATCF still shows it as a low, but I think the TWO suggests an upgrade:

AL, 96, 2010082412, , BEST, 0, 135N, 230W, 25, 1008, LO, 34, NEQ, 0, 0, 0, 0, 1011, 125, 40, 0, 0, L, 0, , 0, 0, INVEST, M,
AL, 96, 2010082406, , BEST, 0, 128N, 209W, 25, 1008, DB, 0, , 0, 0, 0, 0, 1009, 125, 40, 0, 0, L, 0, , 0, 0, INVEST, M,

Question for one of you who knows more about these messages than I - what is that final letter in the line supposed to represent? They're both "M" here, but I see "S" and "D" on Danielle's file. They don't seem to correspond to any particular storm classification.

[KWT]

Very interesting supercane, that may well be why the NHC have held back on upgrading it then I suppose!

[senorpepr]

12Z best track update from ATCF still shows it as a low, but I think the TWO suggests an upgrade:

AL, 96, 2010082412, , BEST, 0, 135N, 230W, 25, 1008, LO, 34, NEQ, 0, 0, 0, 0, 1011, 125, 40, 0, 0, L, 0, , 0, 0, INVEST, M,
AL, 96, 2010082406, , BEST, 0, 128N, 209W, 25, 1008, DB, 0, , 0, 0, 0, 0, 1009, 125, 40, 0, 0, L, 0, , 0, 0, INVEST, M,

Question for one of you who knows more about these messages than I - what is that final letter in the line supposed to represent? They're both "M" here, but I see "S" and "D" on Danielle's file. They don't seem to correspond to any particular storm classification.

DEPTH - system depth, D-deep, M-medium, S-shallow, X-unknown

http://www.nrlmry.navy.mil/atcf_web/doc ... rdeck.html

[supercane]

Beat me to the punch, senorpepr

[ColinDelia]

Dvorak up to 1.5 from 1.0 six hours ago

DATE/TIME LAT LON CLASSIFICATION STORM
24/1200 UTC 13.8N 23.0W T1.5/1.5 96L

[cycloneye]

Aparently after the ASCAT pass, they decided to hold up on upgrading for now.

[HURAKAN]

latest

[KWT]

Aparently after the ASCAT pass, they decided to hold up on upgrading for now.

Yeah I think if I was in the NHC position I'd quite probably do the same thing as well to be honest!

[wxman57]

Just as with Danielle at first, there are two competing circulations. One north by the Cape Verde Islands, one well to the south. Until the two come together it'll be hard for 96L to organize. Will probably take another 12-24 hrs.

[Blown Away]

Just as with Danielle at first, there are two competing circulations. One north by the Cape Verde Islands, one well to the south. Until the two come together it'll be hard for 96L to organize. Will probably take another 12-24 hrs.

Wxman57 is 96L a likely fish/recurve? What's your take on the track and the probability it could make it far enough west to affect land?

[wxman57]

Just as with Danielle at first, there are two competing circulations. One north by the Cape Verde Islands, one well to the south. Until the two come together it'll be hard for 96L to organize. Will probably take another 12-24 hrs.

Wxman57 is 96L a likely fish/recurve? What's your take on the track and the probability it could make it far enough west to affect land?

Could take a track a little south of Danielle, but I don't see anything yet to indicate a definite Caribbean threat or a U.S. threat. We'll have to wait a few days to see how it comes together to be more confident.

[CrazyC83]

Is there dry air between Danielle and this? or if Danielle eats the dry air, could it allow this system to really take off?