Tropical Storm DEBBY

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TROPICAL STORM DEBBY DISCUSSION NUMBER  18
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL042006
1100 PM EDT FRI AUG 25 2006
 
DESPITE CURRENT INTENSITY NUMBERS FROM TAFB AND SAB WHICH SUPPORT
DOWNGRADING DEBBY TO A DEPRESSION...A QUIKSCAT PASS FROM EARLIER
THIS AFTERNOON INDICATED THAT TROPICAL STORM FORCE WINDS ARE STILL
POSSIBLE IN A SMALL AREA ABOUT 90 NM NORTHEAST OF THE CENTER. 
SATELLITE IMAGERY AND QUIKSCAT DATA ALSO INDICATE THAT WHILE THERE
IS A DEFINITE LOW-LEVEL CENTER...THE SYSTEM IS BECOMING
INCREASINGLY ELONGATED AND ASYMMETRIC.  AN UPPER LEVEL LOW IS
EXPECTED TO MAINTAIN SOUTHERLY SHEAR OVER DEBBY FOR THE NEXT 2 TO 3
DAYS...SO IT IS UNLIKELY THAT THE CYCLONE...IN ITS CURRENT FRAGILE
STATE...WOULD BE ABLE TO SURVIVE THE FRONTAL SYSTEM WHICH WILL BE
APPROACHING FROM THE NORTHWEST.  CYCLONE PHASE DIAGRAMS AND MODEL
FIELDS SUGGEST THAT DEBBY SHOULD BEGIN EXTRATROPICAL TRANSITION IN
36 HOURS THEN BECOME FULLY ABSORBED IN THE FRONTAL ZONE BY 72
HOURS.  THE OFFICIAL INTENSITY FORECAST CLOSELY FOLLOWS THE SHIPS
AND FSU SUPERENSEMBLE GUIDANCE IN MAINTAINING A MARGINAL TROPICAL
STORM.  HOWEVER...IT COULD WEAKEN TO A DEPRESSION AT ANY TIME.

DEBBY HAS TAKEN A SLIGHT WESTWARD JOG WITH AN INITIAL MOTION OF
300/12.  THE SYSTEM WILL BEGIN TO RECURVE TO THE NORTH IN THE NEXT
24 TO 48 HOURS IN RESPONSE TO AN APPROACHING UPPER TROUGH AND ITS
ASSOCIATED COLD FRONT.  DEBBY WILL THEN ACCELERATE NORTHEASTWARD
BEYOND 48 HOURS AS IT BECOMES ABSORBED INTO THE FRONTAL ZONE.  THE
OFFICIAL TRACK FORECAST IS ONLY SLIGHTLY LEFT OF THE PREVIOUS
FORECAST AND VERY CLOSE TO THE MODEL CONSENSUS.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      26/0300Z 25.2N  45.6W    35 KT
 12HR VT     26/1200Z 26.5N  47.1W    35 KT
 24HR VT     27/0000Z 28.5N  48.5W    35 KT
 36HR VT     27/1200Z 30.8N  48.7W    40 KT...BECOMING EXTRATROPICAL
 48HR VT     28/0000Z 33.6N  47.5W    50 KT...EXTRATROPICAL
 72HR VT     29/0000Z...ABSORBED BY A FRONT
 
$$
FORECASTER BERG/KNABB
 
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