416 
 WTNT44 KNHC 260245
 TCDAT4
 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