[NCEP Logo] HOME ARCHIVES FORECASTS IMAGERY ABOUT TPC RECONNAISSANCE

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TROPICAL STORM DEAN DISCUSSION NUMBER  10
NATIONAL WEATHER SERVICE MIAMI FL
5 AM AST TUE AUG 28 2001

DEAN HAS SHOWN A DECREASE IN CONVECTIVE ORGANIZATION OVER THE PAST
SEVERAL HOURS...WITH THE CENTER NOW DEFINED BY A SWIRL OF LOW/MID
LEVEL CLOUDS EAST OF THE PRIMARY CONVECTION.  SATELLITE INTENSITY
ESTIMATES FROM TAFB AND SAB ARE 55 KT...SO THAT IS THE INITIAL
INTENSITY FOR THIS ADVISORY.  ONE NEARBY SURFACE OBSERVATION IS FROM
CANADIAN BUOY 44141...WHICH AT 05Z REPORTED 1004.3 MB AND 18 FT SEAS
ABOUT 55 N MI SOUTHEAST OF THE CENTER.

DEAN HAS TURNED SHARPLY TO THE RIGHT OVER THE PAST 6 HR.  THE 12 HR
MOTION USED IN THE ADVISORY IS 045/20...AND THE SHORT-TERM MOTION IS
CLOSER TO 060/20.  DEAN IS NOW EMBEDDED IN THE WESTERLIES...AND
ALMOST ALL GUIDANCE AGREES ON A CONTINUED EAST-NORTHEAST OR
NORTHEAST MOTION FOR THE FORSEEABLE FUTURE.  THE ONE OUTLIER IS THE 
NHC 98...WHICH TURNS DEAN SHARPLY SOUTHEAST.  THE OFFICIAL FORECAST
WILL CALL FOR AN EAST-NORTHEAST TO NORTHEAST MOTION UNTIL DEAN
IS ABSORBED INTO AN EXTRATROPICAL LOW TO THE NORTHEAST OF
NEWFOUNDLAND BY 72 HR.  HOWEVER...IF THE CURRENT MOTION PERSISTS THE
TRACK WILL HAVE TO BE ADJUSTED SOUTHWARD.
 
DEAN IS ALREADY OVER 21C SEA SURFACE TEMPERATURES...AND EVEN AN
EASTWARD TURN WILL NOT BRING IT OVER ANY WARMER WATER.  THUS...
CONTINUED WEAKENING AND TRANSITION TO AN EXTRATROPICAL SYSTEM IS
EXPECTED.  THE MAIN EFFECT OF A MORE EASTERLY TRACK WOULD BE TO
REDUCE THE CHANCE OF DEAN GETTING ABSORBED BY THE LARGER LOW...
THUS PROLONGING ITS LIFE AS AN EXTRATROPICAL SYSTEM.
 
FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     28/0900Z 43.8N  54.9W    55 KTS
12HR VT     28/1800Z 45.4N  51.4W    50 KTS
24HR VT     29/0600Z 47.8N  46.6W    45 KTS...EXTRATROPICAL
36HR VT     29/1800Z 50.3N  41.8W    40 KTS...EXTRATROPICAL
48HR VT     30/0600Z 53.0N  37.0W    40 KTS...EXTRATROPICAL
72HR VT     31/0600Z...ABSORBED BY EXTRATROPICAL LOW
 
 
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