Tropical Storm JOSEPHINE

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TROPICAL STORM JOSEPHINE DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL102008
500 PM EDT TUE SEP 02 2008

JOSEPHINE CONTINUES TO EXHIBIT A RATHER IMPRESSIVE APPEARANCE IN
VISIBLE IMAGERY...ALTHOUGH THE INFRARED CLOUD TOPS ARE STILL NOT
ALL THAT COLD...WITH SOLID AND FAIRLY SYMMETRIC CONVECTIVE BANDING
AND WELL-DEFINED UPPER-LEVEL OUTFLOW IN ALL DIRECTIONS.  LACKING
ACTUAL WIND DATA ANYWHERE NEAR THE CENTER OF THE CYCLONE...THE
INITIAL INTENSITY ESTIMATE IS AN UNCERTAIN 45 KT.  SOME DVORAK
ESTIMATES AND AN EARLIER AMSU INTENSITY ESTIMATE SUGGEST THE STORM
COULD BE A LITTLE STRONGER...BUT WE CAN WAIT UNTIL THE VARIOUS
ESTIMATES PERHAPS COME INTO BETTER AGREEMENT.  NEVER MIND THE
DETAILS...JOSEPHINE APPEARS POISED TO STRENGTHEN SOME MORE.  THE
STORM IS CURRENTLY LOCATED OVER RATHER WARM SEA-SURFACE
TEMPERATURES OF ABOUT 28 CELSIUS...AND THE WATERS WILL REMAIN THAT
WARM FOR ABOUT THE NEXT 24 HOURS.  COMBINE THAT WITH THE COMPLETE
ABSENCE OF WIND SHEAR...AND STRENGTHENING APPEARS LIKELY IN THE
SHORT TERM.  ALL OF THE OBJECTIVE GUIDANCE MODELS EXCEPT FOR THE
HWRF FORECAST A HURRICANE...AND THE INTENSITY CONSENSUS IS AT 65 KT
AT 24 HOURS.  THIS IS ALSO SHOWN IN THE NEW OFFICIAL FORECAST...
WHICH IS AN UPWARD ADJUSTMENT FROM THE PREVIOUS ADVISORY.  ALL OF
THE INTENSITY GUIDANCE CONTINUES TO FORECAST A WEAKENING TREND AT
DAYS 3-5...HOWEVER...IN RESPONSE TO JOSEPHINE PASSING OVER COOLER
SSTS IN A COUPLE OF DAYS...AND DUE TO INCREASING SOUTHERLY WIND
SHEAR ON THE EASTERN FLANK OF AN UPPER-LEVEL LOW.  GIVEN THIS
GUIDANCE...THE OFFICIAL FORECAST SHOWS A WEAKER CYCLONE AT FIVE
DAYS...AND EVEN 55 KT IS ABOVE NEARLY ALL OF THE MODEL PREDICTIONS.

A SUBTROPICAL RIDGE CENTERED NORTHWEST OF JOSEPHINE IS USHERING THE
TROPICAL CYCLONE WEST-NORTHWESTWARD AT ABOUT 290/12.  MODELS ARE
CLUSTERED FAIRLY TIGHTLY AROUND THIS SAME HEADING AND SPEED FOR THE
NEXT 48 HOURS.  AFTER THAT...THE GFDL AND HWRF FORECAST A FASTER
MOTION THAT EVENTUALLY BECOMES NORTHWESTWARD INTO A WEAKNESS IN THE
RIDGE ASSOCIATED WITH THE DEEP-LAYER LOW THAT WILL CROSS THE
NORTH-CENTRAL ATLANTIC.  THE GLOBAL MODELS ARE EITHER SLOWER OR
FARTHER SOUTH.  SINCE THE GFDL AND HWRF SEEM TO HAVE THE BEST
HANDLE ON THE INITIAL MOTION...THOSE SOLUTIONS ARE SLIGHTLY
FAVORED...AND THE OFFICIAL TRACK FORECAST IS A LITTLE RIGHT OF THE
CONSENSUS AND IS VERY SIMILAR TO THE PREVIOUS ADVISORY.
 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      02/2100Z 13.7N  25.9W    45 KT
 12HR VT     03/0600Z 14.2N  27.9W    60 KT
 24HR VT     03/1800Z 15.0N  30.5W    65 KT
 36HR VT     04/0600Z 15.9N  33.0W    70 KT
 48HR VT     04/1800Z 16.9N  35.5W    70 KT
 72HR VT     05/1800Z 19.0N  40.0W    60 KT
 96HR VT     06/1800Z 21.0N  44.0W    55 KT
120HR VT     07/1800Z 22.5N  48.5W    55 KT
 
$$
FORECASTER KNABB
 
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