TS Josephine expected to strengthen

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