000 WTNT45 KNHC 050244 TCDAT5 TROPICAL STORM JOSEPHINE DISCUSSION NUMBER 12 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL102008 1100 PM EDT THU SEP 04 2008 JOSEPHINE HAS BEEN MOVING IN A STAIR STEPPED FASHION DURING THE LAST SEVERAL HOURS BUT A 12 HR AVERAGE YIELDS 290/09. THIS GENERAL MOTION IS FORECAST TO CONTINUE FOR THE NEXT DAY OR SO AS THE CYCLONE IS STEERED BY A LARGE SUBTROPICAL RIDGE TO THE NORTH. AFTER THAT...A WEAKNESS IS FORECAST TO DEVELOP IN THE RIDGE...WHICH SHOULD ALLOW A TURN TOWARD THE NORTHWEST. THERE IS STILL SOME SPREAD IN THE TRACK GUIDANCE WITH THE NOGAPS...GFDL...AND HWRF MODELS FORECASTING A MORE POLEWARD TRACK WHILE THE UKMET... GFS...MODELS KEEP JOSEPHINE MOVING WEST-NORTHWEST. SINCE TRACK GUIDANCE HAS BEEN TRENDING NORTHWARD...THE NEW OFFICIAL FORECAST IS SHIFTED A LITTLE TO THE NORTH BUT STILL LIES ALONG THE SOUTHERN SIDE OF THE GUIDANCE ENVELOPE. JOSEPHINE IS CURRENTLY EXPERIENCING SOUTHERLY VERTICAL SHEAR ASSOCIATED WITH A LARGE UPPER-LEVEL LOW TO ITS WEST WHICH IS INHIBITING DEVELOPMENT. WITH THE SHEAR EXPECTED TO REMAIN STRONG FOR ANOTHER COUPLE OF DAYS AND THE SSTS FALL ALONG THE FORECAST TRACK... SIGNIFICANT DEVELOPMENT IS NOT EXPECTED. HOWEVER...IF JOSEPHINE CAN SURVIVE THE NEXT COUPLE OF DAYS...THE ENVIRONMENT COULD BECOME MORE FAVORABLE FOR STRENGTHENING. IN FACT...SOME OF THE GLOBAL MODELS DEVELOP AN UPPER-LEVEL ANTICYCLONE OVER JOSEPHINE AND THE SSTS RISE ALONG THE FORECAST. STILL...NONE OF THE AVAILABLE GUIDANCE FORECAST SIGNIFICANT STRENGTHENING AND THE GFDL AND HWRF MODELS ACTUALLY SHOW THE CYCLONE ESSENTIALLY DISSIPATING. THE OFFICIAL FORECAST ASSUMES JOSEPHINE WILL SURVIVE LONG ENOUGH TO REACH THE MORE FAVORABLE ENVIRONMENT AND SHOWS A LITTLE RESTRENGTHENING AT DAYS 3-5. FORECAST POSITIONS AND MAX WINDS INITIAL 05/0300Z 15.1N 33.8W 40 KT 12HR VT 05/1200Z 15.4N 34.9W 40 KT 24HR VT 06/0000Z 15.8N 36.3W 35 KT 36HR VT 06/1200Z 16.5N 37.9W 35 KT 48HR VT 07/0000Z 17.5N 39.8W 35 KT 72HR VT 08/0000Z 19.5N 44.0W 40 KT 96HR VT 09/0000Z 21.5N 48.0W 40 KT 120HR VT 10/0000Z 23.5N 51.0W 45 KT $$ FORECASTER RHOME