|
Show Selection: |
| #213529 (Received by flhurricane at: 10:38 AM 04.Sep.2008) TCDAT5 TROPICAL STORM JOSEPHINE DISCUSSION NUMBER 10 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL102008 1100 AM EDT THU SEP 04 2008 A QUIKSCAT OVERPASS AT 0754 UTC SHOWED A RELIABLE-LOOKING 50 KT WIND. HOWEVER...THE DEEP CONVECTION THAT WAS PRESENT AT THAT TIME HAS DISSIPATED...LEAVING AN EXPOSED LOW-LEVEL CENTER WELL TO THE SOUTHWEST OF SMALL AREAS OF DISORGANIZED CONVECTION. BASED ON THIS...IT IS ESTIMATED THAT JOSEPHINE HAS WEAKENED TO 45 KT. THE INITIAL MOTION REMAINS 285/9. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS ADVISORY. JOSEPHINE IS FORECAST TO MOVE IN A GENERAL WEST-NORTHWESTWARD MOTION ALONG THE SOUTHERN PERIPHERY OF LARGE SUBTROPICAL RIDGE FOR THE NEXT 36-48 HOURS. AFTER THAT...A WEAKNESS IS FORECAST TO DEVELOP IN THE RIDGE...WHICH SHOULD ALLOW JOSEPHINE TO MAKE A NORTHWARD JOG AT 72-96 HR...BEFORE THE RIDGE FILLS BACK IN FORCING THE CYCLONE ON A LITTLE MORE WESTWARD BY 120 HOURS. THE GUIDANCE DOES SHOW SOME SPREAD IN THE FORWARD SPEED...WITH THE UKMET BEING THE SLOWEST...THE GFDL AND HWRF BEING THE FASTEST...AND THE OTHER MODELS IN BETWEEN. THE NEW FORECAST TRACK COMPROMISES IN SPEED BETWEEN THE GFDL/HWRF AND THE MODEL CONSENSUS...BUT IS SLOWER THAN THE PREVIOUS ADVISORY. THE TRACK CONTINUES ALONG THE SOUTHERN EDGE OF THE GUIDANCE ENVELOPE. JOSEPHINE CONTINUES TO EXPERIENCE 20-25 KT OF SOUTHWESTERLY VERTICAL WIND SHEAR DUE TO THE LARGE UPPER-LEVEL TROUGH TO ITS NORTHWEST. THE SHEAR IS FORECAST TO CONTINUE FOR 36-48 HR WHILE JOSEPHINE MOVES OVER SLIGHTLY COOLER SEA SURFACE TEMPERATURES. ON THIS BASIS... THE NEW INTENSITY FORECAST CALLS FOR A LITTLE MORE WEAKENING...THEN MAINTAINS A 40 KT INTENSITY THROUGH 72 HR. SOME FLUCTUATIONS IN STRENGTH COULD OCCUR DURING THIS TIME DUE TO CONVECTIVE BURSTS. AFTER 72 HR...THE SHEAR MAY DECREASE...ALTHOUGH THE LARGE-SCALE MODELS DO NOT AGREE ON THIS. ON THE BASIS THAT THE SHEAR DECREASES AS JOSEPHINE REACHES WARMER WATERS...THE FORECAST CALLS FOR SLIGHT INTENSIFICATION. THE INTENSITY FORECAST IS IN BEST AGREEMENT WITH THE SHIPS MODEL... ALTHOUGH IT IS ABOVE ALL THE INTENSITY GUIDANCE EXCEPT SHIFOR. FORECAST POSITIONS AND MAX WINDS INITIAL 04/1500Z 14.5N 32.2W 45 KT 12HR VT 05/0000Z 14.9N 33.5W 40 KT 24HR VT 05/1200Z 15.3N 35.2W 40 KT 36HR VT 06/0000Z 15.8N 36.7W 40 KT 48HR VT 06/1200Z 16.4N 38.3W 40 KT 72HR VT 07/1200Z 18.0N 42.0W 40 KT 96HR VT 08/1200Z 20.0N 46.0W 45 KT 120HR VT 09/1200Z 21.5N 50.0W 50 KT $$ FORECASTER BEVEN |
