|
Show Selection: |
| #45495 (Received by flhurricane at: 10:43 AM 12.Sep.2005) TCDAT1 TROPICAL STORM OPHELIA DISCUSSION NUMBER 25 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 AM EDT MON SEP 12 2005 LATEST DATA FROM THE AIR FORCE RECONNAISSANCE INDICATED A PEAK 700 MB FLIGHT LEVEL WIND OF 63 KT. MAXIMUM SURFACE WINDS ARE ESTIMATED TO BE NEAR 60 KT...ALTHOUGH THIS IS PROBABLY GENEROUS GIVEN THE LACK OF DEEP CONVECTION TO TRANSPORT MOMENTUM VERTICALLY. THUS THE SYSTEM IS BEING DOWNGRADED TO A TROPICAL STORM ON THIS ADVISORY. OPHELIA HAS NOT MOVED MUCH OVER THE LAST COUPLE OF DAYS...SO UPWELLING AND STIRRING HAS LIKELY COOLED THE WATERS. SHIP AND DRIFTING BUOY DATA SUGGEST THAT THE SEA SURFACE TEMPERATURES MAY HAVE DECREASED TO BELOW 26 DEG C BENEATH THE STORM CENTER. THE TRACK FORECAST TAKES OPHELIA OVER A SECTION OF THE GULF STREAM... WHERE A MODESTLY DEEP WARM WATER MIXED LAYER...I.E. HIGHER OCEANIC HEAT CONTENT...COULD INDUCE RE-STRENGTHENING. THEREFORE THE OFFICIAL FORECAST SHOWS THE SYSTEM RE-ATTAINING HURRICANE STRENGTH BEFORE NEARING THE COAST. AFTER COMPLETING A SMALL CLOCKWISE LOOP...THE STORM IS MOVING VERY SLOWLY NORTHWESTWARD...315/02. BECAUSE THE STEERING CURRENTS ARE SO ILL-DEFINED...THE TRACK FORECAST REMAINS A DIFFICULT ONE. SOME GLOBAL MODELS...NAMELY NOGAPS AND THE CANADIAN...INDICATE THAT THE BROAD 500 MB TROUGH APPROACHING THE EASTERN UNITED STATES IN A COUPLE OF DAYS WILL LACK SUFFICIENT AMPLITUDE TO PICK UP OPHELIA AND ACCELERATE IT NORTHEASTWARD. THEREFORE WE HAVE THE UNPLEASANT POSSIBILITY THAT THE CYCLONE COULD LINGER NEAR THE SOUTHEAST U.S. THROUGH 5 DAYS. THE GFS AND GFDL STILL MOVE OPHELIA NORTHEASTWARD OVER THE ATLANTIC BEYOND 3 DAYS...BUT THEY ARE SOMEWHAT SLOWER THAN THEIR PREVIOUS RUNS. IN DEFERENCE TO THIS NUMERICAL GUIDANCE...THE OFFICIAL FORECAST IS A BIT SLOWER THAN THE PREVIOUS ONE IN THE 3-5 DAY TIME FRAME. FORECASTER PASCH FORECAST POSITIONS AND MAX WINDS INITIAL 12/1500Z 31.6N 76.8W 60 KT 12HR VT 13/0000Z 31.8N 77.4W 60 KT 24HR VT 13/1200Z 32.3N 77.7W 65 KT 36HR VT 14/0000Z 33.0N 77.7W 65 KT 48HR VT 14/1200Z 33.9N 77.4W 70 KT 72HR VT 15/1200Z 35.5N 76.0W 65 KT 96HR VT 16/1200Z 38.0N 73.0W 55 KT 120HR VT 17/1200Z 41.0N 68.0W 45 KT...EXTRATROPICAL |
