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| #44725 (Received by flhurricane at: 10:55 AM 08.Sep.2005) TCDAT1 TROPICAL STORM OPHELIA DISCUSSION NUMBER 9 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 AM EDT THU SEP 08 2005 SATELLITE IMAGERY DEPICTED ANOTHER BURST OF DEEP CONVECTION NEAR THE CENTER AND WSR-88D RADAR SHOWS THE MOST INTENSE REFLECTIVIES IN THE SOUTHERN PORTION OF A PARTIAL EYEWALL FEATURE...WITH DOPPLER VELOCITIES AROUND 65 KT AT 6000 FT. THE RADAR DATA AND SURFACE OBSERVATIONS ALSO INDICATE THAT SOME OF THE RAIN BANDS ARE SPREADING OVER PORTIONS OF THE COAST. A WIND GUST TO 41 KT WAS JUST MEASURED AT THE ST. AUGUSTINE C-MAN SITE. THERE IS WELL-DEVELOPED UPPER-LEVEL OUTFLOW TO THE WEST OF THE SYSTEM. OPHELIA IS OVER WARM WATERS AND VERTICAL SHEAR IS EXPECTED TO REMAIN IN THE 10-15 KT RANGE OVER THE NEXT FEW DAYS. SHIPS GUIDANCE DOES NOT SHOW THE SYSTEM BECOMING A HURRICANE UNTIL 48 HOURS. THE OFFICIAL FORECAST SHOWS SLOW STRENGTHENING...BUT THERE IS CERTAINLY A POSSIBILITY FOR THE CYCLONE COULD BECOME A HURRICANE SOONER THAN INDICATED. ANOTHER RECONNAISSANCE AIRCRAFT IS SCHEDULED TO INVESTIGATE THE STORM AROUND 18Z. STEERING CURRENTS REMAIN WEAK AND ILL-DEFINED...AND THERE HAS BEEN LITTLE OVERALL MOTION SINCE YESTERDAY. OPHELIA IS TRAPPED BETWEEN 2 SUBTROPICAL ANTICYCLONE CELLS. THERE ARE NO APPARENT SYNOPTIC- SCALE FEATURES TO BRING ABOUT SIGNIFICANT MOTION. HOWEVER THE GFS AND NOGAPS SUGGEST THAT SOME WESTERLY MOMENTUM WILL SINK SOUTHWARD NEAR OPHELIA AND PUSH THE SYSTEM A LITTLE EAST-NORTHEASTWARD OVER THE NEXT FEW DAYS. LATE IN THE PERIOD...HOWEVER...THE GLOBAL MODELS SHOW A MID-TROPOSPHERIC RIDGE BUILDING OVER THE UNITED STATES EAST COAST...WHICH WOULD EFFECTIVELY BLOCK FURTHER EASTWARD MOTION. MOST OF THE TRACK GUIDANCE SUGGESTS A NORTHEASTWARD TO EASTWARD MOTION WHICH SLOWS TO A CRAWL BY THE END OF THE PERIOD. THE GFDL HURRICANE MODEL IS THE OUTLIER AND LOOPS OPHELIA BACK TOWARD THE COAST BY 5 DAYS. THE OFFICIAL TRACK FORECAST IS A LITTLE EAST OF THE PREVIOUS ONE BUT NOT NEARLY AS FAR EAST AS THE BULK OF THE GUIDANCE. FORECASTER PASCH FORECAST POSITIONS AND MAX WINDS INITIAL 08/1500Z 28.6N 79.6W 50 KT 12HR VT 09/0000Z 28.7N 79.6W 55 KT 24HR VT 09/1200Z 29.0N 79.3W 60 KT 36HR VT 10/0000Z 29.5N 78.7W 65 KT 48HR VT 10/1200Z 30.0N 78.0W 65 KT 72HR VT 11/1200Z 31.0N 76.5W 65 KT 96HR VT 12/1200Z 31.0N 76.0W 70 KT 120HR VT 13/1200Z 30.5N 76.0W 70 KT |
