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| #5561 (Received by flhurricane at: 4:50 AM 18.Aug.2004) TCDAT4 HURRICANE DANIELLE DISCUSSION NUMBER 20 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 AM EDT WED AUG 18 2004 DANIELLE IS EXPERIENCING SOME MODERATE SOUTHWESTERLY UPPER-LEVEL SHEAR. A COMBINATION OF THE SHEAR AND SOME DRY AIR ALSO PUNCHING IN FROM THE SOUTHWEST HAS RESULTED IN THE LOW-LEVEL CIRCULATION BECOMING PARTLY EXPOSED NEAR THE SOUTHWESTERN EDGE OF THE CONVECTIVE CLOUD SHIELD. HOWEVER...THE CIRCULATION IS STILL JUST INSIDE THE CONVECTIVE CLOUD SHIELD...SO DANIELLE IS BEING MAINTAINED AS A 65-KT HURRICANE. THE INITIAL INTENSITY OF 65 KT IS CONSISTENT WITH A BLEND OF DVORAK T-NUMBERS OF T3.5...OR 55 KT... AND CURRENT INTENSITY NUMBERS OF T4.5...OR 77 KT. THE INITIAL MOTION IS 360/12. EVEN THOUGH DANIELLE HAS BECOME PARTLY SHEARED...THE LOW-LEVEL CIRCULATION HAS BEEN KEEPING UP WITH THE CONVECTIVE CLOUD SHIELD. THIS IS A TESTAMENT TO THE DEEP VERTICAL CIRCULATION THAT THIS CYCLONE HAD WHEN IT CAME OFF WEST AFRICA ALMOST A WEEK AGO. SINCE DANIELLE WILL REMAIN OVER 26C AND HIGHER SSTS FOR THE NEXT 48 HOURS OR SO...INTERMITTENT CONVECTION SHOULD CONTINUE TO BURST NEAR THE CENTER AND HELP TO KEEP THE VERTICAL CIRCULATION INTACT. THIS SHOULD ALLOW THE CYCLONE TO GRADUALLY ROUND THE TOP OF THE RIDGE LOCATED ALONG 30-32N LATITUDE...AND THEN TURN NORTHEASTWARD AND ACCELERATE AFTER THAT AS THE A MID- TO UPPER-LEVEL TROUGH GRADUALLY CAPTURES IT. THE FORECAST TRACK IS SIMILAR TO THE PREVIOUS FORECAST AND IS CLOSE TO THE GUNS CONSENSUS MODEL...SINCE THE GUNA CONSENSUS IS MUCH SLOWER AS A RESULT OF THE GFS MODELING RAPIDLY WEAKENING DANIELLE AND KEEPING IT STATIONARY. EVEN THOUGH DANIELLE HAS WEAKENED SIGNIFICANTLY IN THE PAST 6 HOURS...THE OCEAN IS EXPECTED TO REMAIN WARM ENOUGH TO SUPPORT CONTINUED CONVECTIVE DEVELOPMENT FOR ABOUT THE NEXT 48 HOURS. AFTER THAT...DANIELLE IS FORECAST TO BECOME ABSORBED BY AN APPROACHING FRONTAL SYSTEM FROM THE NORTHWEST AND BE A GALE AREA AS IT MOVES THROUGH THE AZORES ISLANDS. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 18/0900Z 27.9N 40.7W 65 KT 12HR VT 18/1800Z 29.4N 40.5W 60 KT 24HR VT 19/0600Z 31.3N 39.5W 55 KT 36HR VT 19/1800Z 32.7N 38.4W 50 KT 48HR VT 20/0600Z 33.8N 37.0W 50 KT 72HR VT 21/0600Z 36.5N 32.5W 45 KT...BECOMING EXTRATROPICAL 96HR VT 22/0600Z 40.0N 26.0W 40 KT...EXTRATROPICAL 120HR VT 23/0600Z 46.0N 16.0W 35 KT...EXTRATROPICAL |
