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#372358 (Received by flhurricane at: 4:49 AM 30.Aug.2010) TCDAT2 HURRICANE EARL DISCUSSION NUMBER 20 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 AM AST MON AUG 30 2010 SINCE THE AIRCRAFT DEPARTED JUST PRIOR TO 0600 UTC...AN EYE HAS BEEN OCCASIONALLY APPARENT IN INFRARED IMAGERY...AND HAS BECOME BETTER DEFINED WITH A DIAMETER OF ABOUT 25 NM ON THE ST. MAARTEN RADAR. THE AIRCRAFT MEASURED A FLIGHT LEVEL MAXIMUM WIND OF 97 KT AT 0510 UTC...AND 0600 UTC DVORAK INTENSITY ESTIMATES WERE 90 KT FROM TAFB AND SAB. BASED ON THESE DATA...THE INITIAL INTENSITY IS SET TO 90 KT FOR THIS ADVISORY. THE OUTFLOW IS IMPROVING IN THE NORTHEASTERN QUADRANT AND IS GOOD ELSEWHERE...AND THE OVERALL ENVIRONMENT SHOULD SUPPORT STEADY INTENSIFICATION THROUGH THE NEXT 36 TO 48 HOURS. THE OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS ONE...AND SHOWS EARL REACHING MAJOR HURRICANE STATUS IN THE NEXT 12 TO 24 HOURS...FOLLOWED BY A BROAD PEAK IN INTENSITY BETWEEN 36 AND 72 HOURS. AFTER THAT TIME...EARL SHOULD BEGIN TO WEAKEN AS IT MOVES OVER COOLER WATERS AND ENCOUNTERS HIGHER VERTICAL WIND SHEAR. THE OFFICIAL FORECAST IS A BLEND OF THE SHIPS MODEL AND THE GFDL. BASED ON AIRCRAFT AND SATELLITE FIXES...THE INITIAL MOTION ESTIMATE REMAINS 285/13. EARL WILL GRADUALLY TURN TOWARD THE NORTHWEST IN THE NEXT DAY OR SO AS IT MOVES AROUND THE SOUTHWESTERN EDGE OF THE SUBTROPICAL RIDGE CENTERED ALONG 25N. THE TRACK MODEL GUIDANCE IS IN GOOD AGREEMENT ON THIS SCENARIO AND THE OFFICIAL FORECAST IS NEAR THE MIDDLE OF THE TIGHTLY CLUSTERED GUIDANCE ENVELOPE THROUGH 24 HOURS. AFTER THAT TIME MOST OF THE TRACK GUIDANCE HAS SHIFTED FARTHER WEST...ESPECIALLY AT 72 HOURS AND BEYOND...AS EARL TURNS NORTH-NORTHWESTWARD AND INTERACTS WITH A MID-LATITUDE TROUGH MOVING FROM THE GREAT LAKES INTO THE NORTHEASTERN U.S. GIVEN THE LARGE SHIFT IN THE MODELS...THE OFFICIAL FORECAST HAS BEEN ADJUSTED TO THE LEFT...OR WEST...BUT STILL LIES ON THE EASTERN EDGE OF THE GUIDANCE SUITE. THIS IS A GOOD TIME TO REMIND EVERYONE THAT NHC AVERAGE TRACK FORECAST ERRORS ARE 200 TO 300 MILES AT DAYS 4 AND 5. GIVEN THIS UNCERTAINTY...IT IS TOO SOON TO DETERMINE WHAT...IF ANY...PARTS OF THE U.S. EAST COAST MIGHT SEE DIRECT IMPACTS FROM EARL LATER THIS WEEK. FORECAST POSITIONS AND MAX WINDS INITIAL 30/0900Z 18.3N 62.4W 90 KT 12HR VT 30/1800Z 19.1N 64.0W 95 KT 24HR VT 31/0600Z 20.3N 66.0W 105 KT 36HR VT 31/1800Z 21.9N 67.8W 115 KT 48HR VT 01/0600Z 24.0N 69.6W 115 KT 72HR VT 02/0600Z 29.5N 73.0W 115 KT 96HR VT 03/0600Z 35.5N 72.5W 100 KT 120HR VT 04/0600Z 42.0N 65.5W 85 KT $$ FORECASTER BRENNAN |