000 WTNT42 KNHC 301450 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 21 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 AM AST MON AUG 30 2010 THE EYE OF EARL HAS BECOME BETTER DEFINED IN VISIBLE SATELLITE IMAGERY THIS MORNING AND IS WELL-DEFINED IN RADAR IMAGERY FROM BOTH SAN JUAN AND ST. MAARTEN. AN AIR FORCE HURRICANE HUNTER AIRCRAFT MEASURED 700 MB FLIGHT-LEVEL WINDS OF 111 KT IN THE NORTHEAST EYEWALL AROUND 1200 UTC. THE AIRCRAFT HAS NOT SAMPLED THE NORTHEASTERN QUADRANT AGAIN...BUT FOUND 90 KT SFMR WINDS IN THE NORTHWEST EYEWALL AND A MINIMUM PRESSURE OF 960 MB. THIS SUPPORTS INCREASING THE INITIAL INTENSITY TO 105 KT...CATEGORY THREE ON THE SAFFIR-SIMPSON HURRICANE WIND SCALE. THE LOW SHEAR AND WARM WATER ENVIRONMENT AHEAD OF EARL APPEARS CONDUCIVE FOR ADDITIONAL STRENGTHENING DURING THE NEXT FEW DAYS. THIS SUPPORTS KEEPING EARL AT MAJOR HURRICANE STRENGTH DURING THAT TIME...ALTHOUGH EYEWALL CYCLES COULD INDUCE SOME FLUCTUATIONS IN INTENSITY. THE OFFICIAL FORECAST IS AT THE UPPER END OF THE INTENSITY GUIDANCE. LATE IN THE FORECAST PERIOD INCREASING SHEAR AND COOLER SSTS SHOULD INDUCE WEAKENING. THE INITIAL MOTION REMAINS 285/13. EARL IS EXPECTED TO TURN TOWARD THE NORTHWEST WITHIN THE NEXT DAY OR SO AS IT MOVES AROUND THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE DURING THE NEXT COUPLE OF DAYS. AFTER THAT TIME...EARL IS FORECAST TO TURN NORTHWARD...THEN NORTHEASTWARD AHEAD OF A MID-LATITUDE TROUGH THAT MOVES ACROSS THE GREAT LAKES AND INTO THE NORTHEAST UNITED STATES IN 4-5 DAYS. THE TRACK GUIDANCE HAS SHIFTED WESTWARD AGAIN AND THE OFFICIAL FORECAST HAS BEEN ADJUSTED IN THAT DIRECTION. THE UPDATED TRACK FORECAST IS NEAR THE MIDDLE OF THE TIGHTLY CLUSTERED GUIDANCE. 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 PORTION OF THE U.S. EAST COAST MIGHT SEE DIRECT IMPACTS FROM EARL. FORECAST POSITIONS AND MAX WINDS INITIAL 30/1500Z 18.7N 63.6W 105 KT 12HR VT 31/0000Z 19.5N 65.1W 115 KT 24HR VT 31/1200Z 21.0N 67.0W 125 KT 36HR VT 01/0000Z 22.8N 68.7W 125 KT 48HR VT 01/1200Z 25.2N 70.6W 120 KT 72HR VT 02/1200Z 31.0N 73.5W 110 KT 96HR VT 03/1200Z 37.5N 71.5W 100 KT 120HR VT 04/1200Z 45.5N 63.0W 75 KT...INLAND $$ FORECASTER BROWN/BERG