000 WTNT42 KNHC 312043 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 26 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 PM AST TUE AUG 31 2010 ALTHOUGH THE SATELLITE PRESENTATION IS NOT AS IMPRESSIVE AS IT WAS EARLIER...A RECONNAISSANCE PLANE AROUND 1700 UTC REPORTED A MINIMUM PRESSURE OF 940 MB AND MAXIMUM FLIGHT-LEVEL WINDS OF 128 KNOTS. THESE DATA SUPPORT AN INITIAL INTENSITY OF 115 KNOTS. CURRENTLY...THERE IS SOME SOUTHWESTERLY SHEAR DISRUPTING THE UPPER-LEVEL OUTFLOW OVER THE WESTERN SEMICIRCLE OF EARL. THIS SHEAR IS CAUSED BY A WEAK UPPER-LOW OR TROUGH OVER THE EASTERN BAHAMAS AS OBSERVED ON WATER VAPOR IMAGES. HOWEVER...MODELS WEAKEN THE UPPER LOW AS EARL MOVES AROUND IT...RESULTING IN A MORE FAVORABLE ENVIRONMENT. EARL IS EXPECTED TO MAINTAIN ITS CATEGORY FOUR INTENSITY FOR THE NEXT DAY OR TWO. EARL HAS BEGUN TO MOVE TOWARD THE NORTHWEST OR 305 DEGREES AT 12 OR 13 KNOTS DURING THE PAST FEW HOURS. THE SUBTROPICAL HIGH THAT IS STEERING EARL TOWARD THE WEST-NORTHWEST OR NORTHWEST IS FORECAST TO GRADUALLY SHIFT EASTWARD AS A BROAD TROUGH BECOMES ESTABLISHED OVER THE EASTERN UNITED STATES. THIS PATTERN WILL FORCE EARL ON A MORE NORTHWESTERLY AND NORTHERLY TRACK FOR THE NEXT DAY OR TWO. THEREAFTER...EARL WILL REACH THE BASE OF THE MID-LATITUDE WESTERLIES AND WILL LIKELY TURN SHARPLY TO THE NORTHEAST WITH AN INCREASE IN FORWARD SPEED. THIS IS THE SOLUTION UNANIMOUSLY PROVIDED BY TRACK GUIDANCE. ONCE AGAIN THE OFFICIAL FORECAST HAS BEEN SHIFTED A FEW MILES TO THE WEST BEFORE 48 HOURS FOLLOWING THE TRENDS OF THE ECMWF AND THE GFS. GIVEN THE LARGE AREA OF TROPICAL STORM FORCE WINDS ASSOCIATED WITH EARL...AND THE NEW DEFINITION OF WATCHES AND WARNINGS...A HURRICANE AND TROPICAL STORM WATCH HAS BEEN ISSUED FOR A PORTION OF THE MID- ATLANTIC COAST. INTERESTS FROM VIRGINIA NORTHWARD TO NEW ENGLAND SHOULD MONITOR THE PROGRESS OF EARL. FORECAST POSITIONS AND MAX WINDS INITIAL 31/2100Z 22.0N 68.8W 115 KT 12HR VT 01/0600Z 23.3N 70.5W 115 KT 24HR VT 01/1800Z 25.6N 72.8W 115 KT 36HR VT 02/0600Z 28.0N 74.5W 115 KT 48HR VT 02/1800Z 31.0N 75.5W 115 KT 72HR VT 03/1800Z 36.0N 73.5W 95 KT 96HR VT 04/1800Z 44.0N 65.0W 75 KT 120HR VT 05/1800Z 56.0N 55.0W 50 KT...POST-TROP/EXTRATROP $$ FORECASTER AVILA