000 WTNT42 KNHC 270232 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 7 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 PM AST THU AUG 26 2010 AFTER LOSING MOST OF ITS DEEP CONVECTION DURING THE AFTERNOON...EARL HAS DEVELOPED NEW THUNDERSTORM CELLS AROUND THE LARGE AND WELL-DEFINED CIRCULATION TONIGHT. T-NUMBERS HAVE NOT CHANGED AND STILL SUPPORT AN INITIAL INTENSITY OF 40 KNOTS. EARL IS MOVING TOWARD A WARMER OCEAN AND WILL LIKELY CONTINUE UNDER RELATIVELY LIGHT SHEAR FOR THE NEXT SEVERAL DAYS. GLOBAL MODELS INDICATE THAT EARL WILL DEVELOP A DEEP CIRCULATION SURROUNDED BY A LARGE UPPER-LEVEL OUTFLOW. THIS NORMALLY IS AN INDICATION OF STRENGTHENING AND IN FACT...BOTH THE HWRF AND GFDL MODELS DEVELOP EARL INTO AN INTENSE HURRICANE BY THE END OF THE FORECAST PERIOD. ON THIS BASIS...THE OFFICIAL FORECAST CALLS FOR EARL TO BECOME A HURRICANE IN A COUPLE OF DAYS WITH ADDITIONAL INTENSIFICATION THEREAFTER. ALTHOUGH THERE IS A LARGE CIRCULATION...THE CENTER IS DIFFICULT TO LOCATE. USING ENHANCED SATELLITE IMAGERY AND MICROWAVE DATA...THE BEST ESTIMATE OF THE INITIAL MOTION IS 280 DEGREES AT 15 KNOTS. EARL IS TRAPPED SOUTH OF A STRONG SUBTROPICAL RIDGE EXTENDING FROM AFRICA WESTWARD TO NEAR 60 DEGREES WEST. THIS PATTERN WILL KEEP THE CYCLONE ON A GENERAL WESTWARD TRACK FOR THE NEXT 3 DAYS OR SO. EARL SHOULD THEN BEGIN TO TURN MORE TO THE WEST-NORTHWEST AND NORTHWEST AS IT APPROACHES 60W WHERE THERE IS A PERSISTENT WEAKNESS IN THE SUBTROPICAL RIDGE. MOST OF THE TRACK MODELS ARE IN REMARKABLY GOOD AGREEMENT AND THE OFFICIAL FORECAST IS IN THE MIDDLE OF THE GUIDANCE ENVELOPE...BUT BIASED TO THE RELIABLE GFS AND ECMWF MODELS. FORECAST POSITIONS AND MAX WINDS INITIAL 27/0300Z 15.5N 40.2W 40 KT 12HR VT 27/1200Z 16.0N 42.8W 40 KT 24HR VT 28/0000Z 16.3N 46.0W 45 KT 36HR VT 28/1200Z 16.5N 49.3W 55 KT 48HR VT 29/0000Z 16.7N 52.5W 65 KT 72HR VT 30/0000Z 18.5N 58.0W 75 KT 96HR VT 31/0000Z 21.0N 62.0W 85 KT 120HR VT 01/0000Z 24.0N 65.0W 100 KT $$ FORECASTER AVILA