000 WTNT41 KNHC 280245 TCDAT1 HURRICANE DANIELLE DISCUSSION NUMBER 27 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062010 1100 PM AST FRI AUG 27 2010 CONVENTIONAL AND MICROWAVE SATELLITE IMAGERY INDICATES THAT DANIELLE HAS STARTED AN EYEWALL REPLACEMENT CYCLE DURING THE PAST SEVERAL HOURS...WITH A 60 NM WIDE OUTER EYEWALL FORMING AROUND THE 15-20 NM WIDE INNER EYEWALL. THE INITIAL INTENSITY REMAINS 115 KT FOR THIS ADVISORY BASED ON SATELLITE ESTIMATES FROM TAFB AND SAB...BUT THIS COULD BE A LITTLE GENEROUS DUE TO THE EYEWALL REPLACEMENT. AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT IS ENROUTE TO INVESTIGATE DANIELLE. THE HURRICANE REMAINS IN A LIGHT VERTICAL SHEAR ENVIRONMENT WITH GOOD TO EXCELLENT CIRRUS OUTFLOW IN ALL DIRECTIONS. THE HURRICANE HAS TURNED TO THE RIGHT DURING THE PAST 6 HR WITH THE INITIAL MOTION NOW 335/8. THE TRACK GUIDANCE IS IN GOOD AGREEMENT THAT DANIELLE SHOULD TURN TOWARD THE NORTHEAST DURING THE NEXT 24 HOURS AND ACCELERATE INTO THE WESTERLIES THEREAFTER. THERE IS SOME SPREAD IN THE GUIDANCE ON THE SPEED OF MOTION DURING EXTRATROPICAL TRANSITION...WITH THE GFS AND CANADIAN MODELS SHOWING A FASTER MOTION THAN THE EUROPEAN AND THE UKMET. THE TRACK FORECAST SPLITS THE DIFFERENCE BETWEEN THOSE EXTREMES. IT IS UNLIKELY THAT DANIELLE WILL HAVE TIME TO COMPLETE THE EYEWALL REPLACEMENT CYCLE BEFORE IT ENCOUNTERS DECREASING SEA SURFACE TEMPERATURES AND INCREASING WIND SHEAR IN 24 HR OR SO. THE NEW INTENSITY FORECAST CALLS FOR A 115 KT INTENSITY FOR 12 HR...WITH STEADY WEAKENING THEREAFTER. EXTRATROPICAL TRANSITION SHOULD BEGIN AT ABOUT 96 HR AND BE COMPLETE BY 120 HR. THE DYNAMICAL MODELS FORECAST DANIELLE TO REMAIN A STRONG CYCLONE THROUGH TRANSITION... AND THIS IS REFLECTED IN THE INTENSITY FORECAST. FORECAST POSITIONS AND MAX WINDS INITIAL 28/0300Z 28.1N 60.6W 115 KT 12HR VT 28/1200Z 29.2N 60.7W 115 KT 24HR VT 29/0000Z 31.5N 59.4W 110 KT 36HR VT 29/1200Z 34.2N 57.1W 100 KT 48HR VT 30/0000Z 36.8N 53.9W 85 KT 72HR VT 31/0000Z 40.0N 46.5W 70 KT 96HR VT 01/0000Z 43.0N 37.5W 65 KT 120HR VT 02/0000Z 51.5N 28.5W 65 KT...POST-TROP/EXTRATROP $$ FORECASTER BEVEN