000 WTNT41 KNHC 272043 TCDAT1 HURRICANE DANIELLE DISCUSSION NUMBER 26 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062010 500 PM AST FRI AUG 27 2010 THE CONVECTIVE CLOUD STRUCTURE OF DANIELLE HAS IMPROVED A LITTLE DURING THE DAY AND THE 15-20 NMI DIAMETER EYE REMAINS VERY DISTINCT. UPPER-LEVEL OUTFLOW IS GOOD IN ALL QUADRANTS AND CONTINUES TO IMPROVE TO THE NORTH AND EAST OF THE HURRICANE. AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT INVESTIGATED DANIELLE EARLIER THIS AFTERNOON AND FOUND A CENTRAL PRESSURE OF 942 MB AND MAXIMUM 700 MB FLIGHT-LEVEL WINDS OF 119 KT...WHICH EQUATES TO ABOUT 107 KT SURFACE WINDS. MAXIMUM SFMR WINDS WERE ONLY 101 KT...HOWEVER. SATELLITE INTENSITY ESTIMATES FROM SAB AND TAFB WERE A CONSENSUS T6.0/115 KT. UW-CIMSS ADT ESTIMATES ARE T6.4/125 KT... AND HAVE BEEN INCREASING OVER THE PAST COUPLE OF HOURS. A BLEND OF THESE INTENSITY ESTIMATES SUPPORTS KEEPING THE INTENSITY AT 115 KT FOR THIS ADVISORY. THE INITIAL MOTION ESTIMATE IS 310/08. THE NHC MODEL GUIDANCE REMAINS TIGHTLY PACKED THROUGH 48-72 HOURS...AND IS STILL INDICATING SHARP RECURVATURE BY 24 HOURS AROUND THE SUBTROPICAL RIDGE THAT LIES ALONG 29N-30N LATITUDE. AFTER RECURVATURE OCCURS...A STRONG MID-LEVEL TROUGH CURRENTLY PUSHING SOUTHEASTWARD OFF THE EASTERN U.S. COAST AND CANADIAN MARITIMES REGION IS FORECAST TO ACCELERATE DANIELLE QUICKLY TO THE NORTHEAST OR EAST-NORTHEAST AND GRADUALLY CAPTURE THE CYCLONE AT HIGHER LATITUDES BY 96 HOURS...AND THEN TURN IT SHARPLY POLEWARD BY 120 HOURS AS A STRONG AND DEEP EXTRATROPICAL CYCLONE. THE OFFICIAL FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY TRACK THROUGH 96 HOURS...AND THEN A MORE POLEWARD AT DAY 5...WHICH REMAINS CONSISTENT WITH THE CONSENSUS MODELS...TVCN AND TVCC. DANIELLE MAY STRENGTHEN SLIGHTLY DURING THE NEXT 12-24 HOURS AS THE HURRICANE MOVES INTO A REGION OF LOWER VERTICAL SHEAR AND OVER 29C SSTS. BY 36 HOURS...HOWEVER...INCREASING SOUTHWESTERLY VERTICAL SHEAR AHEAD OF THE AFOREMENTIONED TROUGH SHOULD COMBINE WITH DECREASING SSTS TO INITIATE STEADY WEAKENING. AROUND 96 HOURS OR SO...DANIELLE SHOULD BEGIN EXTRATROPICAL TRANSITION AS IT MERGES WITH A STRONG FRONTAL SYSTEM AND BE FULLY EXTRATROPICAL BY 120 HOURS AS A VERY LARGE 60-KT LOW PRESSURE SYSTEM OVER THE FAR NORTH ATLANTIC. THE OFFICIAL INTENSITY FORECAST IS A BLEND OF THE VARIOUS INTENSITY MODELS. ALTHOUGH THE CENTER OF DANIELLE IS EXPECTED TO PASS WELL TO THE EAST OF BERMUDA...THE LARGE AND EXPANDING WIND FIELD ON THE WEST SIDE OF THE HURRICANE COULD BRING TROPICAL-STORM-FORCE WINDS CLOSE TO BERMUDA ON SATURDAY. FOR THIS REASON...A TROPICAL STORM WATCH HAS BEEN ISSUED FOR THAT ISLAND. FORECAST POSITIONS AND MAX WINDS INITIAL 27/2100Z 27.3N 60.3W 115 KT 12HR VT 28/0600Z 28.6N 61.0W 120 KT 24HR VT 28/1800Z 30.5N 60.8W 110 KT 36HR VT 29/0600Z 32.8N 59.0W 100 KT 48HR VT 29/1800Z 35.1N 56.3W 85 KT 72HR VT 30/1800Z 38.4N 49.7W 75 KT 96HR VT 31/1800Z 41.8N 39.1W 65 KT 120HR VT 01/1800Z 50.0N 28.0W 60 KT...POST-TROP/EXTRATROP $$ FORECASTER STEWART