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#371348 (Received by flhurricane at: 11:03 PM 25.Aug.2010) TCDAT1 HURRICANE DANIELLE DISCUSSION NUMBER 18 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062010 1100 PM AST WED AUG 25 2010 SATELLITE IMAGES INDICATE THAT DANIELLE HAS BECOME BETTER ORGANIZED DURING THE PAST SEVERAL HOURS. A LARGE CURVED BAND FEATURE EXTENDS AROUND THE HURRICANE...AND THE CENTRAL DENSE OVERCAST HAS BECOME MORE CIRCULAR WITH SIGNS OF A RAGGED EYE. MICROWAVE PASSES FROM 2000-2200 UTC CONFIRM THIS TREND AND SHOW THE DEVELOPMENT OF AN EYEWALL THAT IS MOSTLY CLOSED. THE INITIAL WIND SPEED IS RAISED TO 85 KT...AND IS A BLEND OF THE CI NUMBERS FROM TAFB/SAB. THE SIZE OF THE HURRICANE APPEARS TO BE EXPANDING ON SATELLITE...AND WIND ANALYSES FROM CSU/CIRA ALSO SHOW THIS GROWTH. BASED ON THE ABOVE DATA...THE INITIAL AND FORECAST WIND RADII HAVE BEEN INCREASED. IT IS A LITTLE SURPRISING THAT THE HURRICANE HAS BEEN INTENSIFYING AS WIND SHEAR ANALYSES FROM UW-CIMSS SHOW ABOUT 15 KT OF SOUTHWESTERLY SHEAR. THIS SHEAR IS FORECAST TO ABATE BY LATE TOMORROW AS AN UPPER-LEVEL LOW DROPS TO THE SOUTHWEST OF DANIELLE. THIS IS A COMMON SYNOPTIC SITUATION THAT SUPPORTS INTENSIFICATION AND NOW MOST OF THE GUIDANCE HAVE DANIELLE NEAR MAJOR HURRICANE STRENGTH ON FRIDAY. BY THE END OF THE PERIOD...THE HURRICANE SHOULD BE WEAKENING AS IT ENCOUNTERS COOLER WATER AND AN INCREASE IN SHEAR. THIS SCENARIO IS FOLLOWED IN THE OFFICIAL FORECAST...AND THE FORECAST INTENSITY IS A LITTLE HIGHER THAN THE PREVIOUS ONE. THE INITIAL MOTION IS ABOUT 320/15 DURING THE PAST 12 HOURS...AND EVEN A LITTLE TO THE RIGHT OF THAT RECENTLY. A LARGE TROUGH TO THE NORTH OF THE HURRICANE HAS APPARENTLY BEEN CAUSING IT TO MOVE A LITTLE TO THE RIGHT OF THE FORECAST PATH...BUT THE TROUGH IS RAPIDLY MOVING AWAY FROM DANIELLE. THIS SHOULD ALLOW A RIDGE TO REBUILD TO THE NORTH OF THE HURRICANE AND A LEFTWARD BEND OF THE TRACK BY TOMORROW NIGHT. IN A FEW DAYS...A TURN TO THE NORTH IS ANTICIPATED AS THE CYCLONE MOVES BETWEEN A RIDGE OVER THE CENTRAL ATLANTIC AND AN UPPER TROUGH OVER THE WESTERN ATLANTIC. GUIDANCE REMAINS DIVERGENT ON WHETHER THE HURRICANE WILL SIMPLY RECURVE OUT TO SEA WITH THAT TROUGH...OR WHETHER IT WILL BE LEFT BEHIND AND RESUME A SLOWER MOTION TO THE NORTHWEST OR NORTH. THE MOST RELIABLE MODELS ARE GENERALLY NEAR OR EAST OF THE MODEL CONSENSUS...AND THE OFFICIAL TRACK FORECAST WILL LEAN ON THAT SIDE OF THE GUIDANCE ENVELOPE...SLIGHTLY TO THE EAST OF THE PREVIOUS NHC TRACK. FORECAST POSITIONS AND MAX WINDS INITIAL 26/0300Z 22.4N 54.1W 85 KT 12HR VT 26/1200Z 23.7N 55.6W 90 KT 24HR VT 27/0000Z 25.0N 57.4W 95 KT 36HR VT 27/1200Z 26.1N 59.3W 100 KT 48HR VT 28/0000Z 27.5N 60.8W 100 KT 72HR VT 29/0000Z 30.3N 62.3W 100 KT 96HR VT 30/0000Z 33.5N 62.0W 90 KT 120HR VT 31/0000Z 37.0N 61.5W 80 KT $$ FORECASTER BLAKE |