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#543038 (Received by flhurricane at: 4:38 PM 15.Sep.2012) TCDAT4 HURRICANE NADINE DISCUSSION NUMBER 18 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142012 500 PM AST SAT SEP 15 2012 NADINE HAS BEGUN TO LOOK A LITTLE MORE RAGGED THIS AFTERNOON. RECENT MICROWAVE DATA INDICATE THAT THE DEEP CONVECTION IS BEING SHEARED TO THE NORTHEAST OF THE LOW-LEVEL CENTER. DESPITE THE MORE DISHEVELED APPEARANCE...THE INTENSITY IS BEING HELD AT 70 KT BASED ON DVORAK CURRENT INTENSITY ESTIMATES OF 65 KT FROM TAFB AND 77 KT FROM SAB...AND A 70-KT ESTIMATE FROM THE UW-CIMSS ADT. NADINE HAS TURNED EASTWARD WITH AN INITIAL MOTION OF 090/14 KT. VISIBLE SATELLITE IMAGERY SHOWS LOW-LEVEL NORTHERLY FLOW IMPINGING ON THE NORTHERN SIDE OF NADINE...AND THE HURRICANE MAY RESPOND IN THE SHORT TERM BY MOVING A LITTLE SOUTH OF DUE EAST. HOWEVER...A GENERAL EASTWARD MOTION IS EXPECTED DURING THE NEXT 36 HOURS WHILE NADINE MOVES TOWARDS A COMPLEX AREA OF LOW PRESSURE NEAR THE AZORES. THIS COMPLEX LOW IS FORECAST TO BE REPLACED BY A MID-LEVEL ANTICYCLONE NORTH OF THE AZORES IN A FEW DAYS...WHILE ANOTHER LARGE DEEP-LAYER LOW DEVELOPS OVER THE CENTRAL ATLANTIC. THESE FEATURES WILL CAUSE NADINE TO MOVE NORTHEASTWARD ON DAYS 3 THROUGH 5 AND BECOME NEARLY STATIONARY NEAR THE AZORES. THE NHC TRACK FORECAST CONTINUES TO FOLLOW THE FASTER MODELS...PARTICULARLY THE GFS... ECMWF...AND THE FSU SUPERENSEMBLE...AND LITTLE CHANGE WAS REQUIRED TO THE PREVIOUS FORECAST. THE SHIPS DIAGNOSTICS SUGGEST THAT THE WESTERLY SHEAR AFFECTING NADINE COULD LIGHTEN UP A BIT OVER THE NEXT COUPLE OF DAYS...AND THE STATISTICAL GUIDANCE FLATLINES THE INTENSITY FOR ABOUT 48 HOURS. GRADUAL WEAKENING IS EXPECTED BY DAY 3 AS THE SHEAR CONTINUES AND NADINE MOVES OVER SEA SURFACE TEMPERATURES COLDER THAN 26C. THE NHC INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ONE AND JUST SHOWS A LITTLE MORE WEAKENING AT THE LATTER PART OF THE FORECAST PERIOD. FORECAST POSITIONS AND MAX WINDS INIT 15/2100Z 30.8N 48.2W 70 KT 80 MPH 12H 16/0600Z 30.7N 45.7W 70 KT 80 MPH 24H 16/1800Z 30.7N 41.9W 70 KT 80 MPH 36H 17/0600Z 31.3N 38.4W 70 KT 80 MPH 48H 17/1800Z 32.4N 35.7W 70 KT 80 MPH 72H 18/1800Z 35.0N 32.5W 65 KT 75 MPH 96H 19/1800Z 37.0N 31.5W 55 KT 65 MPH 120H 20/1800Z 38.0N 30.5W 50 KT 60 MPH $$ FORECASTER BERG |