000 WTNT44 KNHC 010239 TCDAT4 HURRICANE NADINE DISCUSSION NUMBER 74 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142012 1100 PM AST SUN SEP 30 2012 NADINE HAS CONTINUED TO SLOWLY WEAKEN DURING THE PAST SEVERAL HOURS. THE EYE OF THE HURRICANE HAS BECOME INCREASINGLY MORE RAGGED...AND CLOUD TOP TEMPERATURES HAVE GENERALLY BEEN WARMING. THERE HAS ALSO BEEN AN EROSION OF DEEP CONVECTION THROUGHOUT THE CIRCULATION... WITH THE BULK OF WHAT REMAINS PIVOTING FROM WEST TO SOUTH AROUND THE CENTER. DVORAK T-NUMBERS ARE GRADUALLY DECREASING...AND A BLEND OF T- AND CI-NUMBERS GIVES AN INITIAL INTENSITY ESTIMATE OF 75 KT. A SLOW BUT STEADY DECAY OF THE CYCLONE IS EXPECTED DURING THE NEXT 12-24 HOURS AS NADINE ENCOUNTERS GRADUALLY INCREASING SHEAR AND THE COLD WAKE THAT THE CYCLONE GENERATED YESTERDAY. FROM 24-72 HOURS... A MARKED INCREASE IN NORTHWESTERLY TO NORTHERLY SHEAR AND EVEN COOLER WATERS COULD HASTEN THE WEAKENING TREND. PROHIBITIVELY HIGH SHEAR AFTER 72 HOURS MIGHT RESULT IN A DECOUPLING OF THE STORM... AND NADINE IS NOW FORECAST TO BECOME A REMNANT LOW SOONER...IN 96 HOURS. THE NHC INTENSITY FORECAST IS ADJUSTED DOWNWARD COMPARED TO THE PREVIOUS ONE...AND IS IN BEST AGREEMENT WITH THE FLORIDA STATE SUPERENSEMBLE OUTPUT. NADINE HAS CONTINUED TO SLOW DOWN WHILE IN THE PROCESS OF MAKING A CYCLONIC LOOP...AND THE SHORT-TERM INITIAL MOTION ESTIMATE IS 230/06. THE NORTHEASTWARD EXTENSION OF A MID-LEVEL RIDGE OVER THE WEST-CENTRAL ATLANTIC SHOULD CAUSE HEIGHTS TO RISE NORTH OF NADINE DURING THE NEXT 24 HOURS. THIS PATTERN COULD RESULT IN NADINE SLOWING FURTHER AS IT HEADS BACK SOUTHWARD AND THEN SOUTH- EASTWARD. AFTER 48 HOURS...THE WEAKENING STORM SHOULD TURN EASTWARD AND NORTHEASTWARD AS IT ACCELERATES AHEAD OF A DEEP-LAYER CYCLONE MOVING OUT OF ATLANTIC CANADA. THE TRACK GUIDANCE HAS SHIFTED TOWARD THE SOUTH AND EAST SINCE THE LAST CYCLE...WITH THE GFS/ECMWF SOLUTIONS ON THE RIGHT SIDE OF THE GUIDANCE ENVELOPE. THE NHC TRACK FORECAST FOLLOWS THE TREND IN THE GUIDANCE TOWARD THE RIGHT...BUT IS NOT AS FAR SOUTH AND EAST AS THE MULTI-MODEL CONSENSUS. FORECAST POSITIONS AND MAX WINDS INIT 01/0300Z 36.7N 39.4W 75 KT 85 MPH 12H 01/1200Z 36.3N 39.5W 65 KT 75 MPH 24H 02/0000Z 35.7N 39.0W 60 KT 70 MPH 36H 02/1200Z 35.2N 37.9W 55 KT 65 MPH 48H 03/0000Z 35.4N 36.4W 50 KT 60 MPH 72H 04/0000Z 38.0N 31.3W 45 KT 50 MPH 96H 05/0000Z 44.6N 26.4W 40 KT 45 MPH...POST-TROPICAL 120H 06/0000Z 50.0N 27.3W 40 KT 45 MPH...POST-TROP/EXTRATROP $$ FORECASTER KIMBERLAIN