000 WTNT43 KNHC 240245 TCDAT3 TROPICAL STORM SANDY DISCUSSION NUMBER 7 NWS NATIONAL HURRICANE CENTER MIAMI FL AL182012 1100 PM EDT TUE OCT 23 2012 REPORTS FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT SHOW THAT SANDY IS STRENGTHENING. THE AIRCRAFT REPORTED 850-MB FLIGHT-LEVEL WINDS OF 65 KT AND SFMR SURFACE WIND ESTIMATES NEAR 50 KT. THE MINIMUM CENTRAL PRESSURE WAS 989 MB. BASED ON THESE DATA...THE INITIAL INTENSITY IS RAISED TO 50 KT. THE AIRCRAFT ALSO REPORTED THAT A RAGGED EYE WAS FORMING. SANDY IS NOW MOVING FASTER WITH AN INITIAL MOTION OF 015/9. THE FORECAST SCENARIO AND THE FORECAST TRACK ARE BASICALLY UNCHANGED SINCE THE PREVIOUS ADVISORY. SANDY SHOULD MOVE GENERALLY NORTHWARD FOR THE NEXT 48 HR AS THE CYCLONE INTERACTS OR MERGES WITH AN MID/UPPER-LEVEL TROUGH TO ITS NORTHWEST AND A MID-LEVEL RIDGE TO THE NORTH OF THE CYCLONE WEAKENS. AFTER 72 HR...SOUTHWESTERLY MID/UPPER-LEVEL FLOW ASSOCIATED WITH A SECOND TROUGH OVER THE EASTERN UNITED STATES IS EXPECTED TO TURN THE CYCLONE NORTHEASTWARD. THE TRACK FORECAST IS IN GOOD AGREEMENT WITH THIS SCENARIO...WITH A TIGHT CLUSTERING OF THE GUIDANCE THROUGH 72 HR AND SOME SPREAD THEREAFTER. THE NEW FORECAST TRACK LIES NEAR THE CENTER OF THE GUIDANCE ENVELOPE...BETWEEN THE PREVIOUS FORECAST AND THE CONSENSUS MODELS. OVER THE CARIBBEAN...SANDY SHOULD CONTINUE TO INTENSIFY IN AN ENVIRONMENT OF LIGHT/MODERATE VERTICAL WIND SHEAR. THE INTENSITY FORECAST FOLLOWS THE PREVIOUS FORECAST IN MAKING SANDY A HURRICANE BEFORE THE CENTER REACHES JAMAICA AND CUBA. THE INTENSITY FORECAST BECOMES MUCH MORE COMPLEX AFTER THE CYCLONE EMERGES NORTH OF CUBA. WHILE ALL OF THE DYNAMICAL GUIDANCE SHOW STRONG SHEAR OVER SANDY...THEY ALL ALSO SHOW A SIGNIFICANT FALL IN THE CENTRAL PRESSURE AND AN INCREASE IN THE SIZE OF THE WIND FIELD. THIS APPEARS TO BE DUE TO BARCLINIC ENERGY FROM INTERACTION WITH THE MID/UPPER-LEVEL TROUGHS...AND IT IS LIKELY THAT SANDY WILL LOSE SOME OF ITS TROPICAL CHARACTERISTICS IN THE PROCESS. THAT BEING SAID...NONE OF THE GUIDANCE SHOWS THE CYCLONE ACTUALLY BECOMING EXTRATROPICAL DURING THE FORECAST PERIOD. THE NEW INTENSITY FORECAST WILL FOLLOW THE PREVIOUS FORECAST IN SHOWING A 60-KT INTENSITY AFTER 36 HR AND THE CYCLONE BECOMING POST-TROPICAL BY 120 HR. HOWEVER...THIS IS A LOW CONFIDENCE FORECAST FOR BOTH THE INTENSITY AND THE STRUCTURE OF THE CYCLONE. THE FORECAST TRACK AND EXPANDING WIND RADII SUGGEST THAT A TROPICAL STORM WATCH COULD BE REQUIRED FOR PORTIONS OF SOUTHEASTERN FLORIDA AND THE KEYS EARLY WEDNESDAY. FORECAST POSITIONS AND MAX WINDS INIT 24/0300Z 15.2N 77.2W 50 KT 60 MPH 12H 24/1200Z 16.7N 77.0W 60 KT 70 MPH 24H 25/0000Z 19.0N 76.7W 70 KT 80 MPH 36H 25/1200Z 21.7N 76.7W 60 KT 70 MPH 48H 26/0000Z 24.3N 76.8W 60 KT 70 MPH 72H 27/0000Z 27.0N 76.5W 60 KT 70 MPH 96H 28/0000Z 30.5N 72.5W 60 KT 70 MPH 120H 29/0000Z 33.0N 68.0W 60 KT 70 MPH...POST-TROPICAL $$ FORECASTER BEVEN