000 WTNT43 KNHC 232035 TCDAT3 TROPICAL STORM SANDY DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL AL182012 500 PM EDT TUE OCT 23 2012 SATELLITE IMAGES CONTINUE TO SHOW FAIRLY WELL-DEFINED CONVECTIVE BANDING FEATURES...MAINLY OVER THE EASTERN PORTION OF THE CIRCULATION OF THE STORM. THE CENTER OF SANDY IS ESTIMATED TO BE LOCATED NEAR THE WESTERN EDGE OF A DEVELOPING CENTRAL DENSE OVERCAST FEATURE...WHICH IS INDICATIVE OF A BIT OF WESTERLY SHEAR OVER THE SYSTEM. HOWEVER...THE ATMOSPHERIC AND OCEANIC ENVIRONMENT IS EXPECTED TO FAVOR STRENGTHENING DURING THE NEXT DAY OR TWO WITH LAND INTERACTION BEING THE PRIMARY IMPEDIMENT. BY 72 HOURS... SOUTH-SOUTHWESTERLY SHEAR IS EXPECTED TO INCREASE TO MORE THAN 30 KT AND THIS SHOULD LIMIT STRENGTHENING. THE OFFICIAL INTENSITY FORECAST IS A BLEND OF THE LATEST STATISTICAL-DYNAMICAL SHIPS AND LGEM GUIDANCE. BY THE END OF THE PERIOD...GLOBAL MODEL FORECASTS SUGGEST THAT THE CYCLONE WILL BE DERIVING SOME ENERGY FROM BAROCLINIC SOURCES AND THE OFFICIAL FORECAST SHOWS POST-TROPICAL STATUS AT DAY 5. THE INITIAL MOTION IS ESTIMATED TO BE SLOWLY NORTH-NORTHEASTWARD... OR 020/5. NO SIGNIFICANT CHANGES HAVE BEEN MADE TO THE PREVIOUS TRACK FORECAST. AS A MID-TROPOSPHERIC RIDGE TO THE NORTH OF SANDY CONTINUES TO WEAKEN...THE TROPICAL CYCLONE SHOULD MOVE ON A NORTH-NORTHEASTWARD TO NORTHWARD HEADING WITH SOME INCREASE IN FORWARD SPEED OVER THE NEXT COUPLE OF DAYS. IN 2-3 DAYS...A SHARP UPPER-LEVEL TROUGH JUST TO WEST OF SANDY IS EXPECTED TO KEEP THE STORM ON A NORTHWARD TRACK...NEAR THE NORTHWEST BAHAMAS. LATER IN THE FORECAST PERIOD...INCREASING MID-LEVEL WESTERLY FLOW IS EXPECTED TO CAUSE A TURN TOWARD THE NORTHEAST. THE OFFICIAL FORECAST TRACK IS SIMILAR TO THE LATEST GFS AND ECMWF SOLUTIONS THROUGH 72 HOURS...AND CLOSE TO THE DYNAMICAL MODEL CONSENSUS. THE FORECAST TRACK AND EXPANDING WIND RADII SUGGEST THAT A TROPICAL STORM WATCH COULD BE REQUIRED FOR PORTIONS OF SOUTHEASTERN FLORIDA AND THE KEYS AS EARLY AS TONIGHT. FORECAST POSITIONS AND MAX WINDS INIT 23/2100Z 14.3N 77.6W 45 KT 50 MPH 12H 24/0600Z 15.7N 77.3W 55 KT 65 MPH 24H 24/1800Z 17.9N 77.1W 65 KT 75 MPH 36H 25/0600Z 20.3N 76.9W 70 KT 80 MPH...INLAND 48H 25/1800Z 22.8N 76.9W 60 KT 70 MPH...OVER WATER 72H 26/1800Z 26.3N 76.7W 60 KT 70 MPH 96H 27/1800Z 29.5N 73.5W 60 KT 70 MPH 120H 28/1800Z 32.0N 69.0W 60 KT 70 MPH...POST-TROPICAL $$ FORECASTER PASCH