000 WTNT41 KNHC 301432 TCDAT1 TROPICAL STORM JERRY DISCUSSION NUMBER 7 NWS NATIONAL HURRICANE CENTER MIAMI FL AL112013 1100 AM AST MON SEP 30 2013 DEEP CONVECTION HAS BECOME MORE PERSISTENT...AND VISIBLE SATELLITE IMAGES INDICATE THAT THE LOW-LEVEL CENTER IS NEAR THE WESTERN EDGE OF THE MAIN AREA OF CONVECTION. DVORAK INTENSITY ESTIMATES FROM TAFB AND SAB ARE BOTH 35 KT...AND THE CYCLONE IS BEING UPGRADED TO A TROPICAL STORM ON THIS ADVISORY. WATER VAPOR IMAGERY SHOWS DIFFLUENT UPPER-LEVEL FLOW OVER THE AREA...HOWEVER THE DYNAMICAL GUIDANCE INDICATES THAT WESTERLY TO NORTHWESTERLY VERTICAL SHEAR SHOULD CONTINUE TO AFFECT THE STORM FOR THE NEXT SEVERAL DAYS. AT THIS TIME...THE ENVIRONMENT IS NOT EXPECTED TO BE HOSTILE ENOUGH TO PREVENT AT LEAST A LITTLE STRENGTHENING DURING THE NEXT DAY OR SO. IN THE LATTER PART OF THE FORECAST PERIOD...THERE IS QUITE A BIT OF SPREAD IN THE NUMERICAL INTENSITY GUIDANCE...AND THEREFORE THE WIND SPEED FORECAST FOR THAT TIME IS OF LOW CONFIDENCE. CENTER FIXES FROM VISIBLE SATELLITE IMAGES INDICATE THAT THE STORM HAS MOVED A LITTLE MORE TO THE EAST THAN EARLIER ESTIMATED...AND THE INITIAL MOTION IS NEAR 090/6. THE DYNAMICAL MODELS CONTINUE TO PREDICT AN AMPLIFYING MID-TROPOSPHERIC RIDGE TO THE NORTHWEST AND NORTH OF JERRY OVER THE NEXT SEVERAL DAYS. THIS STEERING SCENARIO SHOULD RESULT IN THE STORM DECELERATING AND MOVING IN A CLOCKWISE LOOP DURING THE NEXT 48-72 HOURS...AS SHOWN IN THE OFFICIAL TRACK FORECAST. IN THE LATTER PART OF THE PERIOD...THE GLOBAL MODELS ARE SUGGESTING THAT JERRY MAY NOT GET PICKED UP BY THE NEXT TROUGH IN THE WESTERLIES...AND THIS IS ALSO REFLECTED IN THE CURRENT OFFICIAL FORECAST. FORECAST POSITIONS AND MAX WINDS INIT 30/1500Z 27.0N 45.7W 35 KT 40 MPH 12H 01/0000Z 26.6N 45.5W 35 KT 40 MPH 24H 01/1200Z 26.3N 45.5W 40 KT 45 MPH 36H 02/0000Z 26.2N 46.5W 40 KT 45 MPH 48H 02/1200Z 26.3N 47.9W 40 KT 45 MPH 72H 03/1200Z 27.3N 49.8W 40 KT 45 MPH 96H 04/1200Z 28.5N 49.0W 35 KT 40 MPH 120H 05/1200Z 30.5N 46.0W 35 KT 40 MPH $$ FORECASTER PASCH