ZCZC MIATCDAT1 ALL TTAA00 KNHC DDHHMM TROPICAL STORM JERRY DISCUSSION NUMBER 8 NWS NATIONAL HURRICANE CENTER MIAMI FL AL112013 500 PM AST MON SEP 30 2013 ALTHOUGH CLOUD TOPS HAVE BEEN WARMING RECENTLY...SOME CONVECTIVE BANDING FEATURES HAVE FORMED OVER THE EASTERN SEMICIRCLE OF THE CIRCULATION. THE CENTER IS NOT READILY DISCERNABLE...BUT IS ESTIMATED TO BE LOCATED NEAR THE SOUTHWESTERN EDGE OF THE MAIN CLOUD MASS. DVORAK T-NUMBERS FROM BOTH TAFB AND SAB REMAIN AT 2.5...SO THE ADVISORY INTENSITY IS HELD AT 35 KT. ALTHOUGH THE ENVIRONMENT...IN PARTICULAR THE VERTICAL SHEAR...IS EXPECTED TO BE ONLY MARGINALLY CONDUCIVE FOR INTENSIFICATION OVER THE NEXT SEVERAL DAYS...SOME SLIGHT STRENGTHENING IS POSSIBLE. THIS IS INDICATED IN THE OFFICIAL WIND SPEED FORECAST...WHICH IS CLOSE TO THE MODEL CONSENSUS FOR THE FIRST HALF OF THE FORECAST PERIOD. LATER IN THE PERIOD...THE OFFICIAL FORECAST IS A COMPROMISE BETWEEN THE SEEMINGLY OVER-AGGRESSIVE LGEM AND THE GLOBAL AND HWRF MODELS THAT SHOW DISSIPATION OR A VERY WEAK SYSTEM BY 5 DAYS. JERRY HAS CONTINUED TO MOVE EASTWARD...085/6...BUT THIS MOTION IS NOT LIKELY TO CONTINUE MUCH LONGER. THE GLOBAL MODELS PREDICT A MID-LEVEL RIDGE TO BUILD TO THE NORTHWEST AND NORTH OF JERRY OVER THE NEXT FEW DAYS. AS DISCUSSED EARLIER...MUCH OF THE TRACK GUIDANCE INDICATES THAT THIS WILL RESULT IN JERRY MOVING IN A CLOCKWISE LOOP DURING THE NEXT 2-3 DAYS. LATER IN THE FORECAST PERIOD...THE CYCLONE COULD BE CARRIED NORTHEASTWARD BY THE NEXT 500 MB TROUGH IN THE WESTERLIES. THE OFFICIAL FORECAST ASSUMES JERRY WILL REMAIN A TROPICAL CYCLONE THROUGH 4-5 DAYS...AND RESPOND TO THE MID-LEVEL STEERING FLOW. AN ALTERNATIVE SCENARIO...SHOWN BY THE ECMWF MODEL...IS FOR JERRY TO WEAKEN TO A LOW-LEVEL TROUGH BY THAT TIME AND DRIFT GENERALLY WESTWARD. FORECAST POSITIONS AND MAX WINDS INIT 30/2100Z 27.3N 44.9W 35 KT 40 MPH 12H 01/0600Z 27.0N 44.7W 35 KT 40 MPH 24H 01/1800Z 26.7N 45.4W 40 KT 45 MPH 36H 02/0600Z 26.7N 46.7W 40 KT 45 MPH 48H 02/1800Z 27.2N 47.8W 40 KT 45 MPH 72H 03/1800Z 28.5N 49.0W 40 KT 45 MPH 96H 04/1800Z 30.0N 48.0W 35 KT 40 MPH 120H 05/1800Z 32.0N 45.0W 35 KT 40 MPH $$ FORECASTER PASCH NNNN