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#635801 (Received by flhurricane at: 4:38 AM 02.Oct.2013) TCDAT1 TROPICAL STORM JERRY DISCUSSION NUMBER 14 NWS NATIONAL HURRICANE CENTER MIAMI FL AL112013 500 AM AST WED OCT 02 2013 DEEP CONVECTION ASSOCIATED WITH JERRY HAS INCREASED A LITTLE THIS MORNING...MAINLY IN BANDS OVER THE NORTHEASTERN SEMICIRCLE. WATER VAPOR IMAGERY AND EXPERIMENTAL MULTISPECTRAL AIRMASS IMAGERY SUGGEST THAT THE CYCLONE IS UNDERNEATH A SMALL UPPER-LEVEL LOW...WITH DRY AIR ENTRAINING INTO THE CIRCULATION IN THE SOUTHWESTERN SEMICIRCLE. THERE ARE NO RECENT SCATTEROMETER OVERPASSES...AND THE SATELLITE INTENSITY ESTIMATES ARE UNCHANGED FROM 6 HOURS AGO. BASED ON THIS...THE INITIAL INTENSITY REMAINS 35 KT. THE INITIAL MOTION IS A WESTWARD DRIFT OR 270/1. JERRY IS CURRENTLY SOUTH OF A RIDGE IN THE WESTERLIES. A LARGE DEEP-LAYER CYCLONE CURRENTLY SOUTH OF EASTERN CANADA IS FORECAST TO MOVE EASTWARD AND WEAKEN THIS RIDGE LATER TODAY...WHICH SHOULD CAUSE JERRY TO BECOME EMBEDDED IN SOUTHWESTERLY FLOW AND MOVE NORTHEASTWARD AS SHOWN BY ALL OF THE GLOBAL MODELS. THE TRACK GUIDANCE IS TIGHTLY CLUSTERED IN TERMS OF DIRECTION...ALTHOUGH THERE IS SOME SPREAD IN SPEED BETWEEN THE SLOWER ECMWF AND THE OTHER MODELS. THE NEW FORECAST TRACK IS AN UPDATE OF THE PREVIOUS FORECAST. THE FORECAST MOTION BRINGS JERRY OVER DECREASING SEA SURFACE TEMPERATURES AND INCREASING VERTICAL WIND SHEAR...WHICH SHOULD CAUSE THE SYSTEM TO DECAY. INDEED...THE GLOBAL MODELS ARE IN GOOD AGREEMENT THAT JERRY WILL WEAKEN TO A TROUGH BY THE 72 HOUR POINT. THE INTENSITY FORECAST FOLLOWS THE CONSENSUS MODELS AND THE PREVIOUS FORECAST IN SHOWING LITTLE CHANGE IN STRENGTH THROUGH 72 HOURS. AFTER THAT...THE CYCLONE IS FORECAST TO DEGENERATE TO A REMNANT LOW BY 96 HOURS AND SUBSEQUENTLY DISSIPATE. AN ALTERNATIVE SCENARIO IS THAT JERRY DISSIPATES MUCH EARLIER AS FORECAST BY THE GLOBAL MODELS. FORECAST POSITIONS AND MAX WINDS INIT 02/0900Z 28.1N 44.0W 35 KT 40 MPH 12H 02/1800Z 28.9N 43.5W 35 KT 40 MPH 24H 03/0600Z 29.9N 42.5W 35 KT 40 MPH 36H 03/1800Z 31.1N 40.6W 35 KT 40 MPH 48H 04/0600Z 32.2N 38.1W 35 KT 40 MPH 72H 05/0600Z 34.5N 33.0W 35 KT 40 MPH 96H 06/0600Z 38.0N 27.5W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 07/0600Z...DISSIPATED $$ FORECASTER BEVEN |