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#632909 (Received by flhurricane at: 10:50 PM 17.Sep.2013) TCDAT4 TROPICAL STORM HUMBERTO DISCUSSION NUMBER 31 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092013 1100 PM AST TUE SEP 17 2013 THE TROPICAL STORM IS NOT WELL ORGANIZED THIS EVENING. ONLY SOME FRAGMENTED BANDS ARE ON THE EASTERN SIDE OF THE ELONGATED CIRCULATION...WITH THE CENTER ON THE SOUTHWESTERN SIDE OF THE CONVECTION. AN ASCAT PASS SHOWED A SMALL AREA OF 30-35 KT WINDS... AND 35 KT IS USED AS THE INITIAL INTENSITY. SOME INCREASE IN STRENGTH IS POSSIBLE WHILE THE SHEAR REMAINS LOW AND HUMBERTO REMAINS OVER MARGINAL SSTS DURING THE NEXT COUPLE OF DAYS. SHIPS/ LGEM ARE HIGHER THAN MOST OF THE GUIDANCE AND SHOW HUMBERTO CLOSE TO A HURRICANE AGAIN...ALTHOUGH THE CURRENT AND FORECAST SSTS FROM SHIPS SEEM TOO HIGH COMPARED WITH AVAILABLE OBSERVATIONS. THUS... THE OFFICIAL FORECAST STILL REMAINS ON THE CONSERVATIVE SIDE... CLOSE TO A BLEND OF THE PREVIOUS FORECAST AND THE INTENSITY CONSENSUS. THE INITIAL MOTION HAS BEEN CHALLENGING TO DETERMINE SINCE THE CIRCULATION IS NOT VERY COMPACT...BUT IS ESTIMATED AT 345/6. A TROUGH OVER THE WESTERN ATLANTIC OCEAN SHOULD TURN HUMBERTO TO THE NORTH THEN NORTHEAST OVER THE NEXT COUPLE OF DAYS WITH A SIGNIFICANT INCREASE IN FORWARD SPEED IN THE 48-72H PERIOD. MOST OF THE GLOBAL MODELS SHOW THIS SYSTEM BECOMING EXTRATROPICAL IN ABOUT 3 DAYS...AND ABSORBED WITHIN A LARGER MID-LATITUDE LOW IN 4-5 DAYS. THE GUIDANCE IS VERY TIGHTLY PACKED AND NO SIGNIFICANT CHANGES WERE MADE TO THE PREVIOUS NHC FORECAST. FORECAST POSITIONS AND MAX WINDS INIT 18/0300Z 30.8N 43.3W 35 KT 40 MPH 12H 18/1200Z 31.6N 43.4W 35 KT 40 MPH 24H 19/0000Z 32.8N 43.4W 40 KT 45 MPH 36H 19/1200Z 34.3N 42.7W 40 KT 45 MPH 48H 20/0000Z 36.3N 41.2W 45 KT 50 MPH 72H 21/0000Z 43.0N 35.0W 50 KT 60 MPH...POST-TROP/EXTRATROP 96H 22/0000Z 54.5N 24.5W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 23/0000Z...ABSORBED $$ FORECASTER BLAKE |