000 WTPZ41 KNHC 160231 TCDEP1 TROPICAL STORM COSME DISCUSSION NUMBER 7 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP062007 800 PM PDT SUN JUL 15 2007 COSME IS GETTING BETTER ORGANIZED. AN AMSR-E OVERPASS AT 2200 UTC SUGGESTED THE DEVELOPMENT OF A TIGHTER INNER CORE...AND SUBSEQUENT CONVENTIONAL IMAGERY SHOWS A SIGNIFICANT INCREASE IN CONVECTION NEAR THE CENTER. SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB ARE NOW 45 KT...AND THAT IS THE INITIAL INTENSITY. THE INITIAL MOTION REMAINS 305/7. LARGE-SCALE MODEL ANALYSES SHOW A WEAKNESS IN THE MID/UPPER-LEVEL SUBTROPICAL RIDGE NORTH OF COSME...WITH SATELLITE IMAGERY SHOWING A WELL-DEFINED LOW-LEVEL RIDGE NORTH OF THE STORM. THIS PATTERN SHOULD STEER COSME GENERALLY WEST-NORTHWESTWARD FOR 24 HR OR SO...FOLLOWED BY A MORE WESTWARD MOTION AS THE MID/UPPER-LEVEL RIDGE STRENGTHENS SOMEWHAT. WHILE ALL TRACK GUIDANCE AGREES WITH THIS GENERAL SCENARIO...THE UKMET...ECMWF...AND BAM MODELS CALL FOR MORE NORTHWARD MOTION IN THE FIRST 24 HR BEFORE THE WESTWARD TURN. THE GFS...GFDL...HWRF... AND CONSENSUS MODELS CALL FOR LESS NORTHWARD MOVEMENT BEFORE THE TURN...AND THE NEW FORECAST TRACK FOLLOWS THESE MODELS. ALL THE GUIDANCE CALLS FOR A FASTER MOTION AFTER 36 HR THAN THE PREVIOUS RUNS...SO THE FORECAST FORWARD SPEED HAS BEEN INCREASED SOMEWHAT. IT SHOULD BE NOTED THAT COSME IS EMBEDDED IN A LARGE CYCLONIC GYRE THAT INCLUDES THE REMAINS OF TROPICAL DEPRESSION 5-E...AND THIS MAY PRODUCE SOME TRACK WOBBLES DURING THE FIRST 24-36 HR. COSME IS IN AN ENVIRONMENT OF LIGHT SOUTHEASTERLY VERTICAL SHEAR... AND THE CYCLONE SHOULD REMAIN IN A FAVORABLE SHEAR ENVIRONMENT FOR AT LEAST THE NEXT FOUR DAYS. THUS...THE INTENSITY WILL BE CONTROLLED MAINLY BY THE SEA SURFACE TEMPERATURES. SST ANALYSES INDICATE THAT THE STORM IS OVER 27C TEMPERATURES...WHICH SHOULD COOL ALONG THE FORECAST TRACK AFTER 12-24 HR. THIS SHOULD ALLOW COSME SOME ADDITIONAL STRENGTHENING BEFORE GRADUAL WEAKENING BEGINS IN 36 HR OR SO. SHIPS FORECAST COSME TO BECOME A HURRICANE...WHILE THE GFDL AND HWRF DO NOT. THE INTENSITY FORECAST HAS BEEN INCREASED...NOW CALLING FOR COSME TO PEAK AT 60 KT IN 24 HR AS A COMPROMISE BETWEEN SHIPS AND THE GFDL/HWRF. IF THE CURRENT CONVECTIVE TRENDS CONTINUE...THERE IS A CHANCE COSME COULD BECOME A HURRICANE BEFORE WEAKENING BEGINS. THE FORECAST WIND RADII HAVE BEEN INCREASED BASED ON THE INCREASED FORECAST INTENSITY. FORECAST POSITIONS AND MAX WINDS INITIAL 16/0300Z 13.3N 128.8W 45 KT 12HR VT 16/1200Z 13.8N 129.9W 55 KT 24HR VT 17/0000Z 14.5N 131.6W 60 KT 36HR VT 17/1200Z 14.8N 133.4W 60 KT 48HR VT 18/0000Z 15.0N 135.5W 55 KT 72HR VT 19/0000Z 15.5N 140.5W 50 KT 96HR VT 20/0000Z 16.5N 146.0W 40 KT 120HR VT 21/0000Z 17.5N 151.0W 30 KT $$ FORECASTER BEVEN