000 WTPZ43 KNHC 261447 TCDEP3 TROPICAL STORM COSME DISCUSSION NUMBER 13 NWS NATIONAL HURRICANE CENTER MIAMI FL EP032013 800 AM PDT WED JUN 26 2013 COSME HAS BEGUN ITS WEAKENING PHASE...AS MICROWAVE SATELLITE IMAGERY INDICATE THAT THE EYE IS NO LONGER CLOSED. BASED UPON THE INFRARED GEOSTATIONARY IMAGERY...THE TAFB AND DVORAK INTENSITY ESTIMATES HAVE DROPPED TO 3.0/4.0...WHILE THE CIMSS ADVANCED DVORAK TECHNIQUE INDICATES T3.7 OR 55-60 KT. THE INTENSITY IS ANALYZED TO BE 60 KT...JUST BELOW HURRICANE FORCE. A 0937Z AMSU SATELLITE PASS PROVIDED GUIDANCE ON THE TROPICAL STORM WIND RADII...WHICH HAS BEEN EXPANDED OUTWARD SLIGHTLY BASED UPON THE CIRA SIZE ANALYSIS. THE AFOREMENTIONED AMSU PASS ALONG WITH AN 1106Z SSMI PASS ALLOW FOR A FAIRLY CONFIDENT ASSESSMENT OF THE INITIAL POSITION OF COSME. THE CYCLONE IS MOVING WEST-NORTHWEST AT 12 KT...DUE TO THE STEERING INFLUENCE OF A DEEP-LAYER RIDGE TO ITS NORTH. COSME SHOULD CONTINUE WEST-NORTHWESTWARD FOR THE NEXT 36-48 HOURS BEFORE BENDING WESTWARD THEREAFTER. THE TRACK GUIDANCE IS TIGHTLY CLUSTERED AND HAS SHIFTED SLIGHTLY NORTHWARD...IN PART DUE TO A MORE NORTHERLY INITIAL POSITION. THE TRACK PREDICTION IS LIKEWISE SLIGHTLY NORTH OF THE PREVIOUS ADVISORY. WHILE COSME SHOULD CONTINUE TO EXPERIENCE LOW VERTICAL WIND SHEAR WITHIN A MOIST ENVIRONMENT...THE CYCLONE SHOULD QUICKLY DECAY DUE TO TRAVERSING COLD WATER. EVEN THOUGH THE DEEP CONVECTION IS CURRENTLY QUITE VIGOROUS...WHEN COSME REACHES 22C SSTS TOMORROW THE CONVECTION IS LIKELY TO COLLAPSE...AND THE SYSTEM IS EXPECTED BECOME A REMNANT LOW IN ABOUT 36 HOURS. THE INTENSITY PREDICTION IS CLOSE TO THE VARIABLE CONSENSUS TECHNIQUE AND IS A BIT BELOW THE PREVIOUS ADVISORY. THE EXTENSIVE 12-FT SEAS RADII ARE THE RESULT OF LONG-FETCH SOUTHERLY CROSS-EQUATORIAL FLOW GENERATING LARGE SWELLS...WHICH WILL CONTINUE TO AFFECT MUCH OF THE SOUTHWESTERN PACIFIC COAST OF MEXICO AND THE SOUTHERN BAJA CALIFORNIA PENINSULA DURING DAY OR SO. FORECAST POSITIONS AND MAX WINDS INIT 26/1500Z 19.1N 115.6W 60 KT 70 MPH 12H 27/0000Z 19.9N 117.5W 50 KT 60 MPH 24H 27/1200Z 20.8N 120.3W 40 KT 45 MPH 36H 28/0000Z 21.8N 123.1W 30 KT 35 MPH...POST-TROP/REMNT LOW 48H 28/1200Z 22.3N 125.9W 25 KT 30 MPH...POST-TROP/REMNT LOW 72H 29/1200Z 22.5N 131.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 30/1200Z 22.5N 135.0W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 01/1200Z 22.5N 138.0W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ FORECASTER LANDSEA