ZCZC MIATCDEP3 ALL TTAA00 KNHC DDHHMM HURRICANE COSME DISCUSSION NUMBER 11 NWS NATIONAL HURRICANE CENTER MIAMI FL EP032013 800 PM PDT TUE JUN 25 2013 A BANDING EYE HAS BEEN INTERMITTENTLY PRESENT IN VISIBLE SATELLITE IMAGERY OVER THE PAST FEW HOURS...AND MICROWAVE IMAGERY INDICATES THAT COSME NEARLY HAD A CLOSED EYEWALL AROUND 0000 UTC. DVORAK ESTIMATES FROM TAFB...SAB...AND THE UW-CIMSS ADT ARE IN VERY GOOD AGREEMENT AND SUPPORT INCREASING THE INITIAL INTENSITY TO 75 KT. HOWEVER...THE WINDOW FOR INTENSIFICATION APPEARS TO BE CLOSING. COSME IS LOCATED OVER A SHARP GRADIENT IN SEA SURFACE TEMPERATURES...AND IS MOVING INTO A HOSTILE OCEANIC ENVIRONMENT. STEADY WEAKENING IS EXPECTED TO BEGIN OVERNIGHT...AND COSME IS FORECAST TO BECOME A REMNANT LOW BY 72 HOURS. COSME CONTINUES TO MOVE TOWARD THE WEST-NORTHWEST ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYER RIDGE...AND THE INITIAL MOTION IS ESTIMATED AT 290/12. WHILE THIS RIDGE SHOULD CONTINUE TO STEER COSME GENERALLY TOWARD THE WEST-NORTHWEST OVER THE NEXT 36 HOURS...THE ECMWF AND GFS SUGGEST THAT THE RIDGE MAY LIFT SLIGHTLY NORTHWARD...ALLOWING COSME TO GAIN A LITTLE LATITUDE. AFTER THAT...A TURN TOWARD THE WEST WITH A SLIGHT DECREASE IN FORWARD SPEED IS EXPECTED AS THE TROPICAL CYCLONE WEAKENS AND BECOMES INCREASINGLY INFLUENCED BY THE LOW-LEVEL EASTERLIES. THE NEW FORECAST IS VERY NEAR THE DYNAMICAL MODEL CONSENSUS AND HAS NOT CHANGED SUBSTANTIALLY FROM THE PREVIOUS FORECAST. 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 THE NEXT COUPLE OF DAYS. FORECAST POSITIONS AND MAX WINDS INIT 26/0300Z 17.9N 113.3W 75 KT 85 MPH 12H 26/1200Z 18.6N 115.2W 70 KT 80 MPH 24H 27/0000Z 19.5N 117.6W 60 KT 70 MPH 36H 27/1200Z 20.3N 120.3W 45 KT 50 MPH 48H 28/0000Z 20.9N 123.1W 35 KT 40 MPH 72H 29/0000Z 21.7N 128.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 30/0000Z 22.0N 133.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 01/0000Z 22.0N 137.5W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ FORECASTER ZELINSKY/PASCH NNNN