WDPN32 PGTW 091500 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 09W WARNING NR 24// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TROPICAL STORM (TS) 09W (MORAKOT) HAS SLOWLY TRACKED ACROSS THE TAIWAN STRAIT AND MADE LANDFALL IN THE FUJIAN PROVINCE OF CHINA. RECENT ANIMATED INFRARED IMAGERY SHOWS A VERY LARGE CIRCULATION WITH DEEP CONVECTION ALONG THE WESTERN AND SOUTHERN SIDES, BUT WITH LIMITED CONVECTION NEAR THE CENTER. ALSO EVIDENT IN ANIMATED INFRARED AND WATER VAPOR IMAGERY IS A VERY WELL DEFINED RADIAL OUTFLOW PATTERN IN THE UPPER LEVELS. ENVIRONMENTAL ANALYSIS INDICATES THAT 09W IS LOCATED SOUTH OF THE UPPER LEVEL RIDGE AXIS, BUT NEAR AN UPPER LEVEL OUTFLOW SOURCE THAT IS CONTRIBUTING GREATLY TO THE LOW VERTICAL WINDSHEAR AND HEALTHY OUTFLOW. THE SYSTEM IS CURRENTLY BETWEEN THE COMPETING STEERING FLOWS OF THE SOUTHWEST MONSOONAL FLOW AND THE NORTHEASTERLY FLOW ASSOCIATED WITH THE EASTERN EXTENT OF THE LOW- TO MID-LEVEL SUBTROPICAL RIDGE (STR) OVER MAINLAND CHINA. POSITION IS BASED ON A FIX BY PGTW WITH POOR CONFIDENCE DUE TO THE POOR DEFINITION OF THE SYSTEM OVER LAND. 3. FORECAST REASONING. A. THE FORECAST PHILOSOPHY HAS NOT SIGNIFICANTLY CHANGED SINCE THE LAST PROGNOSTIC REASONING BULLETIN. B. AS THE STR BECOMES ERODED BY THE PASSAGE OF A MID-LATITUDE TROUGH, THE SYSTEM IS EXPECTED TO TRACK TO THE NORTH. THE SYSTEM IS EXPECTED TO CONTINUE WEAKENING AS IT TRACKS OVER LAND. DISSIPATION IS FORECASTED TO OCCUR BY TAU 24. MODEL GUIDANCE INDICATES THAT THE REMNANTS OF TS 09W WILL BE ABSORBED INTO A MID-LATITUDE TROUGH AS IT APPROACHES THE EAST CHINA SEA BETWEEN TAU 36 AND TAU 72. FORECAST TEAM: ECHO// NNNN