WDPN31 PGTW 301500 COR MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 30W /WARNING NR 08A CORRECTED// RMKS/ 1. FOR METEOROLOGISTS. 2. PROGNOSTIC REASONING FOR 301200Z6 NOV TO 051200Z8 DEC 2004. A. TYPHOON (TY) 30W (NANMADOL), LOCATED APPROXIMATELY 75 NM WEST-NORTHWEST OF YAP, HAS TRACKED WEST-NORTHWESTWARD AT 22 KNOTS OVER THE PAST 06 HOURS. THE WARNING POSITION IS BASED ON 301130Z8 ENHANCED INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 77 AND 90 KNOTS. B. TY 30W IS FORECAST TO TRACK WEST-NORTHWESTWARD ALONG THE SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL RIDGE ANCHORED TO THE NORTHEAST. TY 30W IS FORECAST TO MAKE LANDFALL IN THE NORTHERN PHILIPPINES BETWEEN TAUS 48 AND 72. AS THE SYSTEM ENTERS THE SOUTH CHINA SEA, THE TRACK WILL BEGIN TO TURN MORE POLEWARD IN RESPONSE TO A DEVELOPING WEAKNESS IN THE STEERING RIDGE. THE AVAILABLE DYN- AMIC AIDS CONSISTING OF NOGAPS, COAMPS, GFDN, NCEP GFS, JGSM, JTYM, TCLAPS, UKMET, AND WBAR ARE IN GOOD AGREEMENT WITH THIS SCENARIO, THOUGH THE TIMING OF THE ONSET OF RECURVATURE VARIES SLIGHTLY. THIS FORECAST IS BASED ON A CONSENSUS OF ALL AVAILABLE DYNAMIC AIDS. C. THE INTENSITY OF TY 30W IS FORECAST TO INCREASE AT A CLIMATO- LOGICAL RATE THROUGH TAU 48 IN AN ENVIRONMENT OF LOW TO MODERATE VERTICAL WIND SHEAR BALANCED BY GOOD RADIAL OUTFLOW. THE INTENSITY IS FORECAST TO DECREASE SLOWLY AFTER TAU 48 AS THE SYSTEM INTERACTS WITH LAND AND ENTERS AN ENVIRONMENT OF STRONGER VERTICAL WIND SHEAR. D. CURRENT WIND RADII ARE BASED ON A 300902Z4 QUIKSCAT PASS AND A 300842Z7 WINDSAT MICROWAVE PASS. FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR A LARGE SIZED SYSTEM. E. THE LONGWAVE TROUGH CURRENTLY OVER CHINA WILL PROVIDE A WEAK- NESS IN THE STEERING RIDGE LATER IN THE FORECAST PERIOD THAT WILL ALLOW TY 30W TO TURN POLEWARD AFTER TAU 72. TY 30W WILL WEAKEN IN INTENSITY AFTER TAU 72 AS IT ENCOUNTERS INCREASED VERTICAL WIND SHEAR IN THE SOUTH CHINA SEA. A BRIEF INCREASE IN INTENSITY IS POSSIBLE AS THE SYSTEM CRESTS THE RIDGE AXIS AND INTERACTS WITH THE LONGWAVE TROUGH. TY 30W IS FORECAST TO BEGIN THE INITIAL STAGES OF EXTRATROPICAL TRANSITION LATE IN THE FORECAST PERIOD AS THE SYSTEM TRACKS NORTHEASTWARD AFTER TAU 96 AND BECOMES EMBEDDED IN THE MID- LATITUDE WESTERLIES. 3. JUSTIFICATION FOR CORRECTION: ADJUSTED PROGNOSTIC REASONING TO REFLECT UPDATED REMARKS 4. FORECAST TEAM: BOWER/LAM/HEILER//