WDPN32 PGTW 091500 RTD MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON (STY) 15W (MAEMI) /WARNING NR 16// RMKS/ 1. FOR METEOROLOGISTS. 2. PROGNOSTIC REASONING FOR 091200Z2 TO 141200Z8 SEP 2003. A. SUPER TYPHOON (STY) 15W (MAEMI), LOCATED APPROXIMATELY 205 NM SOUTH-SOUTHEAST OF OKINAWA, JAPAN, HAS TRACKED NORTH- WESTWARD AT 08 KNOTS OVER THE PAST 06 HOURS. THE WARNING POSITION IS BASED ON 091130Z4 ENHANCED INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 102 AND 140 KNOTS. A 091015Z6 SSM/I PASS DEPICTS A 24 NM EYE. B. STY 15W IS FORECAST TO CONTINUE STEERING NORTHWESTWARD UNDER THE INFLUENCE OF THE MID-LEVEL RIDGE NORTH-NORTHEAST OF THE SYSTEM FOR THE NEXT 36 HOURS. A SHORTWAVE TROUGH, CURRENTLY OVER EASTERN CHINA, IS EXPECTED TO WEAKEN THE MID-LEVEL RIDGE IN 24 TO 36 HOURS AND SHIFT THE TRACK POLEWARD. STY 15W WILL THEN LINK UP WITH THE SHORTWAVE AND ACCELERATE NORTHEASTWARD PASSING JUST WEST OF KYUSHU, JAPAN. THE AVAILABLE DYNAMIC AIDS, CONSISTING OF NOGAPS, COAMPS, UKMET (EGRR), JGSM, JTYM, NCEP GFS, AND GFDN ARE IN FAIR AGREEMENT ON THE FORECAST TRACK. EGRR AND JGSM ARE FASTER THAN THE OTHER AIDS DUE TO MORE VIGOROUS INTERACTION WITH THE BAROCLINIC ZONE. THIS FORECAST IS BASED ON A CONSENSUS OF THE AVAILABLE OBJECTIVE AIDS, WITH LESS EMPHASIS ON EGRR AND JGSM. C. STY 15W IS EXPECTED TO REACH MAX INTENSITY AS IT SLOWS AND TURNS POLEWARD WITHIN THE NEXT 24 HOURS. STY 15W IS EXPECTED TO WEAKEN AS IT TRACKS NORTHEASTWARD, ENTRAINS DRY AIR, AND ENCOUNTERS INCREASING VERTICAL SHEAR FROM THE UPPER-LEVEL WESTERLIES. D. CURRENT WIND RADII AND FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE SIZED SYSTEM. E. THE EXTENDED FORECAST CALLS FOR STY 15W TO TRACK NORTHEASTWARD INTO THE SEA OF JAPAN WHILE ENCOUNTERING COOLER SEA SURFACE TEMPERATURES AND HEADING TOWARD HOKKAIDO, JAPAN. STY 15W IS EXPECTED TO COMPLETE EXTRATROPICAL TRANSITION BY 120 HOURS. 3. FORECAST TEAM: WINGEART/DAMRON/PIVIN/ALLEN/LAM/ANDERSON// NNNN