WDPN31 PGTW 221500 MSGID/GENADMIN/NAVPACMETOCCEN PEARL//JTWC// SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON (STY) 12W (FENGSHEN) WARNING NR 34// RMKS/ 1. FOR METEOROLOGISTS. 2. PROGNOSTIC REASONING FOR 221200Z7 TO 251200Z0 JUL 02. A. SUPER TYPHOON (STY) 12W (FENGSHEN), LOCATED APPROXIMATELY 475 NM EAST OF IWO JIMA, HAS TRACKED NORTHWESTWARD AT 14 KNOTS OVER THE PAST SIX HOURS. THE WARNING POSITION IS BASED ON 221130Z9 ENHANCED INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 127 AND 140 KNOTS. A 221127Z5 SSM/I PASS DEPICTS AN IRREGULAR EYE AND A LARGE RAIN BAND EXTENDING INTO THE EASTERN SEMI-CIRCLE. B. THE MID-LEVEL SUBTROPICAL RIDGE NORTH OF THE SYSTEM IS EXPECTED TO CONTINUE TO PROPAGATE EASTWARD AS STY 12W BUILDS A BETA RIDGE AND BEGINS TO MODIFY THE STEERING ENVIRONMENT BY 72 HOURS. STY 12W IS EXPECTED TO TRACK NORTHWESTWARD THROUGH 36 HOURS AND THEN WEST-NORTHWESTWARD AS THE SYSTEM BEGINS TO INTERACT WITH TS 14W. THE TWO SYSTEMS WILL BEGIN TO SLOWLY ROTATE CYCLONICALLY AS A RESULT OF THIS INTERACTION BY THE END OF THE PERIOD. THE AVAILABLE DYNAMIC AIDS CONSIST OF NCEP AVIATION (AVN), GFDN, NOGAPS (NGPS), AFWA MM5, COAMPS, UKMET OFFICE GLOBAL (EGRR), AND THE JAPANESE GLOBAL (JGSM) AND TYPHOON (JTYM) MODELS. THE DYNAMIC AIDS ARE IN TWO CLUSTERS. THE FIRST CLUSTER CONSISTS OF NGPS, GFDN, AND COAMPS. THESE MODELS DEVELOP A STRONGER BETA RIDGE BY MID PERIOD, CAUSING THE TRACK TO SLOW AND RECURVE AS THE BETA RIDGE LINKS UP WITH THE SUBTROPICAL RIDGE. THE OTHER AIDS KEEP THE BETA RIDGE SMALLER AND WEAKEN THE SUBTROPICAL RIDGE LATE IN THE PERIOD. OUR FORECAST IS BASED ON A BLEND OF ALL AVAILABLE DYNAMIC AIDS. C. STY 12W HAS REACHED MAXIMUM INTENSITY AND IS FORECAST TO SLOWLY WEAKEN THROUGH IN THE PERIOD. THE SYSTEM IS EXPECTED TO ENCOUNTER INCREASING VERTICAL WIND SHEAR FROM UPPER LEVEL SOUTHWESTERLIES BY 72 HOURS. D. INITIAL WIND RADII IS BASED ON A 220812Z5 QUIKSCAT PASS. FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE SYSTEM. 3. FORECAST TEAM: WINGEART/LAM/KUMAGA/TON// BT #XXXX NNNN