WDPN31 PGTW 270300 MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 25W /WARNING NR 29// RMKS/ 1. FOR METEOROLOGISTS. 2. PROGNOSTIC REASONING FOR 270000Z9 SEP TO 020000Z2 OCT 2004. A. TYPHOON (TY) 25W (MEARI), LOCATED APPROXIMATELY 170 NM WEST OF OKINAWA, JAPAN, HAS TRACKED NORTHWESTWARD AT 01 KNOT OVER THE PAST 06 HOURS. THE WARNING POSITION IS BASED ON 262330Z6 MULTISPECTRAL SATELLITE IMAGERY AND 270000Z9 RADAR IMAGERY. THE WARNING INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 102 AND 115 KNOTS. B. TY 25W HAS REMAINED ESSENTIALLY QUASISTATIONARY OVER THE PAST 06 HOURS IN A WEAKENED STEERING ENVIRONMENT BETWEEN A HIGH TO THE EAST AND A BUILDING HIGH TO THE WEST OVER CHINA. HOWEVER, THE TRACK OF TY 25W IS INDICATING THE BEGINNING OF RECURVATURE TO THE NORTHEAST. DURING THE MID-PERIOD, A SHORTWAVE TROUGH TRACKING EASTWARD FROM ASIA WILL PROVIDE STEERING INFLUENCE ASSISTING TY 25W TO RECURVE NORTHEASTWARD TOWARD JAPAN. THE AVAILABLE DYNAMIC AIDS CONSISTING OF NOGAPS, GFDN, UKMET EGRR, JGSM, JTYM, NCEP GFS, COAMPS, TCLAPS, AFWA MM5 AND WBAR ARE IN FAIR AGREEMENT WITH THIS FORECAST SCENARIO THROUGH 72 HOURS. GFDN IS AN EQUATORWARD OUTLIER, FORECASTING THE BUILDING OF A RIDGE POLEWARD OF TY 25W AND A WESTWARD TRACK. THE CURRENT FORECAST IS BASED ON A BLEND OF THE AVAILABLE DYNAMIC MODELS WITH LESS EMPHASIS ON GFDN. C. TY 25W HAS TEMPORARILY REINTENSIFIED IN AN ENVIRONMENT OF WEAK VERTICAL WIND SHEAR AND FAVORABLE UPPER LEVEL DIFFLUENCE AS IT SLOWS PRIOR TO RECURVATURE. TY 25W IS FORECAST TO SLOWLY WEAKEN AS DRIER AIR INTRUDES FROM THE WEST AND THE SYSTEM TRACKS POLEWARD INTO AN ENVIRONMENT OF LESS FAVORABLE VERTICAL WIND SHEAR. D. CURRENT AND FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR A SMALL TO AVERAGE SIZED SYSTEM AND A 262132Z6 QUICKSCAT IMAGE. E. IN THE EXTENDED FORECAST, TY 25W IS FORECAST TO TRACK NORTHEASTWARD INTO SOUTHERN JAPAN AND CONTINUE TO WEAKEN DUE TO LAND INTERACTION AND INCREASED VERTICAL WIND SHEAR. THE UKMET EGRR AND GFDN MODELS INDICATE A BUILDING RIDGE CENTERED OVER THE YELLOW SEA THAT TRACKS THE SYSTEM WEST-SOUTHWESTWARD WHICH IS CONSIDERED LESS LIKELY. THIS FORECAST IS BASED ON A BLEND OF THE AVAILABLE DYNAMIC MODELS WITH LESS EMPHASIS ON UKMET EGRR AND GFDN. 3. FORECAST TEAM: DIXON/MENEBROKER/TINOCO/FUNK/JAYKOSKI// NNNN