WDPN32 PGTW 051500 1. FOR METEOROLOGISTS. 2. PROGNOSTIC REASONING FOR 051200Z8 TO 081200Z1 SEP 02. A. TYPHOON (TY) 22W, LOCATED APPROXIMATELY 115 NM WEST OF KADENA, OKINAWA HAS TRACKED WESTWARD AT 04 KNOTS DURING THE PAST 6 HOURS. THE WARNING POSITION IS BASED ON 051130Z0 ENHANCED INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 90 AND 102 KNOTS. A 051119Z7 SSM/I INDICATES THE DEEP CONVECTION IS IN THE NORTHERN QUADRANTS AND THAT THE SOUTERN EYEWALL IS WEAKENING. B. A LONGWAVE TROUGH OVER THE NORTHERN PORTION OF THE YELLOW SEA IS NOW DIRECTLY POLEWARD OF THE SYSTEM. AS THE TROUGH MOVES EASTWARD THE MID-LEVEL SUBTROPICAL RIDGE OVER EASTERN CHINA IS EXPECTED TO BUILD IN. TY 22W IS EXPECTED TO CONTINUE MOVING WESTWARD AND SHOULD PICK UP SPEED AS THE RIDGE BUILDS GUIDING TY 22W TO TRACK JUST NORTH OF TAIWAN AND THEN LATER INTO SOUTHEASTERN CHINA. THE AVAILABLE DYNAMICAL MODELS CONSIST OF NCEP AVIATION (AVN), NOGAPS, UKMET GLOBAL (EGRR), AFWA MM5, COAMPS, AND THE JMA GLOBAL (JGSM) AND TYPHOON (JTYM) MODELS. ALL MODELS ARE IN GOOD AGREEMENT THROUGH 48 HOURS. COAMPS AND MM5 DO NOT STRENGTHEN THE SUBTROPICAL RIDGE AS MUCH AS THE OTHER AIDS, CAUSING THE SYSTEM TO TRACK MORE POLEWARD. JTYM AND JGSM DIP THE SYSTEM DOWN INTO THE SOUTH CHINA SEA AFTER 48 HOURS SUGGESTING EXCESSIVE INTERACTION WITH THE MONSOON TROUGH. OUR FORECAST IS BASED ON A BLEND OF ALL AVAILABLE DYNAMIC AIDS WITH LESS EMPHASIS ON JTYM AND JGSM AFTER 48 HOURS. C. TY 22W IS FORECAST TO SLOWLY WEAKEN THROUGH THE PERIOD AS IT TRACKS INTO THE SOUTHEAST QUADRANT OF THE UPPER LEVEL RIDGE AND ENCOUNTERS INCREASING VERTICAL WIND SHEAR. D. INITIAL WIND RADII ARE BASED ON SYNOPTIC OBSERVATIONS AND SATELLITE ANALYSIS. FORECAST WIND FORECAST RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE-SIZED SYSTEM. 3. FORECAST TEAM: LEEJOICE/HEATH/BOSTIC/DUKES// NNNN