WDPN32 PGTW 030300 
MSGID/GENADMIN/NAVPACMETOCCEN PEARL//JTWC// 
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (RAMMASUN) WARNING 
NR 20// 
RMKS/ 
1. FOR METEOROLOGISTS. 
2. PROGNOSTIC REASONING FOR 030000Z3 TO 060000Z6 JUL 02. 
   A. TYPHOON (TY) 09W (RAMMASUN), LOCATED APPROXIMATELY 190 NM 
SOUTH-SOUTHWEST OF KADENA, OKINAWA, HAS TRACKED NORTHWESTWARD AT 14 
KNOTS OVER THE PAST 6 HOURS. THE WARNING POSITION IS BASED ON 
022330Z0 VISIBLE AND INFRARED SATELLITE IMAGERY. THE WARNING 
INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 102 
and 115 KNOTS. ANIMATED INFRARED SATELLITE IMAGERY INDICATES THAT 
THE CONVECTION HAS DECREASED IN THE NORTHWESTERN QUADRANT AS THE 
SYSTEM TRACKS TOWARD SHANGHAI. A 022140Z9 SSM/I PASS DEPICTS A 
WEAKENED EYEWALL AND A LARGE RAIN BAND IN THE SOUTHERN SEMI-CIRCLE.
   B. TY 09W IS EXPECTED TO CONTINUE TRACKING NORTHWESTWARD OVER 48 
HOURS ALONG THE MID-LEVEL RIDGE NORTHEAST OF THE SYSTEM, AND THEN 
NORTHWARD INTO A WEAKNESS IN THE SUBTROPICAL RIDGE. THE AVAILABLE 
DYNAMIC AIDS CONSISTING OF GFDN, UK MET (EGRR), NOGAPS, AFWA MM5, 
NCEP AVIATION (AVN), AND THE JAPANESE GLOBAL (JGSM) MODELS AGREE 
WITH THIS SCENARIO. OUR FORECAST IS BASED ON A BLEND OF ALL 
AVAILABLE DYNAMIC AIDS.
   C. TY 09W IS EXPECTED TO PEAK BY 36 HOURS IN A FAVORABLE UPPER 
LEVEL ENVIRONMENT. AFTERWARDS, TY 09W IS EXPECTED SLOWLY WEAKEN AS 
IT ENCOUNTERS COOLER SEA SURFACE TEMPERATURES AND BEGINS TO INTERACT 
WITH THE BAROCLINIC ZONE BY THE END OF THE FORECAST PERIOD.  
   D. CURRENT AND FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR 
AN ABOVE AVERAGE SIZE SYSTEM.
FORECAST TEAM: WINGEART/PIVIN/LAM/KUMAGA//
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