WDPN31 PGTW 230300
MSGID/GENADMIN/NAVPACMETOCCEN PEARL//JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON (TY) 12W (FENGSHEN) WARNING 
NR 36//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 230000Z5 TO 260000Z8 JUL 02.
   A. TYPHOON (TY) 12W (FENGSHEN), LOCATED APPROXIMATELY 340 NM EAST 
OF IWO JIMA, HAS TRACKED WEST-NORTHWESTWARD AT 14 KNOTS OVER THE 
PAST SIX HOURS. THE WARNING POSITION IS BASED ON 222330Z2 
MULTISPECTRAL SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON 
SATELLITE CURRENT INTENSITY ESTIMATES OF 115 KNOTS. 222025Z3 AND 
222230Z1 SPECIAL SENSOR MICROWAVE IMAGER (SSM/I) PASSES INDICATE A 
WEAKENING SYSTEM WITH DECREASED CONVECTION IN THE SOUTHERN 
SEMICIRCLE AND AN ERODING EYEWALL.
   B. THE MID-LEVEL SUBTROPICAL RIDGE NORTH OF THE SYSTEM IS 
EXPECTED TO CONTINUE TO PROPAGATE EASTWARD AS A SHORTWAVE TROUGH 
DEEPENS OVER MAINLAND CHINA TO THE NORTHWEST OF THE SYSTEM. TY 12W 
IS EXPECTED TO TRACK WEST-NORTHWESTWARD ON THE EQUATORWARD SIDE OF 
THE SUBTROPICAL RIDGE TOWARD THE SHORTWAVE TROUGH OVER MAINLAND 
CHINA THROUGHOUT THE FORECAST PERIOD. A RIDGE BUILDING TO THE NORTH 
OF TY 12W DURING THE MID-PERIOD WILL ADD A MORE WESTERLY COMPONENT 
TO THE TRACK. THE AVAILABLE DYNAMIC AIDS CONSISTING OF NCEP AVIATION 
(AVN), GFDN, NOGAPS (NGPS), AFWA MM5, COAMPS, UKMET OFFICE GLOBAL 
(EGRR), AND THE JAPANESE GLOBAL (JGSM) AND TYPHOON (JTYM) MODELS ARE 
IN GOOD AGREEMENT. OUR FORECAST IS BASED ON A BLEND OF ALL AVAILABLE 
DYNAMIC AIDS.
   C. TY 12W HAS BEGUN TO WEAKEN AND IS FORECAST TO CONTINUE TO 
WEAKEN THROUGHOUT THE FORECAST PERIOD. THE SYSTEM IS EXPECTED TO 
ENCOUNTER INCREASING VERTICAL WIND SHEAR FROM UPPER LEVEL 
SOUTHWESTERLIES BY THE LATE PERIOD.    
   D. INITIAL WIND RADII IS BASED ON A RECENT QUIKSCAT PASS. 
FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE SYSTEM. 
3. FORECAST TEAM: BRYANT/JACOBS/SHERRY/NUTONGLA//



NNNN