WDPN31 PGTW 090300
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 090000Z9 TO 120000Z3 JUL 02.
   A. TYPHOON (TY) 08W (CHATAAN), LOCATED APPROXIMATELY 380 NM 
SOUTH OF SHIKOKU ISLAND, HAS TRACKED NORTHWARD AT 12 KNOTS DURING 
THE PAST 6 HOURS. THE WARNING POSITION IS BASED ON 082330Z6 VISIBLE 
AND ENHANCED INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS 
BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 115 AND 127 KNOTS. 
ANIMATED INFRARED IMAGERY INDICATES THAT THE DEEP CONVECTION IN THE 
WESTERN SEMICIRCLE HAS WEAKENED DURING THE PAST 12 HOURS. A 082156Z2 
SSM/I PASS PROVIDES SUPPORTING EVIDENCE OF WEAKENING IN THE WESTERN 
SEMICIRCLE.     
   B. TY 08W IS CURRENTLY TRACKING ALONG THE WESTERN PERIPHERY OF A 
POLEWARD ORIENTED MID-LEVEL RIDGE CENTERED NEAR 30N3 140E5. A 
SHORTWAVE TROUGH TRACKING INTO THE SEA OF JAPAN IS FORECASTED TO 
AFFECT THE STEERING ENVIRONMENT AND TURN TY 08W NORTHEASTWARD IN 24 
HOURS. THE AVAILABLE DYNAMIC AIDS CONSISTING OF AVN, NOGAPS, COAMPS, 
THE UK-MET GLOBAL (EGRR), AFWA MESOSCALE (MM5), AND THE JAPANESE 
GLOBAL (JGSM) AND TYPHOON (JTYM) MODELS ARE IN GOOD AGREEMENT. OUR 
FORECAST IS BASED ON A BLEND OF ALL THE DYNAMIC AIDS.
   C. TY 08W IS EXPECTED TO WEAKEN IN THE NEXT 24 HOURS 
AS SEA SURFACE TEMPERATURES DROP. AFTERWARDS, TY 08W IS FORECAST TO 
WEAKEN MORE RAPIDLY AS IT INTERACTS WITH MID-LAT WESTERLIES AND 
TERRAIN.
   D. WIND RADII ANALYSIS BASED IS BASED ON SYNOPTIC DATA. FORECAST 
WIND RADII BASED ON CLIMATOLOGY FOR AN AVERAGE SIZE SYSTEM. 
3. FORECAST TEAM: SMITH/KENDALL/WARREN/EDBERG/SCHAEFER//

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