WDPN31 PGTW 180300 
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (DIANMU)
/WARNING NR 21//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 180000Z9 TO 230000Z5 JUN 2004.
   A.  TYPHOON 09W (DIANMU) LOCATED APPROXIMATELY 520 NM SOUTH-
SOUTHEAST OF OKINAWA, JAPAN, HAS TRACKED NORTHWEST AT 06 KNOTS 
OVER THE PAST 06 HOURS. THE WARNING POSITION IS BASED ON 
172330Z6 MULTISPECTRAL SATELLITE IMAGERY. THE WARNING 
INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 
115 AND 127 KNOTS. 
   B.  TY 09W IS FORECAST TO CONTINUE TRACKING POLEWARD 
THROUGHOUT THE FORECAST PERIOD. A PERIPHERAL RIDGE TO THE
NORTHWEST IS EXPECTED TO MIGRATE TOWARD THE SOUTHWEST WITH THE 
APPROACH OF A SHORTWAVE TROUGH FROM THE WEST. TY 09W IS FORECAST 
TO CONTINUE TRACKING ALONG A MORE POLEWARD TRACK ALONG THE 
WESTERN PERIPHERY OF THE BUILDING MID LEVEL STEERING RIDGE 
ANCHORED TO THE EAST OF TY 09W. THE AVAILABLE DYNAMIC AIDS, 
CONSISTING OF NOGAPS, GFDN, UKMET, JGSM, AND NCEP GFS, ARE IN 
FAIR AGREEMENT WITH THE OVERALL SCENARIO THROUGH TAU 72. 
AFTER THIS TIME, THE GFDN AND UKMET EGRR MODELS SHOW DIRECT 
CYCLONE INTERACTION BETWEEN TY 09W AND AN UPPER LEVEL LOW OVER 
THE YELLOW SEA. THIS FORECAST IS BASED ON PERSISTENCE, CONTINUITY 
AND A CONSENSUS OF ALL AVAILABLE DYNAMIC AIDS.
   C. THE RADIAL OUTFLOW OF TY 09W HAS DIMINISHED TO THE NORTH 
DUE TO THE PRESENCE OF THE MIGRATORY RIDGE BUT THE EQUATORWARD 
OUTFLOW HAS BEEN MAINTAINED. POLEWARD MOVEMENT INTO THE CONVERGENT 
QUADRANT OF THE UPPER LEVEL RIDGE WILL FURTHER SUPPRESS ITS POLEWARD 
OUTFLOW. HOWEVER, RECENT MICROWAVE IMAGERY REVEALS CONCENTRIC EYE 
WALLS INDICATIVE OF INTENSIFICATION, THUS THE SYSTEM SHOULD CONTINUE 
TO WEAKEN BUT AT A SLOWER RATE.
   D. CURRENT WIND RADII ARE BASED ON A RECENT QUIKSCAT PASS.
FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE SIZED
SYSTEM. 
   E. THE EXTENDED FORECAST HAS TY 09W CONTINUING POLEWARD 
OVER KYUSHU AND INTO THE SEA OF JAPAN. AT THIS TIME THE SYSTEM IS 
EXPECTED TO EXPERIENCE INCREASING VERTICAL WIND SHEAR AND WEAKEN 
SIGNIFICANTLY AS IT INTERACTS WITH LAND AND ENTERS INTO THE 
COLDER WATERS OF THE SEA OF JAPAN. 
3. FORECAST TEAM: ARENDS/KLINZMANN/HEILER//