WDPN32 PGTW 050300
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W WARNING NR 21//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 050000Z TO 080000Z AUG 2005.
   A. TYPHOON (TY) 09W (MATSA), LOCATED APPROXIMATELY 105 NM EAST-
NORTHEAST OF TAIPEI, TAIWAN, HAS TRACKED NORTHWESTWARD AT 04 KNOTS
OVER THE PAST SIX HOURS.
   B. DURING THE NEXT 72 HOURS, TY 09W IS FORECAST TO TRACK NORTH-
WESTWARD UNDER THE INFLUENCE OF A STEERING RIDGE SITUATED EAST OF
JAPAN. A STATIONARY MAJOR SHORTWAVE TROUGH REMAINS WEST OF TY 09W,
HOWEVER IT IS FILLING AND IS PROJECTED TO MOVE NORTHEASTWARD WITHIN
THE NEXT 48 HOURS. AS A RIDGE AXIS REMAINS OVER KOREA, THIS STEERING
FLOW WILL KEEP TY 09W OVER LAND AFTER TAU 24. IT IS POSSIBLE A SUB-
TROPICAL LOW WILL EMERGE OVER THE YELLOW SEA AFTER THE FORECAST
PERIOD, HOWEVER IT WILL HAVE BAROCLINIC CHARACTERISTICS. THE AVAIL-
ABLE DYNAMIC AIDS CONSISTING OF COAMPS, EGRR, GFDN, GFS, JGSM, JTYM,
NOGAPS, TCLAPS, AND WBAR ARE IN FAIR AGREEMENT THROUGH TAU 36 WITH
THE EXCEPTION OF JTYM AND EGRR. BOTH OF THESE MODELS DEPICT A MORE
WESTWARD SOLUTION. THIS FORECAST IS BASED ON A CONSENSUS OF ALL
AVAILABLE DYNAMIC AIDS.
   C. A TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) CELL SOUTH OF JAPAN
IS CURRENTLY ENHANCING THE EASTWARD OUTFLOW CHANNEL. THIS TUTT HAS
ALLOWED TY 09W TO MAINTAIN A RELATIVELY CONSTANT INTENSITY. HOWEVER,
AS THE SYSTEM MOVES CLOSER TO CHINA, A DISRUPTION IN THE SOUTHWESTER-
LY AND WESTERLY SURFACE INFLOW WILL BEGIN TO WEAKEN TY 09W. ONCE THE
SYSTEM IS OVER LAND, IT WILL BEGIN TO DECOUPLE AND START DISSIPATION.
FULL DISSIPATION SHOULD OCCUR BY TAU 72.
   D. CURRENT WIND RADII ARE BASED ON 042100Z SURFACE OBSERVATIONS.
FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE-SIZED
SYSTEM INTERACTING WITH LAND.
3. FORECAST TEAM: ALPHA//
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