WDPN32 PGTW 021500
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W WARNING NR 11//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 021200Z TO 071200Z AUG 2005.
   A. TYPHOON (TY) 09W (MATSA), LOCATED APPROXIMATELY 435 NM SOUTH 
OF OKINAWA, HAS TRACKED NORTHWESTWARD AT 12 KNOTS OVER THE PAST SIX
HOURS. CURRENT ANIMATED ENHANCED INFRARED IMAGERY DEPICTS SUPRESSED
OUTFLOW AND A LACK OF DEEP CONVECTION IN THE NORTHWESTERN QUADRANT
OF THE STORM. HOWEVER, EQUATORWARD OUTFLOW REMAINS WELL ESTABLISHED
AND DEEP CONVECTION HAS DEVELOPED IN THE REMAINING THREE QUADRANTS.
   B. THE STORM IS CURRENTLY SITUATED ON THE WESTERN PERIPHERY OF A
N/S ORIENTED STEERING RIDGE. A TRANSIENT MID-LEVEL RIDGE LOCATED NEAR
TAIWAN IS ALSO PROVIDING SOME WESTWARD STEERING INFLUENCE TO TY 09W.
THE RESULTANT MOTION EARLY IN THE FORECAST PERIOD WILL REMAIN TOWARD
THE NORTHWEST. HOWEVER, AN ADVANCING MIDLATITUDE TROUGH OVER EASTERN
CHINA WILL WEAKEN THE MID-LEVEL RIDGE TO THE NORTHWEST OF THE SYSTEM
AND ALLOW TY 09W TO TURN MORE POLEWARD BETWEEN TAUS 24 AND 72.
MOREOVER, THE SYSTEM WILL ENTER A WEAKER STEERING ENVIRONMENT AND
SLOW  DURING THIS TIME FRAME AS THE INFLUENCE OF THE INTIAL STEERING
RIDGE WANES AND THE PRIMARY STEERING MECHANISM TRANSITIONS TO AN EX-
TENSION OF THE SUBTROPICAL RIDGE NORTH OF TY 09W. THE AVAILABLE
OBJECTIVE AIDS CONSISTING OF NOGAPS, EGRR, GFDN, NCEP GFS, COAMPS,
JGSM, JTYM, TCLAPS AND WBAR ARE IN FAIR AGREEMENT WITH THIS SCENARIO
WITH THE EXCEPTION OF THE MM5 WHICH IS AN EASTWARD OUTLIER. THIS
FORECAST IS BASED ON A CONSENSUS OF ALL AVAILABLE DYNAMIC AIDS.
   C. TY 09W IS FORECAST TO INTENSIFY THROUGH THE MIDDLE OF THE FORE-
CAST PEROID AS SUBSIDENCE ASSOCIATED WITH THE MID-LEVEL ANTICYCLONE
LESSENS OVER THE NORTHWEST QUADRANT OF THE STORM AND OUTFLOW IMPROVES.
THE SYSTEM SHOULD REMAIN IN A LOW-SHEAR ENVIRONMENT WITH SUSTAINED
EQUATORWARD OUTFLOW.
   D. CURRENT WIND RADII ARE BASED ON A 020958Z QUIKSCAT PASS, AND
FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR A LARGE SYSTEM.
   E. TY 09W IS FORECAST TO ACCELERATE NORTHWARD AFTER TAU 96 AS AN
EXTENSION OF THE SUBTROPICAL STEERING RIDGE EAST OF THE SYSTEM
STRENGTHENS. THE STORM SHOULD REACH MAXIMUM INTENSITY BETWEEN 72 AND
96 HOURS BUT BEGIN TO WEAKEN THEREAFTER AS IT CONTINUES TO MOVE POLE-
WARD AND ENCOUNTERS INCREASINGLY DRY AIR DUE TO PROXIMITY WITH THE
ASIAN LANDMASS.
3. FORECAST TEAM: CHARLIE//
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