WDPN31 PGTW 091500
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 23W WARNING NR 10//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 091200Z TO 141200Z NOV 2005.
   A. TROPICAL STORM (TS) 23W, LOCATED APPROXIMATELY 405 NM EAST
OF MANILA, PHILIPPINES HAS TRACKED WEST-NORTHWESTWARD AT 20 KNOTS
OVER THE PAST SIX HOURS.
   B. TS 23W HAS ACCELERATED AS IT TRACKS ALONG THE SOUTHERN PERIPH-
ERY OF A STRENGTHENING LOW TO MID LEVEL STEERING RIDGE CENTERED OVER
THE LUZON STRAIT. THE SYSTEM WILL DECELERATE IN THE NEAR TERM AND
BEGIN A POLEWARD TURN AFTER TRACKING ACROSS LUZON AS THE STEERING
RIDGE WEAKENS AND RECEDES TO THE EAST IN RESPONSE TO A TRANSITING
BAROCLINIC SYSTEM. THE DYNAMIC AIDS CONSISTING OF NCEP GFS, EGRR,
WBAR, COAMPS, NOGAPS, GFDN AND AFWA MM5 ARE IN FAIR AGREEMENT WITH
THIS SCENARIO THROUGH TAU 72. DISPARITY BETWEEN THE AIDS ARISES FROM
VARYING AMOUNTS OF WEAKENING AND ORIENTATION OF THE STEERING RIDGE.
THIS FORECAST IS BASED ON A CONSENSUS OF ALL AVAILABLE DYNAMIC AIDS.
   C. TS 23W HAS RAPIDLY INTENSIFIED OVER THE LAST 12 HOURS AS VERT-
ICAL WIND SHEAR HAS WEAKENED AND A GOOD RADIAL OUTFLOW PATTERN HAS
DEVELOPED. THIS TREND WILL ABATE IN THE NEAR TERM AS LANDFALL IS MADE
IN LUZON. AFTER EMERGING IN THE SOUTH CHINA SEA NEAR TAU 36, THE
SYSTEM WILL STRENGTHEN THROUGH TAU 72.
   D. CURRENT WIND RADII ARE BASED ON SURFACE OBSERVATIONS AND FORE-
CAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE SIZED SYSTEM.
   E. IN THE EXTENDED PERIOD, THE MID LEVEL STEERING RIDGE WILL CON-
TINUE TO RECEDE TO THE EAST CAUSING TS 23W TO BECOME ORIENTED ON ITS
WESTERN PERIPHERY. THIS ORIENTATION WILL CAUSE A CONTINUED POLEWARD
TURN AND LANDFALL INTO SOUTHERN CHINA IS EXPECTED BY TAU 120. THE
SYSTEM WILL ALSO WEAKEN IN THE EXTENDED PERIOD IN RESPONSE TO GREATER
VERTICAL WIND SHEAR AND INTERACTION WITH LAND.
3. FORECAST TEAM: DELTA//
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