WDPN31 PGTW 261500
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 24W WARNING NR 04//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 261200Z NOV TO 011200Z DEC 2006.
   A. TROPICAL STORM (TS) 24W (DURIAN), LOCATED APPROXIMATELY 220
NM EAST OF YAP, HAS TRACKED WEST-NORTHWESTWARD AT 11 KNOTS OVER
THE PAST SIX HOURS.
   B. TS 24W CONTINUES TO TRACK WEST-NORTHWESTWARD ALONG THE PERI-
PHERY OF A LOW- TO MID-LEVEL (850-700 MB) RIDGE ANCHORED TO THE
NORTH. TS 24W WILL TRANSITION TO A DEEPER STEERING LAYER AS IT
INTENSIFIES, AND THUS WILL COME UNDER THE INFLUENCE OF A 500 MB
RIDGE CURRENTLY ANCHORED TO THE NORTHWEST OF THE SYSTEM. THE 500 MB
ANTICYCLONE IS FORECAST TO BUILD AS IT DRIFTS SLOWLY EASTWARD DURING
THE FORECAST PERIOD, AND WILL KEEP TS 24W ON A WEST-NORTHWESTWARD
TRACK THROUGH TAU 72. THE AVAILABLE DYNAMIC AIDS ARE IN GOOD AGREE-
MENT WITH THIS SCENARIO. THE OUTLIER, UKMET EGRR, FORECASTS A VERY
DEEP AND STRONG RIDGE AND THUS DUE WESTWARD MOTION THROUGHOUT THE
FORECAST PERIOD.  
   C. DESPITE FAVORABLE OUTFLOW, DEEP CONVECTION ASSOCIATED WITH
TS 24W HAS DECREASED OVER THE PAST 12 HOURS, AND HAS ONLY RECENTLY
BEGUN TO REDEVELOP OVER THE LOW LEVEL CIRCULATION CENTER IN THE PAST
SEVERAL HOURS. CONVECTION IS FORECAST TO CONTINUE CONSOLIDATING IN AN
ENVIRONMENT OF LOW TO MODERATE VERTICAL WIND SHEAR AND VERY FAVORABLE
DIVERGENCE ALOFT. TS 24W IS FORECAST TO INTENSIFY AT A GREATER THAN
CLIMATOLOGICAL RATE THROUGH TAU 72. 
   D. CURRENT WIND RADII ARE BASED ON A 260852Z QUIKSCAT IMAGE.
FORECAST WIND RADII CRITERIA ARE BASED ON CLIMATOLOGY FOR AN AVERAGE-
SIZED SYSTEM.
   E. AN APPROACHING MID-LATITUDE TROUGH IS FORECAST TO WEAKEN THE
STEERING RIDGE OVER LUZON AFTER TAU 72; TS 24W WILL TRACK NORTHWEST-
WARD TOWARD THIS DEVELOPING WEAKNESS. TS 24W IS FORECAST TO REACH
MAXIMUM INTENSITY PRIOR TO MAKING LANDFALL IN THE PHILIPPINES, AND
WILL WEAKEN SLIGHTLY DUE TO TERRAIN INTERACTION AND DISRUPTION OF THE
LOW LEVEL INFLOW, AND DRIER AIR BECOMES INGESTED INTO THE CIRCULATION.
FORECAST TEAM: CHARLIE//
NNNN