WDPN31 PGTW 261500 
1. FOR METEOROLOGISTS.
PROGNOSTIC REASONING FOR 261200Z8 SEP 02 TO 281200Z3 SEP 02.
   A. TROPICAL STORM (TS) 24W (MEKKHALA), LOCATED OVER THE GULF OF 
TONKIN, HAS TRACKED NORTH-NORTHWEST AT 05 KNOTS DURING THE PAST 6 
HOURS. THE WARNING POSITION IS BASED ON 261130Z3 ENHANCED INFRARED 
SATELLITE IMAGERY AND SYNOPTIC DATA. THE WARNING INTENSITY IS BASED 
ON SATELLITE CURRENT INTENSITY ESTIMATES OF 45 KNOTS AND A WEAKENING 
TREND.  
   B. A MID-LEVEL RIDGE TO THE EAST OF TS 24W IS INFLUENCING A 
POLEWARD MOTION. THE STEERING RIDGE IS EXPECTED TO PERSIST, HOWEVER, 
A SHORT WAVE RIDGE BEHIND THE PASSING MID-LAT TROUGH IS EXPECTED TO  
WEAKEN THE STEERING CONDITIONS BY THE 24 HOUR POINT. TS 24W IS 
EXPECTED TO MAKE LANDFALL IN SOUTHERN CHINA AND TRACK BACK TOWARD 
THE COASTLINE OR BECOME QUASI-STATIONARY. NOGAPS, JMA GLOBAL AND 
TYPHOON AND GFDN SUPPORT THIS SOLUTION.  NCEP AVN IS FASTER AND 
COUPLES TS 242 WITH THE UPPER LEVEL TROUGH. OUR FORECAST IS BASED ON 
PERSISTENCE, A BLEND OF THE AVAILABLE MODELS, BUT DISCOUNTS THE AVN 
SOLUTION.
   C. AN UPPER LEVEL HIGH SITUATED OVER BANGLADESH EXTENDS OVER THE 
GULF OF TONKIN. VERTICAL WIND SHEAR ASSOCIATED WITH THE SOUTHEAST 
QUADRANT IS FORECAST TO WEAKEN TS 24W AS IT TRACKS POLEWARD AND 
MAKES LANDFALL IN CHINA.
   D. WIND RADII ANALYSIS IS BASED ON SYNOPTIC DATA.
FORECAST TEAM: SMITH/KENDALL/DANIEL/RONSSE/SCHAEFER/COOK//

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