WDPN32 PGTW 120300
MSGID/GENADMIN/NAVPACMETOCCEN PEARL//JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 10W (HALONG) WARNING NR 21//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 120000Z3 TO 150000Z6 JUL 02.
   A. TYPHOON (TY) 10W (HALONG), LOCATED APPROXIMATELY 640 NM SOUTH-
SOUTHWEST OF IWO JIMA, HAS TRACKED WEST-NORTHWESTWARD AT 10 KNOTS 
DURING THE PAST SIX HOURS. THE WARNING POSITION IS BASED ON 112330Z6 
ENHANCED INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED 
ON SATELLITE CURRENT INTENSITY ESTIMATES OF 90 AND 102 KNOTS. 
ANIMATED VISIBLE IMAGERY INDICATES THAT AN EYE HAS DEVELOPED OVER 
THE PAST 3 HOURS. 
   B. THE SUBTROPICAL RIDGE LOCATED NORTHEAST OF TY 10W IS EXPECTED 
TO REMAIN QUASI-STATIONARY OVER THE NEXT 36 TO 48 HOURS AND THEN 
WEAKEN AS AN UPPER LEVEL TROUGH TRACKS EASTWARD OVER MONGOLIA TOWARD 
THE EAST CHINA SEA. TY 10W IS EXPECTED TO TRACK NORTHWESTWARD OVER 
THE NEXT 48 HOURS AND THEN NORTHWARD TOWARD THE WEAKNESS IN THE 
SUBTROPICAL RIDGE. THE AVAILABLE DYNAMIC AIDS CONSIST OF THE NCEP 
AVIATION (AVN), NOGAPS, UKMET GLOBAL, GFDN, COAMPS, AND JAPANESE 
GLOBAL (JGSM) AND TYPHOON (JTYM) MODELS. GFDN FIELDS INDICATE THAT 
THE SYSTEM WILL INTERACT WITH A WEAKNESS EAST OF LUZON. SYNOPTIC 
DATA DOES NOT INDICATE THAT A LOW LEVEL CIRCULATION EXISTS, 
THEREFORE THIS SCENARIO IS UNLIKELY. EGRR SUGGESTS A SHARPER 
RECURVATURE THAN THE OTHER DYNAMIC AIDS. OUR FORECAST IS BASED ON A 
BLEND OF ALL AVAILABLE DYNAMIC AIDS.
   C. TY 10W IS EXPECTED TO DEVELOP SLOWLY OVER THE NEXT 36 TO 48 
HOURS WHILE NORTHEASTERLIES CONTINUE TO AFFECT THE SYSTEM OUTFLOW. 
TY 10W IS EXPECTED TO WEAKEN SLOWLY BY 72 HOURS AS IT TRACKS 
NORTHWARD IN A LESS FAVORABLE UPPER LEVEL ENVIRONMENT. 
   D. CURRENT WIND RADII ARE BASED ON A RECENT QUICKSCAT PASS AND 
SYNOPTIC DATA. FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN 
AVERAGE-SIZED SYSTEM. 
3. FORECAST TEAM: WINGEART/LAM/KUMAGA/STATEN//
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