WDPN32 PGTW 210300
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM (TS) 12W (KROVANH)/
WARNING NR 20//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 210000Z3 TO 260000Z8 AUG 2003.
   A. TROPICAL STORM (TS) 12W (KROVANH), LOCATED APPROXIMATELY
535 NM EAST-NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD
AT 10 KNOTS OVER THE PAST 06 HOURS. THE WARNING POSITION IS BASED
ON 202330Z0 MULTISPECTRAL SATELLITE IMAGERY. THE WARNING INTENSITY
IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 55 AND 65 KNOTS.
TS 12W HAS DEVELOPED A BANDING EYE IN THE PAST 6 HOURS WITH DEEP
CYCLING CONVECTION OCCURRING PREDOMINANTLY IN THE SOUTHERN SECTORS
OF THE CIRCULATION.
   B. TS 12W IS FORECAST TO TRACK WESTWARD UNDER THE INFLUENCE OF
THE MID-LEVEL STEERING RIDGE NORTH OF THE SYSTEM AND THEN TRANSITION
TO A MORE POLEWARD TRACK AS IT TRANSITS THE WESTERN EDGE OF THE
MID-LEVEL STEERING RIDGE TO THE NORTHEAST. AVAILABLE DYNAMIC AIDS
CONSISTING OF NOGAPS, NCEP GFS, AFWA, COAMPS, JTYM, EGGR, GFDN AND
JGSM ARE IN GOOD AGREEMENT WITH THE TRACK. JGSM DOES NOT BECOME AN
OUTLIER UNTIL LATER IN THE FORECAST PERIOD WHERE IT MAINTAINS A
WESTERLY TRACK SOUTH OF HONG KONG WHILE ALL OF THE OTHER AIDS
TRANSITION TO A MORE POLEWARD SOLUTION.
   C. TS 12W IS EXPECTED TO CONTINUE TO INTENSIFY AT A CLIMATOLOGICAL
RATE UNTIL IT SKIRTS THE NORTHERN COASTLINE OF LUZON, PHILIPPINES
WHERE INTERACTION WITH LAND TO THE SOUTH WILL INHIBIT THE INFLOW OF
MOIST AIR IN THE LOWER LEVELS AND CAUSE TS 12W TO WEAKEN SOMEWHAT. 
AFTER TS 12W MOVES NORTHWESTWARD AWAY FROM LUZON INTO THE SOUTH CHINA
SEA, IT IS EXPECTED TO MAINTAIN INTENSITY OR WEAKEN SLIGHTLY AS IT
MOVES TOWARDS A MORE MARGINAL ENVIRONMENT OF THE SOUTHEAST QUADRANT
OF AN UPPER LEVEL CYCLONE ANCHORED OVER MAINLAND CHINA.
   D. FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE
SIZED SYSTEM.
   E. THE EXTENDED FORECAST CALLS FOR TS 12W TO MAKE LANDFALL TO THE
NORTH AND EAST OF HONG KONG, CHINA AT APPROXIMATELY THE 84 HOUR TAU
AND WEAKEN RAPIDLY AS IT MOVES INLAND.
3. FORECAST TEAM: GRUBER/HEATH/BAK/COOK/EDBERG//