WDPN31 PGTW 290300
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON (TY) 17W (KOPPU)/
WARNING NR 19//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 290000Z1 SEP TO 020000Z2 OCT 2003.
   A. TYPHOON (TY) 17W (KOPPU), LOCATED APPROXIMATELY 160 NM NORTH OF
IWO JIMA, HAS TRACKED NORTH-NORTHEASTWARD AT 09 KNOTS OVER THE PAST
06 HOURS. THE WARNING POSITION IS BASED ON 282330Z8 MULTISPECTRAL
SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON SATELLITE CURRENT
INTENSITY ESTIMATES OF 65 AND 90 KNOTS. ANIMATED WATER VAPOR SATELLITE
IMAGERY INDICATES THAT THE SYSTEM IS BEGINNING TO ENTRAIN DRY AIR FROM
THE WEST.
   B. TY 17W IS FORECASTED TO CONTINUE TO TRACK NORTHEASTWARD ALONG THE
WESTERN PERIPHERY OF THE MID-LEVEL STEERING RIDGE ANCHORED TO THE EAST.
A SHORTWAVE TROUGH LOCATED OVER THE SEA OF JAPAN IS EXPECTED TO DEEPEN AND
INTERACT WITH TY 17W IN 12 TO 24 HOURS. THIS WILL CAUSE TY 17W TO
ACCELERATE NORTHEASTWARDS, ENTER THE BAROCLINIC ZONE, AND TRANSITION TO
AN EXTRATROPICAL LOW. THE AVAILABLE DYNAMIC AIDS, CONSISTING OF NOGAPS,
COAMPS, UKMET EGRR, GFDN, JGSM, AND JTYM ARE IN FAIR AGREEMENT WITH THIS
FORECAST SCENARIO. THIS FORECAST IS BASED ON A CONSENSUS OF ALL AVAILABLE
DYNAMIC AIDS.
   C. TY 17W HAS REACHED PEAK INTENSITY AND IS EXPECTED TO WEAKEN
SIGNIFICANTLY AFTER 12 TO 24 HOURS AS IT BEGINS TO ENCOUNTER UPPER LEVEL
WESTERLY FLOW AND UNDERGOES TRANSITION TO AN EXTRATROPICAL SYSTEM.
   D. CURRENT WIND RADII ARE BASED ON A 282001Z3 QUIKSCAT PASS AND
FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN ABOVE AVERAGE SIZED
SYSTEM.
 3. FORECAST TEAM: WINGEART/ALLEN/MENEBROKER//

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