WDPN31 PGTW 200300
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM (TS) 20W (KETSANA)/
WARNING NR 06//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 200000Z2 TO 250000Z7 OCT 2003.
   A. TROPICAL STORM (TS) 20W (KETSANA), LOCATED APPROXIMATELY
800 NM SOUTHWEST OF IWO JIMA, CONTINUES TO SLOWLY DRIFT NORTH-
EASTWARD OVER THE PAST 06 HOURS. THE WARNING POSITION IS BASED 
ON 192330Z8 MULTISPECTRAL SATELLITE IMAGERY. THE WARNING 
INTENSITY IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 
45 AND 55 KNOTS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY 
REVEALS INCREASING DEEP CONVECTION WITH A STRONG BANDING FEATURE
TO THE SOUTH OF A WELL ORGANIZED LOW LEVEL CIRCULATION CENTER 
(LLCC). 
   B. TS 20W IS DRIFTING SLOWLY NORTHEASTWARD ALONG THE 
WESTERN PERIPHERY A MID-LEVEL STEERING RIDGE LOCATED TO THE 
NORTHEAST OF THE SYSTEM. TS 20W IS EXPECTED TO CONTINUE TO SLOWLY 
DRIFT IN A PREDOMINANTLY NORTHEASTWARD DIRECTION FOR THE NEXT 12 
TO 24 HOURS. AFTER TAU 24, TS 20W WILL THEN HAVE A MORE DEFINITIVE 
NORTHEASTWARD TRACK AS THE STEERING RIDGE BUILDS IN FROM THE EAST 
AND THE SYSTEM IS FULLY INFLUENCED BY THIS RIDGE. THE AVAILABLE 
DYNAMIC AIDS CONSISTING OF THE UKMET (EGRR), JGSM, JTYM, AND AVN 
(GFS) MODELS ARE IN GOOD AGREEMENT. INITIALLY THE NOGAPS MODEL 
HOLDS TS 20W QUASI-STATIONARY AND THEN HAS THE SYSTEM DRIFTING
SOUTHWESTWARD FOR THE REMAINDER OF THE FORECAST PERIOD DUE TO 
INTERACTION WITH A WEAK CIRCULATION TO THE EAST OF TS 20W. THIS 
FORECAST IS BASED ON A CONSENSUS OF AVAILABLE MODELS WITH EXCEPTION 
OF THE NOGAPS MODEL.
   C. TS 20W IS EXPECTED TO INTENSIFY AT A NEAR CLIMATOLOGICAL RATE 
THROUGH TAU 72. AFTER THIS TIME, TS 20W IS EXPECTED TO INTENSIFY 
AT A LESS THAN CLIMATOLOGICAL RATE AND THEN WEAKEN DUE TO BEING 
STEERED INTO AN AREA OF HIGHER VERTICAL WIND SHEAR AND SLIGHTLY 
COOLER SEA SURFACE TEMPERATURES. 
   D. CURRENT WIND RADII IS BASED ON A RECENT QUIKSCAT PASS AND 
FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE SIZED 
SYSTEM.
3. FORECAST TEAM: MOHAMMED/JACOBS/DENSON/HERNANDEZ/NUTONGLA/SCHULTZ//

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