WDPN31 PGTW 181500
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 27W WARNING NR 
07//
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 181200Z2 TO 211200Z6 OCT 02.
    A. TROPICAL DEPRESSION (TD) 27W, LOCATED APPROXIMATELY 390 NM 
EAST OF SAIPAN, HAS TRACKED WESTWARD AT 09 KNOTS OVER THE PAST SIX 
HOURS. THE WARNING POSITION IS BASED ON 181130Z4 ENHANCED INFRARED 
SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON SATELLITE 
CURRENT INTENSITY ESTIMATES OF 30 AND 35 KNOTS. ANIMATED ENHANCED 
INFRARED SATELLITE IMAGERY INDICATES THAT THE CENTRAL CONVECTION HAS 
WEAKENED OVER THE PAST SIX HOURS.
    B. TD 27W REMAINS UNDER THE STEERING INFLUENCE OF A WEAK LOW-
LEVEL SUBTROPICAL RIDGE NORTHEAST OF THE SYSTEM. THE SUBTROPICAL 
RIDGE IS EXPECTED TO SLOWLY BUILD AND PROPAGATE EASTWARD THROUGH THE 
PERIOD. A LONGWAVE TROUGH LOCATED OVER EASTERN CHINA IS EXPECTED TO 
PROPAGATE EASTWARD THROUGH 72 HOURS, WEAKENING THE SUBTROPICAL 
RIDGE. 
TD 27W IS EXPECTED TO TRACK WESTWARD THROUGH 24 TO 36 HOURS ALONG 
THE BUILDING RIDGE AND THEN TURN POLEWARD TOWARD THE WEAKNESS IN THE 
SUBTROPICAL RIDGE BY 72 HOURS. THE AVAILABLE DYNAMIC AIDS, 
CONSISTING OF NOGAPS, GFDN, AFWA MM5, COAMPS, NCEP AVIATION (AVN), 
AND UKMET GLOBAL (EGRR), ARE IN FAIR AGREEMENT WITH THE EXCEPTION OF 
AFWA MM5. MM5 KEEPS THE SYSTEM WEAK THROUGH 72 HOURS, TRACKING THE 
SYSTEM SOUTHWEST BY 72 HOURS. OUR FORECAST IS BASED ON A BLEND OF 
ALL AVAILABLE DYNAMIC AIDS WITH LESS EMPHASIS ON MM5.
    C. TD 27W IS EXPECTED TO INTENSIFY AT A LESS THAN CLIMATOLOGICAL 
RATE THROUGH THE FORECAST PERIOD AS IT TRACKS IN A MARGINAL UPPER 
LEVEL ENVIRONMENT.
    D. FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR A SMALL-
SIZED SYSTEM.
3. FORECAST TEAM: WINGEART/LAM/KUMAGA/STATEN//
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