WDPN31 PGTW 131500 
MSGID/GENADMIN/NAVPACMETOCCEN PEARL//JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 31W WARNING NR 
08//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 131200Z7 TO 161200Z0 DEC 01.
   A. TROPICAL DEPRESSION (TD) 31W, LOCATED NEAR THE ISLAND OF 
KOSRAE IN THE CAROLINE ISLANDS, HAS TRACKED EAST-SOUTHEASTWARD AT 09 
KNOTS DURING THE PAST SIX HOURS. THE WARNING POSITION IS BASED ON 
131130Z9 INFRARED SATELLITE IMAGERY AND A RECENT QUIKSCAT PASS 
REVEALING A COMPACT BUT WEAK CIRCULATION. THE WARNING INTENSITY IS 
BASED ON SYNOPTIC DATA AND SATELLITE CURRENT INTENSITY ESTIMATES OF 
30 KNOTS. ANIMATED WATER VAPOR IMAGERY DEPICTS A CYCLONIC 
CIRCULATION SOUTHEAST OF TD 31W IN THE SOUTHERN HEMISPHERE NEAR 
ENOUGH TO BE A FACTOR IN CROSS EQUATORIAL INTERACTION. 
   B. TD 31W APPEARS TO BE TRACKING UNDER THE STEERING INFLUENCE OF 
THE EQUATORIAL WESTERLIES. TD 31W IS FORECAST TO CONTINUE TRACKING 
EASTWARD UNDER THE PRIMARY STEERING INFLUENCE OF EQUATORWARD 
WESTERLIES BEFORE BECOMING QUASISTATIONARY NEAR THE MID-PERIOD. 
NEXT, A SLOW TURN TO THE WEST IS FORECAST AS THE LOW TO MID-LEVEL 
RIDGE BUILDS IN NORTHEAST OF THE SYSTEM. THE AVAILABLE DYNAMIC AIDS, 
CONSISTING OF THE NCEP AVIATION (AVN), NOGAPS, UK MET GLOBAL (EGRR), 
AND GFDN MODELS ARE IN POOR AGREEMENT. THE MODELS REMAIN SPLIT 
BETWEEN THE WESTERLY WIND BURST EVENT - AVN, GFDN - AND THE DOMINANT 
NORTHEASTLIES ASSOCIATED WITH THE SUBTROPICAL RIDGE. DUE TO THE 
COMPLEX INTERACTION OF TD 31W WITH THE FEATURES MENTIONED ABOVE, OUR 
FORECAST TRACK IS BASED ON PERSISTENCE AND A BLEND OF GLOBAL MODELS.
   C. TD 31W IS EXPECTED TO INTENSIFY SLOWLY AS THE SYSTEM CONTINUES 
TO STRUGGLE FOR ORGANIZATION IN THE MONSOON TROUGH WHILE IN AN 
OTHERWISE FAVORABLE ENVIRONMENT.
   D. THE SYSTEM DOES NOT MEET WIND RADII CRITERIA. 
FORECAST TEAM: SMITH/MAYER/WEAVER/TON//
BT
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