WDPN31 PGTW 091500 
MSGID/GENADMIN/NAVPACMETOCCEN PEARL//JTWC//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION (TD) 03W WARNING 
NR 11//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 091200Z2 TO 121200Z6 MAY 01.
   A. TROPICAL DEPRESSION (TD) 03W, LOCATED APPROXIMATELY 150 NM 
SOUTH OF MANILA, HAS TRACKED NORTHWESTWARD AT 10 KNOTS OVER THE PAST 
SIX HOURS. THE WARNING POSITION IS BASED ON 091130Z4 INFRARED 
SATELLITE IMAGERY AND AVAILABLE SYNOPTIC DATA. THE WARNING INTENSITY 
IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 30 KNOTS. 
ANIMATED SATELLITE IMAGERY INDICATES THE SYSTEM MAINTAINED 
ORGANIZATION OVER THE PAST 6 HOURS. UW-CIMSS UPPER LEVEL WIND 
ANALYSIS INDICATES FAVORABLE CONDITIONS ALOFT WITH DECREASING SHEAR 
OVER THE PAST 6 HOURS. UPPER LEVEL ANALYSIS INDICATES AN ANTICYCLONE 
IS DEVELOPING OVER THE SYSTEM, PROVIDING GOOD OUTFLOW AND 
DIFFLUENCE.
   B. TD 03W IS FORECAST TO TRACK NORTHWESTWARD THROUGH THE 24 HOUR 
PERIOD UNDER THE STEERING INFLUENCE OF THE LOW TO MID-LEVEL RIDGE TO 
THE NORTHEAST. AN APPROACHING MID-LATITUDE TROUGH IS EXPECTED TO 
CREATE A WEAKNESS IN THE RIDGE ALLOWING THE SYSTEM TO TRACK 
MORE NORTHERLY AFTER 24 HOURS. THE AVAILABLE FORECAST AIDS ARE IN 
FAIR AGREEMENT. THE NAVY OPERATIONAL GLOBAL ATMOSPHERIC PREDICTION 
SYSTEM (NOGAPS) AND THE GEOPHYSICAL FLUID DYNAMICS NAVY (GFDN) MODEL 
TRACK THE SYSTEM TO THE NORTHWEST THROUGH THE FORECAST PERIOD. THE 
UK-MET OFFICE (EGRR) MODEL TRACKS THE SYSTEM NORTHWESTWARD THROUGH 
24 HOURS AND THEN MORE NORTHWARD. THE NCEP AVIATION MODEL (AVN) AND 
MEDIUM RANGE FORECAST (MRF) MODEL BOTH TRACK THE SYSTEM NORTH-
NORTHWESTWARD AND THEN NORTHWARD. THE OFFICIAL FORECAST IS BASED ON 
THE DYNAMIC AID CONSENSUS AND FAVORS THE GFDN AND EGRR TRACKS. THE 
NUMERICAL CONSENSUS CONSISTS OF THREE DYNAMIC MODELS (NOGAPS, GFDN, 
AND EGRR).      
   C. TD 03W IS EXPECTED TO SLOWLY INTENSIFY AS IT MOVES INTO A MORE 
FAVORABLE ENVIRONMENT OVER THE SOUTH CHINA SEA. 
   D. WIND RADII FOR THE 48 AND 72 HOUR FORECAST ARE BASED ON 
CLIMATOLOGY FOR AN AVERAGED SIZE STORM.
FORECAST TEAM: COX/CUTMAN//



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