WDPN31 PGTW 221500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 04W (FOUR) WARNING 
NR 03//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 04W (FOUR), LOCATED APPROXIMATELY 382 NM 
SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 
08 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE 
IMAGERY (IR) SHOWS WEAKENING CONVECTION ALONG THE NORTHERN PERIPHERY 
OF THE LOW LEVEL CIRCULATION CENTER (LLCC) WHICH HAS STARTED TO 
BECOME LESS DEFINED. THE INITIAL POSITION IS BASED UPON THE IR LOOP 
AND RADAR ANIMATION FROM CEBU STATION, PHILIPPINES, WITH LOW 
CONFIDENCE AS THE LLCC HAS STARTED TO OPEN UP. THE INITIAL INTENSITY 
HAS BEEN DECREASED TO 25 KNOTS BASED UPON THE DECREASING STRUCTURE 
SEEN IN THE IR LOOP ALONG WITH DVORAK INTENSITY ESTIMATES OF 25 
KNOTS FROM PGTW AND KNES. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM 
IS SOUTH OF A RIDGE AXIS IN AN AREA OF LOW TO MODERATE (10-15 KNOT) 
VERTICAL WIND SHEAR AND FAIR POLEWARD OUTFLOW. TD 04W IS CURRENTLY 
TRACKING ALONG WITH THE LOW-LEVEL FLOW TOWARDS THE SOUTH CENTRAL 
PHILIPPINE ISLANDS.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.
   B. TD 04W IS EXPECTED TO SLOWLY TRACK WESTWARD WITH THE LOW-LEVEL 
FLOW ACROSS THE CENTRAL PHILIPPINE ISLANDS, WEAKENING DUE TO THE 
FRICTIONAL EFFECTS OF THE ISLANDS BEFORE DISSIPATING IN THE SULU SEA 
AS THE SYSTEM BECOMES EXPOSED TO THE RELATIVELY DRIER NORTHEAST 
MONSOON FLOW. THE AVAILABLE LIMITED NUMERIC GUIDANCE IS IN AGREEMENT 
WITH A GENERAL WESTWARD TRACK BUT IS SLIGHTLY SPREAD DUE TO THE 
WEAKENED STATE OF THE VORTEX. THEREFORE, LOW CONFIDENCE REMAINS IN 
THE JTWC FORECAST TRACK.//
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