WDPN31 PGTW 291500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 20W (NESAT) WARNING NR 25//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
   A. TYPHOON 20W (NESAT), LOCATED APPROXIMATELY 230 NM EAST OF 
HANOI, VIETNAM, HAS TRACKED WESTWARD AT 11 KNOTS OVER THE PAST SIX 
HOURS. ANIMATED INFRARED SATELLITE IMAGERY DEPICTS RAPIDLY WEAKENING 
DEEP CONVECTION, DUE TO LAND INTERACTION, SURROUNDING A RAGGED 10 NM 
EYE. A 291100Z SSMIS IMAGE, HOWEVER, CONTINUES TO INDICATE A WELL-
DEFINED, BROAD LOW-LEVEL CIRCULATION CENTER (LLCC) WITH MULTIPLE 
CONVECTIVE BANDS WRAPPING INTO THE CENTER. SURFACE OBSERVATIONS FROM 
ZJSY, ABOUT 115 NM SOUTH-SOUTHWEST OF THE CENTER, INDICATE SURFACE 
WINDS SUSTAINED AT 25-30 KNOTS WITH GUSTS TO 40-45 KNOTS. ANIMATED 
WATER VAPOR IMAGERY INDICATES GOOD RADIAL OUTFLOW. THE CURRENT 
POSITION IS BASED ON THE RECENT PGTW POSITION FIX AND THE 291100Z 
SSMIS IMAGE. THE CURRENT INTENSITY IS BASED ON DVORAK INTENSITY 
ESTIMATES OF 65 KNOTS FROM PGTW AND KNES. 
3. FORECAST REASONING.
   A. THE FORECAST PHILOSOPHY HAS NOT CHANGED.
   B. TY 20W IS TRACKING WESTWARD UNDER THE STEERING INFLUENCE OF 
THE SUBTROPICAL RIDGE POSITIONED OVER SOUTHEAST CHINA AND IS 
FORECAST TO TRACK INTO NORTHERN VIETNAM AFTER TAU 18. THE SYSTEM IS 
EXPECTED TO DISSIPATE OVER LAND BY TAU 36. DYNAMIC MODEL GUIDANCE IS 
IN TIGHT AGREEMENT AND SUPPORTS THIS FORECAST.//
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