MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 21W (DUJUAN) WARNING NR 25// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 21W (DUJUAN), LOCATED APPROXIMATELY 220 NM SOUTHEAST OF TAIPEI, TAIWAN, HAS TRACKED WEST-NORTHWESTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS THE SYSTEM HAS MAINTAINED A LARGE 44-NM EYE AND CONTINUES TO HAVE HIGHLY SYMMETRIC DEEP CONVECTION WRAPPING TIGHTLY INTO THE EYE. THE INITIAL POSITION IS BASED ON THE EYE FEATURE WITH HIGH CONFIDENCE. THE INITIAL INTENSITY OF 125 KNOTS IS BASED ON DVORAK ESTIMATES FROM PGTW, KNES, AND RJTD. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM REMAINS IN A LOW (05-10 KNOT) VWS AREA WITH EXCELLENT DIVERGENCE. THE CYCLONE IS CURRENTLY TRACKING ALONG THE SOUTHERN PERIPHERY OF A STR EXTENSION. 3. FORECAST REASONING. A. NO SIGNIFICANT CHANGE IN THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY DUJUAN WILL MAINTAIN A WEST-NORTHWESTWARD TRAJECTORY THROUGH TAU 48 AS THE SYSTEM REMAINS UNDER THE STEERING INFLUENCE OF THE STR AND THE EXTENSION SLOWLY RETREATS TO THE EAST. EXPECT TY 21W TO BEGIN TO DECREASE IN INTENSITY DUE TO LOW OHC AND SOME LAND INTERACTION IN TAU 12 AS WELL AS COMPETING WITH THE MOUNTAINOUS TERRAIN OF TAIWAN AND LOWER SST VALUES OF THE TAIWAN STRAIT BY TAU 24. MAKING LANDFALL IN CHINA BEFORE TAU 36, TY DUJUAN WILL CONTINUE TO DECAY AS FRICTIONAL FORCES WILL CAUSE THE SYSTEM TO COMPLETELY DISSIPATE BY TAU 72. ADDITIONALLY, AN APPROACHING MID-LATITUDE TROUGH WILL FORCE THE SYSTEM TO TURN MORE POLEWARD AT THE END OF THE FORECAST PERIOD. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGHOUT THE FORECAST PERIOD LEADING TO HIGH CONFIDENCE IN THE JTWC FORECAST WHICH IS LAID CLOSE TO THE MULTI-MODEL CONSENSUS.// NNNN NNNN