WDPN32 PGTW 261500 MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 21W WARNING NR 09// RMKS/ 1. FOR METEOROLOGISTS. 2. 12 HOUR SUMMARY AND ANALYSIS. A. TROPICAL DEPRESSION (TD) 21W (HAITANG), LOCATED APPROXIMATELY 135 NM EAST OF HUE, VIETNAM, HAS TRACKED WEST-SOUTHWESTWARD AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY CONTINUES TO DEPICT A FULLY-EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH DISORGANIZED DEEP CONVECTION FLARING WEST OF THE CENTER DUE TO MODERATE EASTERLY VERTICAL WIND SHEAR (20 KNOTS) AND BROAD DIFFLUENCE ALOFT. A 261235Z SSMIS 37 GHZ IMAGE INDICATES CONVECTIVE BANDING WRAPPING INTO A BROAD, DEFINED CENTER. THIS IMAGE SUPPORTS THE CURRENT POSITION AND RECENT TRACK MOTION WITH GOOD CONFIDENCE. THE CURRENT INTENSITY IS ASSESSED AT 30 KNOTS BASED ON DVORAK ESTIMATES RANGING FROM 25-30 KNOTS AND RECENT ASCAT DATA. 3. FORECAST REASONING. A. NO CHANGE TO FORECAST PHILOSOPHY. B. TD 21W HAS WEAKENED SLIGHTLY AND HAS ACCELERATED WESTWARD UNDER THE STEERING INFLUENCE OF THE LOW- TO MID-LEVEL SUBTROPICAL RIDGE POSITIONED NORTH OF HAINAN ISLAND. THE AVAILABLE MODELS ARE IN GOOD AGREEMENT. TD 21W IS EXPECTED TO MAKE LANDFALL NEAR HUE BY TAU 12 AND WILL DISSIPATE OVER LAND BY TAU 24.// NNNN