MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (MUN) WARNING NR 01// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 05W (MUN), LOCATED APPROXIMATELY 83 NM SOUTHEAST OF HANOI, VIETNAM, HAS TRACKED NORTHWESTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A BROAD LOW-LEVEL CIRCULATION CENTER (LLCC) WITH LIMITED DEEP CONVECTION SHEARED TO THE SOUTHWEST DUE TO STRONG (25 TO 40 KNOTS) NORTHEASTERLY WIND SHEAR. HOWEVER, RECENT MICROWAVE IMAGERY (SPECIFICALLY, THE 031812Z AMSR2 36GHZ AND 031104Z WINDSAT 37GHZ IMAGES) AND SURFACE OBSERVATIONS FROM BACH LONG VI (48839) PROVIDE EVIDENCE THAT THE SYSTEM CONSOLIDATED INTO A TROPICAL CYCLONE AS IT TRACKED AWAY FROM HAINAN ISLAND WITH IMPROVED LOW- LEVEL BANDING AND STRUCTURE ALONG THE SOUTHERN AND EASTERN SEMICIRCLES. ALTHOUGH THE SYSTEM REMAINS BROAD, RECENT ASCAT DATA AND SURFACE OBSERVATIONS INDICATE 30-35 KNOT WINDS OVER THE SOUTHERN AND EASTERN SEMICIRCLES WITH A RADIUS OF MAXIMUM WINDS OF 35-50NM, WHICH IS TYPICAL OF A TROPICAL CYCLONE. OVERALL, THERE IS FAIR CONFIDENCE IN THE INITIAL POSITION BASED ON THE 031812Z AMSR2 IMAGE AND MULTIPLE SURFACE OBSERVATIONS. 3. FORECAST REASONING. A. THIS IS THE FIRST PROGNOSTIC REASONING MESSAGE AND SETS THE FORECAST PHILOSOPHY. B. TS 05W IS TRACKING NORTHWESTWARD ALONG THE SOUTHWEST PERIPHERY OF THE LOW-LEVEL SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTHEAST AND IS FORECAST TO CONTINUE TRACKING NORTHWESTWARD THROUGH THE FORECAST PERIOD. NUMERICAL MODEL GUIDANCE DIVERGES AS THE SYSTEM TRACKS INLAND, THEREFORE, THERE IS MODERATE CONFIDENCE IN THE JTWC FORECAST TRACK. TS MUN IS EXPECTED TO MAKE LANDFALL WITHIN THE NEXT SIX HOURS WITH RAPID WEAKENING DUE TO INCREASING FRICTIONAL EFFECTS AND PERSISTENT STRONG VERTICAL WIND SHEAR. THE SYSTEM SHOULD DISSIPATE OVER NORTHERN VIETNAM BY TAU 24.// NNNN NNNN