WDPN32 PGTW 260900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 26W (TWENTYSIX) WARNING NR 001// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 11.7N 111.0E INITIAL INTENSITY: 25 KTS GEOGRAPHIC REFERENCE: 259 NM EAST-NORTHEAST OF HO CHI MINH CITY, VI MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 08 KTS SIGNIFICANT WAVE HEIGHT: 10 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: TROPICAL DEPRESSION 26W HAS RAPIDLY CONSOLIDATED OVER THE PAST SIX HOURS, AND REACHED WARNING INTENSITY. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A WELL DEFINED LOW LEVEL CIRCULATION CENTER (LLCC), WITH SHALLOW TO MID-LEVEL CONVECTIVE BANDING WRAPPING INTO THE LLCC. OVER THE PAST COUPLE OF HOURS, CONVECTION HAS BEGUN TO FLARE OVER THE ASSESSED CENTER, THOUGH THE OVERALL CONVECTIVE STRUCTURE REMAINS FAIRLY DISORGANIZED. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE PARTIALLY EXPOSED LLCC, SPIRAL BAND ANALYSIS AND THE FIRST HINTS OF A THE WESTERN SIDE OF THE LLCC ON AN ANIMATED RADAR MOSAIC FROM VIETNAM. THE INITIAL INTENSITY OF 25 KNOTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON A PGTW AND KNES DVORAK CURRENT INTENSITY ESTIMATE OF T1.5, A 260245Z ASCAT-B SCATTEROMETER PASS SHOWED A SWATH OF NORTH-SOUTH WINDS OVER 30 KNOTS TRAPPED BETWEEN THE VIETNAMESE COAST AND THE CENTER, WITH 20-25 KNOTS WRAPPING INTO THE CENTER ON THE SOUTH AND EASTERN SIDES. A 260600Z SHIP OBSERVATION APPROXIMATELY 20-NM SOUTHWEST OF THE CENTER INDICATED A 27 KNOT WIND, PROVIDING ADDITIONAL SUPPORT TO THE INTENSITY. THE ENVIRONMENT IS FAVORABLE FOR DEVELOPMENT, WITH LOW VWS, MODERATE POLEWARD AND EQUATORWARD OUTFLOW AND WARM SSTS. INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND RADII). CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A NORTH-SOUTH ORIENTED STR EXTENSION OVER THE PHILIPPINES. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T1.5 - 25 KTS KNES: T1.5 - 25 KTS FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 5-10 KTS SST: 28-29 CELSIUS OUTFLOW: MODERATE POLEWARD AND EQUATORWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH INITIAL WIND RADII: NOT APPLICABLE 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY. FORECAST DISCUSSION: TD 26W WILL CONTINUE TRACKING GENERALLY WEST-NORTHWEST THROUGH THE FORECAST PERIOD ALONG THE WESTERN PERIPHERY OF A STR COMPLEX EXTENDING FROM NORTHERN THAILAND TO HAINAN, AND THEN EXTENDING SOUTHWARD OVER THE PHILIPPINES. THE SYSTEM IS EXPECTED TO MAKE LANDFALL WITHIN THE NEXT 12 TO 18 HOURS NEAR NINH HOA, VIETNAM, THEN CONTINUE TRACKING INLAND. WHILE THE ENVIRONMENT IS FAVORABLE FOR DEVELOPMENT, THE LIMITED TIME OVER WATER WILL HINDER MUCH IN THE WAY OF INTENSIFICATION, WITH A PEAK OF 30 KNOTS EXPECTED PRIOR TO LANDFALL. DUE TO FUNNELING EFFECTS BETWEEN THE COASTLINE AND THE CENTER OF THE SYSTEM, GALE FORCE WINDS CAN BE EXPECTED WITHIN THE BAND OF HIGH WINDS IN THE WESTERN QUADRANT OF THE SYSTEM, BUT THE OVERALL INTENSITY IS NOT EXPECTED TO REACH 35 KNOTS. ONCE ASHORE, THE SYSTEM WILL RAPIDLY WEAKEN AND ULTIMATELY DISSIPATE OVER NORTHERN CAMBODIA BY TAU 36. MODEL DISCUSSION: TRACK AND INTENSITY GUIDANCE IS IN GOOD AGREEMENT THROUGH THE SHORT DURATION OF THE FORECAST PERIOD, LENDING HIGH CONFIDENCE TO THE JTWC FORECAST. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH INTENSITY 0 - 72 HR: HIGH// NNNN