WDPN32 PGTW 261500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 26W (TWENTYSIX) WARNING NR 002// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 11.8N 110.3E INITIAL INTENSITY: 30 KTS GEOGRAPHIC REFERENCE: 220 NM EAST-NORTHEAST OF HO CHI MINH CITY, VI MOVEMENT PAST 6 HOURS: WESTWARD AT 07 KTS SIGNIFICANT WAVE HEIGHT: 12 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY AND ANIMATED RADAR IMAGERY SHOW A RAGGED LOW LEVEL CIRCULATION CENTER (LLCC) LOCATED ON THE EASTERN SIDE OF AN AREA OF SYMMETRICAL CONVECTION. THE BULK OF THE DEEP CONVECTION IS SHEARED TO THE WEST, ALONG AND OVER THE VIETNAMESE COASTLINE. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE DUE TO THE OBSCURED AND RAGGED NATURE OF THE LLCC IN EIR AND RADAR IMAGERY. THE INITIAL INTENSITY OF 30 KNOTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE CONGRUENCE OF SUBJECTIVE AND OBJECTIVE DVORAK CURRENT INTENSITY ESTIMATES. ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE WITH AN UPPER-LEVEL ANTICYCLONE TO THE NORTH PROVIDING GOOD POLEWARD AND EQUATORWARD OUTFLOW AND LOW VWS. THOUGH A TONGUE OF SLIGHTLY COOLER WATER PREVAILS DIRECTLY ALONG THE COASTLINE, OVERALL SSTS REMAIN SUPPORTIVE. THE ONLY LIMITING FACTOR AT PRESENT IS THE PROXIMITY TO LAND AND THE SHORT TIME REMAINING PRIOR TO LANDFALL. INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND RADII). CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF LOW- TO MID-LEVEL SUBTROPICAL RIDGE (STR) TO THE NORTH. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.0 - 30 KTS KNES: T2.0 - 30 KTS CIMSS ADT: 28 KTS AT 261140Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 10-15 KTS SST: 28-29 CELSIUS OUTFLOW: MODERATE POLEWARD AND EQUATORWARD OTHER FACTORS: PROXIMITY TO LAND. ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: HIGH INITIAL WIND RADII: NOT APPLICABLE 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TD 26W HAS SLOWED SLIGHTLY AS IT APPROACHES THE COAST OF VIETNAM, WITH FORWARD SPEEDS DOWN TO 07 KNOTS DUE TO A SLIGHT WEAKENING OF THE MID-LEVEL GRADIENT TO THE NORTH. THE GRADIENT IS EXPECTED TO TIGHTEN UP OVER THE NEXT FEW HOURS AND TD 26W IS EXPECTED TO PICK UP SPEED ONCE MORE, AND IS EXPECTED TO MAKE LANDFALL WITHIN THE NEXT SIX TO TEN HOURS NEAR CAM RANH BAY, THEN CONTINUE TRACKING INLAND OVER NORTHERN CAMBODIA. AS THE FIRST FORECAST POINT IS OVER LAND, THE FORECAST CALLS FOR A STEADY 30 KNOT INTENSITY FOR THE FIRST 12 HOURS. HOWEVER, A SLIGHTLY HIGHER INTENSITY NEAR 35 KNOTS IS POSSIBLE IN THE NEXT SIX HOURS PRIOR TO LANDFALL, ESPECIALLY ALONG THE WESTERN PORTION OF THE CIRCULATION DUE TO THE PRESENCE OF A BAND OF ENHANCED NORTHERLY FLOW TRAPPED BETWEEN THE COASTLINE AND THE CIRCULATION CENTER. AFTER MAKING LANDFALL, THE SYSTEM WILL RAPIDLY ERODE DUE TO TERRAIN INTERACTION, AND IS EXPECTED TO FULLY DISSIPATE OVER NORTHERN CAMBODIA BY TAU 36. MODEL DISCUSSION: TRACK GUIDANCE ARE BOTH IN GOOD AGREEMENT THROUGH THE DURATION OF THE FORECAST PERIOD, LENDING HIGH CONFIDENCE TO THE TRACK FORECAST. INTENSITY GUIDANCE IS FOR THE MOST PART IN GOOD AGREEMENT, WITH THE HWRF INDICATING NEAR-TERM INTENSIFICATION TO 35 KNOTS PRIOR TO LANDFALL, WHILE THE REMAINDER OF THE GUIDANCE SHOWS STEADY WEAKENING. AS MENTIONED, WITH THE FIRST FORECAST POINT AT TAU 12 OVER LAND, THE PEAK INTENSITY IS LIKELY TO BE REACHED AROUND TAU 6 AND IS NOT CAPTURED IN THE FORECAST DIRECTLY. OVERALL THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST INTENSITY. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH INTENSITY 0 - 72 HR: HIGH// NNNN