WDPN31 PGTW 071500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 08W (EIGHT) WARNING NR 001// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 19.2N 108.0E INITIAL INTENSITY: 25 KTS GEOGRAPHIC REFERENCE: 160 NM SOUTHEAST OF HANOI, VIETNAM MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 15 KTS SIGNIFICANT WAVE HEIGHT: 10 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A RAGGED DEEP CONVECTIVE STRUCTURE BEGINNING TO LOCALIZE AROUND A LOW-LEVEL CIRCULATION CENTER (LLCC) WITH DEEP CONVECTIVE BURSTS OVER MAINLY THE WESTERN AND SOUTHERN SEMICIRCLES. A PARTIAL 071144Z SSMIS 91GHZ MICROWAVE IMAGE INDICATES FRAGMENTED, FORMATIVE BANDING PRIMARILY OVER THE WESTERN SEMICIRCLE. THE INITIAL POSITION IS PLACED WITH LOW CONFIDENCE BASED ON THE EIR LOOP AND THE PARTIAL MICROWAVE IMAGE. THE INITIAL INTENSITY OF 25 KTS IS ASSESSED WITH LOW CONFIDENCE BASED ON MULTIPLE AGENCY DVORAK ESTIMATES OF T1.0, CONSISTENT WITH THE OVERALL STRUCTURE. THE ENVIRONMENTAL ANALYSIS IS MARGINALLY FAVORABLE DUE TO THE STRONG UPPER-LEVEL EASTERLY OUTFLOW, WHICH IS PREDOMINATELY OFFSET BY THE MODERATE TO HIGH VERTICAL WIND SHEAR. INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND RADII). CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTHEAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T1.0 - 25 KTS RJTD: T1.0 - 25 KTS FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 20-25 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE WESTWARD ANALYSIS CONFIDENCE: INITIAL POSITION: LOW INITIAL INTENSITY: LOW INITIAL WIND RADII: NOT APPLICABLE 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY. FORECAST DISCUSSION: TD 08W IS FORECAST TO TRACK AROUND THE SOUTHWEST PERIPHERY OF THE DEEP-LAYERED STR TOWARD VIETNAM THROUGH THE REMAINDER OF THE FORECAST PERIOD. THE SYSTEM AT CURRENT IS DISORGANIZED BUT WILL CONSOLIDATE AROUND THE LLCC AS THE STRONG VWS WILL BEGIN TO DECREASE TO 10-15KTS WITHIN THE NEXT 12 HOURS. ONCE THE VWS DECREASES THE STRONG OUTFLOW WILL HELP THE INTENSITY REACH A PEAK OF 30 KTS BEFORE MAKING LANDFALL SOUTH OF HANOI, VIETNAM, JUST AFTER TAU 12. THEREAFTER, THE SYSTEM WILL MAKE LANDFALL AND BEGIN DISSIPATION OVER THE RUGGED TERRAIN OVER VIETNAM AND LAOS. MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN TIGHT AGREEMENT ON THE FORECAST TO MAKE LANDFALL JUST SOUTH OF HANOI, VIETNAM, WITH A VERY SMALL CROSS-TRACK SPREAD OF ONLY 46NM THROUGH TAU 24. THE JTWC FORECAST TRACK IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS, BUT SLIGHTLY EQUATORWARD TOWARD THE BULK OF THE MODEL SOLUTIONS, WHICH ARE ON THE SOUTHERN EDGE OF THE AIDS ENVELOPE. AFUM AND EEMN REMAIN THE TWO MOST SIGNIFICANT POLEWARD OUTLIERS FROM CONSENSUS. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM// NNNN