WDPN31 PGTW 110900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 01W (WUTIP) WARNING NR 004// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 16.7N 112.4E INITIAL INTENSITY: 30 KTS GEOGRAPHIC REFERENCE: 240 NM EAST OF DA NANG, VIETNAM MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 15 KTS SIGNIFICANT WAVE HEIGHT: 12 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A PARTIALLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH BUILDING CENTRAL CONVECTION SHEARED TO THE SOUTHWEST. LOW-LEVEL CLOUD BANDS ARE VISIBLE SURROUNDING THE CIRCULATION. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE CLEAR-CUT CIRCULATION CENTER IDENTIFIABLE IN THE AFOREMENTIONED ANIMATED MSI. THE INITIAL INTENSITY OF 30 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON PERSISTENCE FROM AN EARLIER 110202Z METOP-C PARTIAL ASCAT IMAGE REVEALING 25-30KTS IN THE SOUTHWESTERN PERIPHERY OF THE CIRCULATION COMPLEMENTED BY THE AGENCY AND OBJECTIVE FIXES LISTED BELOW. INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND RADII). CURRENT STEERING MECHANISM: A SUBTROPICAL RIDGE TO THE NORTHEAST AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.0 - 30 KTS RJTD: T2.0 - 30 KTS RCTP: T2.0 - 30 KTS KNES: T1.5 - 25 KTS CIMSS ADT: 31 KTS AT 110530Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 15-20 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE EQUATORWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM 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: TROPICAL DEPRESSION 01W WILL CONTINUE TRACKING WEST-NORTHWESTWARD FOR THE NEXT 48 HOURS ON THE SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL RIDGE POSITIONED TO THE NORTHEAST. BETWEEN TAU 48 AND 72, THE SYSTEM WILL CROSS THE RIDGE AXIS, TRANSITIONING TO A NORTHEASTERN TRACK AFTER TAU 72. AS THE SYSTEM WEAKENS AND BECOMES SHALLOW AFTER TAU 48, THE TRACK SPEED WILL GRADUALLY INCREASE. TD 01W WILL SLOWLY INTENSIFY DESPITE 15-20KT VERTICAL WIND SHEAR INDUCED BY A TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) CELL TO THE NORTHEAST WHICH FILLS GRADUALLY THROUGHOUT THE FORECAST. THE SYSTEM WILL REACH A PEAK OF 55KTS BY TAU 48, BUT TOPOGRAPHIC INTERACTION WITH HAINAN ISLAND AND MAINLAND CHINA WILL FORCE WEAKENING TO DISSIPATION BY THE END OF THE FORECAST PERIOD. MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE HAS A WIDE SPREAD OF MEMBERS IN THE ALONG TRACK FORECAST, WITH THE SLOWEST MEMBER BEING GFS AND THE FASTEST BEING GALWEM. THE JTWC TRACK LIES SLIGHTLY WEST OF CONSENSUS AND CLOSER TO ECMWF, HAFS-A, AND HWRF, WHICH ALL REFLECT THE WEST-NORTHWESTWARD TRACK THAT THE SYSTEM IS CURRENTLY ON. THE INTENSITY GUIDANCE INDICATES A PEAK INTENSITY BETWEEN TAU 36-48, AND A RANGE OF 40-65KTS. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: LOW INTENSITY 72-120 HR: LOW// NNNN