WDPN32 PGTW 091500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 03W (THREE) WARNING NR 003// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 10.9N 126.7E INITIAL INTENSITY: 25 KTS GEOGRAPHIC REFERENCE: 401 NM EAST-SOUTHEAST OF MANILA, PHILIPPINES MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 03 KTS SIGNIFICANT WAVE HEIGHT: 10 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A WEAK AND IRREGULAR SYSTEM WITH FRAGMENTED FORMATIVE BANDS, MOSTLY WRAPPING IN FROM THE NORTH INTO A PARTIALLY EXPOSED LOW LEVEL CIRCULATION (LLC). THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE PARTIALLY EXPOSED LLC IN THE EIR LOOP. THE INITIAL INTENSITY OF 25KTS IS BASED ON OVERALL ASSESSMENT OF AGENCY AND AUTOMATED DVORAK ESTIMATES AND REFLECTS THE UNCHANGED 6-HR EIR SIGNATURE. ANALYSIS INDICATES A MARGINALLY FAVORABLE ENVIRONMENT WITH MODERATE VWS, MODERATE POLEWARD OUTFLOW, AND WARM SST. THE CYCLONE IS QUASI-STATIONARY (QS) IN THE PHILIPPINE SEA WHERE IT IS EMBEDDED IN A SHALLOW TROUGH WITH EASTERLY TRADEWINDS TO THE NORTH AND A BELT OF WESTERLIES TO THE SOUTH. INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND RADII). CURRENT STEERING MECHANISM: QUASI-STATIONARY IN A SHALLOW TROUGH WITH EASTERLY TRADEWINDS TO THE NORTH AND A BELT OF WESTERLIES TO THE SOUTH. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T1.5 - 25 KTS CIMSS ADT: 30 KTS AT 090840Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 15-20 KTS SST: 28-29 CELSIUS OUTFLOW: MODERATE POLEWARD ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM 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: TD 03W WILL REMAIN IN A QS MODE IN THE WEAK STEERING ENVIRONMENT UP TO TAU 36. AFTERWARD IT WILL BEGIN TO TRACK EAST-NORTHEASTWARD AS IT GETS PULLED INTO AN APPROACHING CYCLONE THAT IS BIGGER AND STRONGER (TS 02W). THIS BINARY INTERACTION WILL INHIBIT ANY SIGNIFICANT DEVELOPMENT OF TD 03W RESULTING IN WEAK INTENSIFICATION TO A PEAK OF 40KTS BY TAU 36 AND SUSTAINED, AT BEST, THROUGH THE REMAINDER OF ITS LIFESPAN AS A TC. BY TAU 72, TD 03W WILL BEGIN TO BE ABSORBED BY TS 02W AND BY TAU 96, WILL LOSE ITS CIRCULATION AND BECOME EMBEDDED IN THE SOUTHERN FEEDER BAND OF THE LARGER AND STRONGER CYCLONE, ESSENTIALLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE. MODEL DISCUSSION: NUMERICAL MODELS ARE WIDELY SPREAD UP TO TAU 36; HOWEVER, AFTER TAU 36, THE MAJORITY OF THE MEMBERS TRACK THE VORTEX EAST-NORTHEASTWARD. GIVEN THE LARGE VARIABILITY IN THE FIRST 36HRS, THERE IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST. FORECAST CONFIDENCE: TRACK 0 - 72 HR: LOW TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: LOW INTENSITY 72-120 HR: LOW// NNNN