WDPN31 PGTW 051500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 05W (AERE) WARNING NR 021// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 33.5N 133.2E INITIAL INTENSITY: 25 KTS GEOGRAPHIC REFERENCE: 73 NM SOUTHEAST OF IWAKUNI, JAPAN MOVEMENT PAST 6 HOURS: EASTWARD AT 11 KTS SIGNIFICANT WAVE HEIGHT: NOT APPLICABLE (OVER LAND) SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A DISORGANIZED SYSTEM THAT HAS BEEN SIGNIFICANTLY STRIPPED OF CONVECTION DUE TO HIGH VERTICAL WIND SHEAR AND FRICTIONAL EFFECTS FROM SHIKOKU'S RUGGED TERRAIN. THE LOW LEVEL CIRCULATION IS NO LONGER DISCERNIBLE ON SATELLITE AND COMPOSITE RADAR ANIMATION. THE INITIAL POSITION AND INTENSITY ARE PLACED WITH LOW CONFIDENCE BASED ON EXTRAPOLATION FROM THE CURRENT STORM MOTION AND TRIANGULATED, DEDUCED FROM NEARBY SURFACE WIND AND SEA LEVEL PRESSURE OBSERVATIONS. INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND RADII). CURRENT STEERING MECHANISM: NORTHERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) TO THE SOUTH-SOUTHEAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: NO CURRENT ESTIMATE FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE VWS: 20-25 KTS SST: 24-25 CELSIUS OUTFLOW: MODERATE POLEWARD ANALYSIS CONFIDENCE: INITIAL POSITION: LOW INITIAL INTENSITY: LOW 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 05W, SHOULD THE VORTEX SURVIVE, WILL CONTINUE EASTWARD ALONG THE NORTHERN PERIPHERY OF THE STEERING STR, CROSSING THE REMAINDER OF SHIKOKU AND THE SOUTHERN POINT OF HONSHU BEFORE EXITING BACK INTO THE PACIFIC OCEAN. BY TAU 36, THE CYCLONE WILL SLOW DOWN AND BECOME QUASI-STATIONARY AS A SECONDARY STR, BUILDING TO THE NORTH, ASSUMES STEERING AND, AFTER TAU 72, DRIVE THE CYCLONE NORTH- NORTHWESTWARD. FAVORABLE DIFFLUENCE ALOFT AND BAROCLINIC INTERACTION WILL PROMOTE INTENSIFICATION TO A PEAK OF 40KTS AT TAUS 24 TO 36 AS THE SYSTEM GRADUALLY TRANSFORMS INTO A SUBTROPICAL LOW. MODEL DISCUSSION: NUMERICAL MODELS REMAIN IN OVERALL GOOD AGREEMENT WITH THE CURRENT FORECAST SCENARIO THROUGH TAU 120. SOME SPREAD REMAINS IN THE ORIENTATION AND SPEED OF THE TRACK DURING THE CHANGE IN STEERING MECHANISM. CONFIDENCE IN THE TRACK AND INTENSITY FORECASTS IS NOW LOW DUE TO THE UNCERTAINTY IN THE INITIAL SURVIVAL OF THE VORTEX. FORECAST CONFIDENCE: TRACK 0 - 72 HR: LOW TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: LOW INTENSITY 72-120 HR: LOW// NNNN