WDPN32 PGTW 312100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 13W (THIRTEEN) WARNING NR 005// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 23.0N 130.3E INITIAL INTENSITY: 25 KTS GEOGRAPHIC REFERENCE: 250 NM SOUTHEAST OF KADENA AB, OKINAWA, JAPAN MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 18 KTS SIGNIFICANT WAVE HEIGHT: 10 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A WEAK, FULLY EXPOSED SYSTEM WITH THE CONVECTION OFFSET TO THE SOUTH. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EXPOSED LOW LEVEL CIRCULATION CENTER IN THE EIR LOOP. THE INITIAL INTENSITY IS ASSESSED WITH HIGH CONFIDENCE BASED ON AGENCY DVORAK ESTIMATES AND CONSISTENT WITH THE WEAK EIR SIGNATURE. ANALYSIS INDICATES THE ENVIRONMENT IS UNFAVORABLE WITH MODERATE TO STRONG VWS AND SUBSIDENCE FROM THE OUTFLOW OF TY 12W OFFSETTING THE WARM SST AND MEDIUM EQUATORWARD OUTFLOW. INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND RADII). CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE NORTH. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T1.5 - 25 KTS KNES: T1.0 - 25 KTS CIMSS ADT: 35 KTS AT 311740Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE VWS: 20-25 KTS SST: 30-31 CELSIUS OUTFLOW: MODERATE EQUATORWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH 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 13W IS EXPECTED TO TRACK NORTHWESTWARD TOWARD OKINAWA UNDER THE STR. AFTER TAU 12, IT WILL TRACK WEST-SOUTHWESTWARD AS IT GETS ABSORBED IN THE CIRCULATION AROUND TY 12W. THE UNFAVORABLE CONDITIONS WILL SUSTAIN ITS CURRENT INTENSITY, AT BEST, UP TO TAU 12. AFTERWARD IT WILL DISSIPATE DUE TO THE HIGH VWS AND STRONG OUTFLOW FROM 12W BY TAU 24, VERY LIKELY SOONER. MODEL DISCUSSION: NUMERICAL MODELS ARE NOT HANDLING THE FORECAST TRACK FOR TD 13W VERY WELL. THE JTWC TRACK FORECAST IS BASED ON NUMERIC FIELDS DATA WITH LOW CONFIDENCE. FORECAST CONFIDENCE: TRACK 0 - 72 HR: LOW INTENSITY 0 - 72 HR: LOW// NNNN