WDPN31 PGTW 010900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 20W (MINDULLE) WARNING NR 036// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 34.1N 143.1E INITIAL INTENSITY: 75 KTS GEOGRAPHIC REFERENCE: 183 NM EAST-SOUTHEAST OF YOKOSUKA, JAPAN MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 26 KTS SIGNIFICANT WAVE HEIGHT: 40 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS THE SYSTEM CONTINUED TO GRADUALLY DECAY AS EVIDENCED BY UNRAVELING RAIN BANDS AND WARMING CENTRAL CONVECTION. THE NORTHERN PERIPHERIES HAVE ELONGATED WITH EXPOSURE TO THE STRONG PREVAILING WESTERLIES. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE ON A CLUSTER OF WARM CENTRAL PIXELS IN THE EIR LOOP. THE INITIAL INTENSITY OF 75KTS IS AVERAGED WITH MEDIUM CONFIDENCE FROM THE AGENCY DVORAK ESTIMATES AND REFLECTS THE 6-HR DEGRADATION. ANALYSIS INDICATES THE ENVIRONMENT HAS BECOME UNFAVORABLE WITH INCREASING VWS, COOLING SSTS, AND THE INFLUX OF COLD DRY AIR AT THE LOWER LEVELS. THE CYCLONE IS TRACKING ALONG THE NORTHWESTERN PERIPHERY OF THE STR TO THE SOUTHEAST. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE SOUTHEAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.5 - 77 KTS RJTD: T4.5 - 77 KTS RCTP: T4.0 - 65 KTS KNES: T4.5 - 77 KTS CIMSS SATCON: 99 KTS AT 010355Z CIMSS ADT: 94 KTS AT 010540Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE VWS: 25-30 KTS SST: 26-27 CELSIUS OUTFLOW: STRONG POLEWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: MEDIUM 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TYPHOON MINDULLE WILL CONTINUE ON ITS CURRENT TRACK FOR THE REMAINDER OF THE FORECAST. THE HARSH ENVIRONMENT WILL CONTINUE TO DEGRADE THE SYSTEM. CONCURRENTLY, BY TAU 24, IT WILL BEGIN EXTRA-TROPICAL TRANSITION (ETT) AND BY TAU 36 WILL TRANSFORM INTO A 45-KT COLD CORE LOW WITH AN EXPANSIVE WIND FIELD AS IT PASSES SOUTHEAST OF THE KURIL ISLANDS. MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY TIGHT AGREEMENT, LENDING HIGH CONFIDENCE TO THE JTWC TRACK FORECAST. HOWEVER, GIVEN THE VARIABILITY ASSOCIATED WITH ETT, THERE IS ONLY MEDIUM CONFIDENCE IN THE INTENSITY FORECAST. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH INTENSITY 0 - 72 HR: MEDIUM// NNNN