WDPN31 PGTW 270300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 06W (CHAMPI) WARNING NR 025// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 29.8N 141.6E INITIAL INTENSITY: 35 KTS GEOGRAPHIC REFERENCE: 344 NM SOUTH-SOUTHEAST OF YOKOSUKA, JAPAN MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 17 KTS SIGNIFICANT WAVE HEIGHT: 18 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) LOOP DEPICTS AN EXPOSED LOW-LEVEL CIRCULATION (LLC) WEST OF A SMALL AREA OF CONVECTION, AS THE SYSTEM CONTINUES WEAKENING AND UNRAVELLING DUE TO HIGH VWS IN THE STRONG PREVAILING WESTERLIES. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A RAGGED LOW-LEVEL CIRCULATION FEATURE AS SEEN IN THE 262138Z SSMIS 91GHZ MICROWAVE IMAGE AND THE MSI LOOP. THE INITIAL INTENSITY OF 35 KTS IS IN LINE WITH MULTIPLE AGENCY DVORAK FIXES AND IS ASSESSED WITH HIGH CONFIDENCE DUE TO THE RAPID WEAKENING STATE OF THE SYSTEM AS IT ENCOUNTERS THE COOLER SSTS AND THE AFOREMENTIONED HIGHER VWS. INITIAL WIND RADII BASIS: SCATTEROMETER DATA. WIND RADII IN LINE WITH THE NORTHEAST QUADRANT BASED ON 270101Z PARTIAL ASCAT-B PASS. CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF THE STR TO THE EAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.5 - 35 KTS RJTD: T2.5 - 35 KTS KNES: T2.5 - 35 KTS CIMSS ADT: 31 KTS AT 262330Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY UNFAVORABLE VWS: 20-25 KTS SST: 24-25 CELSIUS OUTFLOW: MODERATE POLEWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH INITIAL WIND RADII: HIGH 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TS CHAMPI CONTINUES TRACKING NORTHEAST WELL TO THE EAST OF HONSHU, JAPAN ALONG THE POLEWARD SIDE OF THE STEERING STR. TS CHAMPI WILL BE 251NM EAST-SOUTHEAST OF YOKOSUKA, JAPAN BY TAU 12 AND CONTINUE WEAKENING UNDER THE HIGHLY UNFAVORABLE ENVIRONMENT. TS 06W WILL BEGIN INTERACTING WITH THE BAIU BOUNDARY WITHIN THE NEXT 12-24 HOURS, AS IT STARTS THE EXTRA-TROPICAL TRANSITION AND TRANSFORMS INTO A GALE-FORCE COLD-CORE LOW WITH AN EXPANSIVE WIND FIELD AS IT EMBEDS IN THE BAROCLINIC ZONE BETWEEN TAUS 24-36. MODEL DISCUSSION: NUMERIC MODELS REMAIN TIGHT THROUGH TAU 24 WITH A MAX CROSS-TRACK SPREAD OF 80NM, SPREADING TO A MAXIMUM OF 200NM BY TAU 36 AS ECMWF IS NOW THE SOLE LEFT OUTLIER LENDING HIGH CONFIDENCE IN THE JTWC TRACK FORECAST. THE JTWC INTENSITY FORECAST IS ALSO IN GOOD AGREEMENT WITH MODEL SOLUTIONS WHICH SHOWS A STEADY WEAKENING TREND. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH INTENSITY 0 - 72 HR: MEDIUM// NNNN