WDPN31 PGTW 110900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (BAVI) WARNING NR 042// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 26.6N 123.2E INITIAL INTENSITY: 80 KTS GEOGRAPHIC REFERENCE: 247 NM WEST OF KADENA AB MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 20 KTS SIGNIFICANT WAVE HEIGHT: 52 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: A LARGE, NEARLY STEADY-STATE TYPHOON (TY) IS RAPIDLY APPROACHING MAINLAND CHINA, WITH A FORWARD MOTION OF 20 KTS, AN INCREASE FROM 13 KTS FROM SIX HOURS AGO. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A COMPLEX, CONVECTIVE STRUCTURE, CHARACTERIZED BY MULTIPLE CONCENTRIC RINGS AND A FORMATIVE INNER CORE FEATURING A 15-NM WIDE EYE. MICROWAVE IMAGERY FROM AN 110442Z AMSR-2 36 GHZ PASS CONFIRMS THIS STRUCTURE, EVIDENCING A CENTER SURROUNDED BY PARTIALLY OPEN RINGS MEASURING APPROXIMATELY 75 NM AND 200 NM IN DIAMETER. DESPITE A SUPPORTIVE ENVIRONMENT OF LOW VERTICAL WIND SHEAR (VWS) AND WARM SEA SURFACE TEMPERATURES (SST), THE SYSTEM'S PERSISTENT STRUGGLE TO CONSOLIDATE ITS INNER CORE CAN BE LARGELY ATTRIBUTED TO THE ENERGY-DISPERSIVE NATURE OF THESE CONCENTRIC RINGS. OCEAN SURFACE WIND DATA FROM THE AMSR2 AND A 110428Z OSCAT-3 PASSES REVEAL AN ASYMMETRIC WIND FIELD, WHERE THE STRONGEST WINDS ARE LOCATED IN THE NORTHEAST QUADRANT NEAR THE SECONDARY OUTER BAND. THESE SENSORS ALSO CONFIRM THAT THE EXTENT OF THE WIND FIELD IS CONTRACTING AS THE SYSTEM MAKES ITS FINAL APPROACH TO MAINLAND CHINA. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON RADAR IMAGERY AND THE EYE FEATURE ON MSI. THE INITIAL INTENSITY IS HELD AT 80 KTS WITH MEDIUM CONFIDENCE, BASED ON A BLEND OF THE SUBJECTIVE DVORAK FIXES OF T4.5-5.0 AND THE UPPER RANGE OF OBJECTIVE ESTIMATES FROM CIMSS, WHICH SPANS FROM 53 KTS TO 93 KTS. INITIAL WIND RADII BASIS: SCATTEROMETER DATA CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) CENTERED SOUTH OF HONSHU AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.5 - 77 KTS RJTD: T5.0 - 90 KTS RCTP: T4.5 - 77 KTS KNES: T5.5 - 102 KTS CIMSS SATCON: 84 KTS AT 110630Z CIMSS ADT: 53 KTS AT 110540Z CIMSS AIDT: 62 KTS AT 110540Z CIMSS D-MINT: 82 KTS AT 110510Z CIMSS D-PRINT: 75 KTS AT 110540Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 5-10 KTS SST: 27-29 CELSIUS OUTFLOW: MODERATE RADIAL ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: HIGH 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TY 09W (BAVI) WILL MAINTAIN A NORTHWESTWARD TRAJECTORY UNDER THE STEERING INFLUENCE OF THE STR NEAR HONSHU THROUGH TAU 24, MAKING LANDFALL BETWEEN THE NEIGHBORING CITIES OF WENZHOU AND TAIZHOU, CHINA. BY TAU 36 AND TAU 48, THE CIRCULATION WILL TRACK NEAR THE YANGTZE RIVER DELTA AND EXECUTE A POLEWARD TURN AS IT CROSSES THE LOW- TO MID-LEVEL RIDGE AXIS. THE STORM HAS LESS THAN 12 HOURS REMAINING OVER WARM SST. GIVEN THE SYSTEM'S COMPLEX CONVECTIVE STRUCTURE AND MASSIVE SPATIAL EXTENT, THE INTENSITY WILL CHANGE VERY LITTLE PRIOR TO CROSSING THE COAST. LANDFALL WILL OCCUR PRIOR TO TAU 12, WHICH WILL INITIATE A RAPID WEAKENING TREND. THE LAND WILL EFFECTIVELY CUT OFF THE CORE FROM ITS PRIMARY ENERGY SOURCE AND FRICTIONALLY DISRUPT THE VORTEX. CONSEQUENTLY, THE TROPICAL CIRCULATION WILL DISSIPATE BY TAU 48. BECAUSE THE WIND FIELD IS SO EXTENSIVE, A FETCH OF ELEVATED WINDS WILL PERSIST ALONG THE COASTLINE OF CENTRAL CHINA AND PUSH NORTHWARD INTO THE YELLOW SEA WELL AFTER THE CIRCULATION CENTER HAS MOVED FAR INLAND. MODEL DISCUSSION: THE GUIDANCE ENVELOPE IS VERY TIGHT THROUGH TAU 48, MEASURING LESS THAN 20 NM ACROSS AT THE POINT OF LANDFALL. THE PREVIOUS DIVERGENCE BETWEEN THE AI AND PHYSICS-BASED MODELS NO LONGER EXISTS, WITH BOTH SETS OF TRACKERS NOW IN STRONG AGREEMENT. THE JTWC FORECAST TRACK IS THUS LAID WITH HIGH CONFIDENCE ALONG THE MULTI-MODEL CONSENSUS. ALL OF THE RELIABLE INTENSITY AIDS, INCLUDING GFS, COAMPS-TC, HAFS-A, HWRF, AND DEEPMIND, DEPICT RAPID WEAKENING FOLLOWING LANDFALL AND SUBSEQUENT TRACK OVER LAND. THE JTWC INTENSITY FORECAST CONCURS WITH THIS MODEL PHILOSOPHY, SHOWING A SHARP DECAY OF TY 09W TO DISSIPATION BY TAU 48. FORECAST CONFIDENCE: TRACK 00-72 HR: HIGH INTENSITY 00-72 HR: HIGH// NNNN