WDPN32 PGTW 060900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 05W (DANAS) WARNING NR 010// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 22.2N 118.8E INITIAL INTENSITY: 80 KTS GEOGRAPHIC REFERENCE: 229 NM SOUTHWEST OF TAIPEI, TAIWAN MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 08 KTS SIGNIFICANT WAVE HEIGHT: 28 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A RECENTLY DEVELOPED IRREGULAR EYE FEATURE OF TYPHOON (TY) 05W (DANAS). THE INITIAL POSITION IS THEREFORE PLACED WITH HIGH CONFIDENCE BASED ON THE VISIBLE SATELLITE IMAGERY. TY 05W IS CURRENTLY TRACKING NORTHEASTWARD TOWARD THE WESTERN COAST OF TAIWAN. DRIVEN BY HIGHLY FAVORABLE ENVIRONMENTAL CONDITIONS, THE SYSTEM HAS INTENSIFIED 25 KTS OVER THE LAST 24 HOURS AND EXHIBITS WELL DEVELOPED SPIRAL BANDS OF DEEP CONVECTION, WITH THE BANDING OVER SOUTHERN SEMICIRCLE EXTENDING AS FAR AS EAST OF TAIWAN. THE RAGGED EYE FEATURE HAS TEMPERATURE OF ABOUT -8 C, WHILE THE COLDEST CLOUD TOPS ARE ESTIMATED AT -83 C. ADDITIONAL ENVIRONMENTAL ANALYSIS INDICATES THAT TY 05W IS IN A HIGHLY FAVORABLE ENVIRONMENT IDENTIFIED BY LOW (5-10 KTS) VERTICAL WIND SHEAR (VWS), WARM (29-30 C) SEA SURFACE TEMPERATURES (SST) AND STRONG RADIAL OUTFLOW. THE INITIAL INTENSITY OF 80 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK AND OBJECTIVE INTENSITY ESTIMATES LISTED BELOW. INITIAL WIND RADII BASIS: 060052Z METOP-B AND 060143 METOP-C ASCAT PASSES CURRENT STEERING MECHANISM: DEEP LAYER NEAR-EQUATORIAL RIDGE (NER) TO THE SOUTHEAST AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T5.0 - 90 KTS RJTD: T4.0 - 65 KTS RCTP: T5.0 - 90 KTS KNES: T5.0 - 90 KTS CIMSS SATCON: 84 KTS AT 060530Z CIMSS ADT: 63 KTS AT 060600Z CIMSS AIDT: 67 KTS AT 060600Z CIMSS D-MINT: 74 KTS AT 060455Z CIMSS D-PRINT: 76 KTS AT 060600Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE VWS: 5-10 KTS SST: 29-30 CELSIUS OUTFLOW: STRONG RADIAL ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: MEDIUM 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: TY 05W IS NOW FORECAST TO PASS DIRECTLY OVER WESTERN AND NORTHERN TAIWAN FORECAST DISCUSSION: TY 05W IS FORECAST TO TRACK NORTHEASTWARD UNDER THE INFLUENCE OF A NER TO THE SOUTHEAST THROUGH TAU 36, HOWEVER RECENT NUMERICAL MODEL GUIDANCE INDICATES THAT THE RIDGE IS BEGINNING TO REALIGN ALONG A SOUTHWEST-NORTHEAST AXIS AND THEREFORE LEADING TO THE TRACK SHIFTING SLIGHTLY EASTWARD. AS A RESULTS, TY 05W IS NOW EXPECTED TO MAKE LANDFALL OVER SOUTHWESTERN TAIWAN, NEAR QIGU DISTRICT, WITHIN THE NEXT 6 TO 12 HOURS. PRIOR TO THAT, THE SYSTEM IS EXPECTED TO INTENSIFY FURTHER, POTENTIALLY UP TO 90-95 KTS, BEFORE THE WIND FIELD IS EXPOSED TO THE MOUNTAIN RANGES OF TAIWAN. THE WESTERN FOOTHILLS, AS WELL AS THE XUESHAN RANGE ARE EXPECTED TO HAVE A SIGNIFICANT IMPACT ON WEAKENING OF THE SYSTEM. AFTER CROSSING THE ISLAND, TY DANAS IS FORECAST TO WEAKEN TO APPROXIMATELY 60 KTS AND CONTINUE TRACKING NORTHEASTWARD UNTIL AROUND TAU 36. AT THAT TIME, A SUBTROPICAL RIDGE (STR) TO THE NORTH WILL ASSUME STEERING AND PUSH THE SYSTEM WESTWARD. ANOTHER LANDFALL, OVER MAINLAND CHINA, IS EXPECTED BETWEEN TAUS 48 AND 72. AFTER THAT, TY 05W IS EXPECTED TO BEGIN DISSIPATING, WHICH IS FORECAST TO BE COMPLETED AT OR BEFORE TAU 96. INTENSITY, PARTICULARLY DURING THE UPCOMING 24-36 HOURS, IS ASSESSED WITH LOW CONFIDENCE, DUE TO SIGNIFICANT UNCERTAINTY ASSOCIATED WITH THE TRACK OF THE SYSTEM, AND THEREFORE IMPACTS OF THE TERRAIN INTERACTION ON INTENSIFICATION OR WEAKENING. MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU 24, AS WITNESSED BY A CROSS-TRACK SPREAD OF 70 NM. MAJORITY OF THE MODEL GUIDANCE, INCLUDING THE MULTI-MODEL CONSENSUS ARE NOW INDICATING LANDFALL OVER WESTERN TAIWAN, WITH JUST ECMWF ENSEMBLE, JGSM AND UKMET ENSEMBLE KEEPING THE TRACK ENTIRELY OVER THE TAIWAN STRAIT. ADDITIONALLY, TRACK FORECAST UNCERTAINTY INCREASES IN REGARD TO THE TIMELINE OF THE WESTWARD TURN, AND THE SUBSEQUENT LANDFALL OVER MAINLAND CHINA, AS WITNESSED BY A 155 NM CROSS-TRACK SPREAD AT LANDFALL. INTENSITY GUIDANCE IS IN FAIR AGREEMENT AS WELL, WITH ALL GUIDANCE INDICATING THAT TY 05W HAS ALREADY OR WILL SOON REACH PEAK INTENSITY AND INDICATING CONSISTENT WEAKENING THROUGHOUT THE FORECAST PERIOD. JTWC INTENSITY FORECAST IS ASSESSED WITH ONLY MEDIUM CONFIDENCE, DUE TO THE POSSIBILITY OF THE STORM STAYING OVER WARM WATERS OF TAIWAN STRAIT AND THEREFORE BEING ABLE TO MAINTAIN STRUCTURAL INTEGRITY OF THE VORTEX AND CONVECTIVE BENDING, DESPITE THE DETRIMENTAL IMPACTS OF LAND INTERACTION. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN