WDPN32 PGTW 071500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (DANAS) WARNING NR 015// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 27.1N 121.7E INITIAL INTENSITY: 45 KTS GEOGRAPHIC REFERENCE: 120 NM NORTH OF TAIPEI, TAIWAN MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 03 KTS SIGNIFICANT WAVE HEIGHT: 18 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY INDICATES A FRAGMENTED AND BROAD LOW-LEVEL CIRCULATION (LLCC) OF TROPICAL STORM (TS) 05W (DANAS). THE INITIAL POSITION IS ASSIGNED WITH LOW CONFIDENCE BASED ON LOW LEVEL FLOW PRESENT IN EIR, IN CONJUNCTION WITH VAGUELY INDICATED LLCC IN RADAR IMAGERY. ENVIRONMENTAL ANALYSIS REVEALS LOW (0-5 KTS) VERTICAL WIND SHEAR (VWS), WARM (28-29 C) SEA SURFACE TEMPERATURES (SST), DEEP-LAYER MOISTURE, AND MODERATE UPPER- LEVEL OUTFLOW. WITH THE VORTEX CURRENTLY POSITIONED WITHIN A FAVORABLE ENVIRONMENT, DEEP CONVECTION IS SLOWLY CONSOLIDATING WITHIN SPIRAL BANDS WRAPPING INTO A BROAD LLCC. THE INITIAL INTENSITY OF 45 KTS IS ESTIMATED WITH MEDIUM CONFIDENCE, DERIVED FROM A BLEND OF AGENCY DVORAK AND OBJECTIVE FIXES DETAILED BELOW. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: COMPETING STEERING ENVIRONMENT - NEAR-EQUATORIAL RIDGE (NER) TO THE SOUTHEAST AND BUILDING SUBTROPICAL RIDGE (STR) TO THE NORTHEAST AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T3.0 - 45 KTS RJTD: T3.0 - 45 KTS RCTP: T2.5 - 35 KTS KNES: T3.0 - 45 KTS DEMS: T3.0 - 45 KTS CIMSS SATCON: 52 KTS AT 071036Z CIMSS ADT: 57 KTS AT 071130Z CIMSS AIDT: 53 KTS AT 071130Z CIMSS D-MINT: 33 KTS AT 071039Z CIMSS D-PRINT: 31 KTS AT 071230Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 0-5 KTS SST: 28-29 CELSIUS OUTFLOW: MODERATE POLEWARD AND EQUATORWARD ANALYSIS CONFIDENCE: INITIAL POSITION: LOW INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: LOW 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TS 05W HAS SIGNIFICANTLY SLOWED DOWN SINCE LAST FORECAST AS A RESULT OF A BUILDING STR TO THE NORTHEAST, AND OCCURRING EARLIER THAN ANTICIPATED SHIFT IN THE STEERING ENVIRONMENT. TS DANAS IS HOWEVER STILL FORECAST TO CONTINUE ON A NORTHEASTWARD TRACK ALONG THE NORTHWESTERN PERIPHERY OF A NER TO THE SOUTHEAST, UNTIL THE RIDGE TO THE NORTH BUILDS ENOUGH TO STEER THE SYSTEM WESTWARD. AS A RESULT, THE SYSTEM IS EXPECTED TO MAKE LANDFALL OVER CHINA AROUND TAU 24. POST LANDFALL, THE SYSTEM IS FORECAST TO TRACK WEST-SOUTHWESTWARD OVER LAND AND DISSIPATE BY TAU 72. TS 05W IS FORECAST TO MAINTAIN INTENSITY AROUND 45 KTS UNTIL LANDFALL, AS A RESULT OF COMPETING IMPACT OF MARGINALLY FAVORABLE ENVIRONMENT AND LAND INTERACTION WITH THE EXTENDED PORTION OF THE VORTEX AND THE ASSOCIATED WIND FIELD. THEREAFTER, A GRADUAL WEAKENING PHASE AND EVENTUAL DISSIPATION BY TAU 72 ARE ANTICIPATED. MODEL DISCUSSION: NUMERICAL TRACK MODEL GUIDANCE EXHIBITS FAIR AGREEMENT THROUGHOUT THE FORECAST PERIOD, DEMONSTRATED BY A CROSS-TRACK SPREAD OF APPROXIMATELY 30 NM AT LANDFALL, AMONG MAJORITY OF THE MULTI-MODEL CONSENSUS MEMBERS. MAJOR OUTLIERS TO THIS GUIDANCE ARE GFS AND GFS ENSEMBLE, WHICH PREDICT A NEARLY FULL U-TURN AROUND TAU 24, RESULTING IN A SOUTHWESTWARD TRACK ALONG THE COASTLINE OF CHINA. INTENSITY GUIDANCE HOWEVER IN CONSISTENT AMONG NEARLY ALL CONSENSUS MEMBERS, INDICATING WEAKENING TREND BEGINNING BETWEEN TAUS 24 AND 36, ALIGNING WITH THE LANDFALL TIMELINE. ONE OUTLIER IN THIS INSTANCE IS THE GUIDANCE FROM COAMPS-TC, WHICH PREDICTS SLIGHT INTENSIFICATION THROUGH TAU 36, WITH THE SYSTEM REACHING 50-55 KTS PRIOR TO LANDFALL. ADDITIONALLY, SOME MODELS, LIKE GFS, INDICATE THAT THE SYSTEM WILL LINGER AROUND 30 KTS BEYOND TAU 72, LIKELY DUE TO ITS CURRENT ASSOCIATED TRACK ASSESSMENT MUCH CLOSER TO THE TAIWAN STRAIT, AS COMPARED TO OTHER AVAILABLE GUIDANCE. JTWC TRACK AND INTENSITY PREDICTIONS ARE THEREFORE ASSESSED WITH MEDIUM CONFIDENCE AND ARE LAID CLOSE TO THE MULTI-MODEL CONSENSUS. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM// NNNN