WDPN31 PGTW 061500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W (DOLPHIN) WARNING NR 043// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 26.5N 131.5E INITIAL INTENSITY: 80 KTS GEOGRAPHIC REFERENCE: 199 NM EAST OF KADENA AB MOVEMENT PAST 6 HOURS: WESTWARD AT 10 KTS SIGNIFICANT WAVE HEIGHT: 40 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TYPHOON (TY) 12W (DOLPHIN) WITH SPARSE PATCHES OF DEEP CONVECTION PEPPERED THROUGHOUT THE UPPER LEVEL CLOUD SHIELD, WITH NO REAL STRUCTURE OR CONSISTENCY. THE DRY MOAT STRETCHING INTO THE CORE FROM THE SOUTHERN PERIPHERY IS EXPANDING AND REDUCING DEEP CONVECTION THROUGHOUT THE STORM. ADDITIONALLY, THE NORTHWESTERN QUADRANT OF THE EYEWALL IS SHALLOWING AND THE EYE ITSELF IS NEARLY COMPLETELY FILLED. A SURFACE OBSERVATION FROM AMAMI OSHIMA IS REPORTING 44 KTS SUSTAINED AND 56 KT GUSTS, SUPPORTING BOTH THE INITIAL INTENSITY AND THE NORTHWESTERN QUADRANT 34 KT WIND RADII. THE ENVIRONMENT IS FAVORABLE, CHARACTERIZED BY LOW (5-10 KTS) VERTICAL WIND SHEAR (VWS), WARM (29-30 C) SEA SURFACE TEMPERATURES (SST), AND GOOD DIVERGENCE ALOFT. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE CLOUD-FILLED PINHOLE EYE IN ANIMATED EIR. THE INITIAL INTENSITY OF 80 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK FIXES AND CIMSS AUTOMATED INTENSITY ESTIMATES LISTED BELOW. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: THE SOUTHWESTERN PERIPHERY OF A MID- TO UPPER-LEVEL SUBTROPICAL RIDGE (STR) CENTERED OVER THE SEA OF JAPAN AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.5 - 77 KTS RJTD: T5.0 - 90 KTS RCTP: T4.5 - 77 KTS KNES: T5.0 - 90 KTS CIMSS ADT: 74 KTS AT 061200Z CIMSS AIDT: 78 KTS AT 061200Z CIMSS D-PRINT: 84 KTS AT 061100Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 0-5 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE RADIAL ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH 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: TY 12W IS FORECAST TO CONTINUE TRACKING WESTWARD TO WEST-NORTHWESTWARD THROUGH TAU 72 WHILE IT REMAINS UNDER THE STEERING INFLUENCE OF THE STR CENTERED OVER THE SEA OF JAPAN. A TROUGH PASSING OVER SIBERIA WILL WEAKEN THE STR, INDUCING SLOWER TRANSLATION SPEEDS BETWEEN TAU 24-48. AROUND TAU 72, THE STEERING RIDGE WILL REORIENT TO THE NORTHEAST OF THE SYSTEM AND BUILD, ACCELERATING TRACK SPEEDS AND INDUCING A NORTHWESTWARD CURVE. 12W IS FORECAST TO MAKE LANDFALL IN CHINA JUST AFTER TAU 72. REGARDING INTENSITY, 12W IS FORECAST TO MAINTAIN INTENSITY THROUGH TAU 12, THEN INTENSIFY SLIGHTLY AS IT TRACKS OVER A WARM POOL OF SLIGHTLY HIGHER OCEAN HEAT CONTENT ASSOCIATED WITH THE KUROSHIO CURRENT. THIS PERIOD OF SLIGHTLY HIGHER INTENSITIES WILL LAST APPROXIMATELY 48 HOURS, FROM TAU 24-60. AFTER, 12W IS FORECAST TO WEAKEN BETWEEN TAU 60-72 AS IT EXITS THE WARM POOL AND APPROACHES LAND. ONCE DOLPHIN MAKES LANDFALL, IT IS EXPECTED TO DRAMATICALLY WEAKEN AND FULLY DISSIPATE BY TAU 120. MODEL DISCUSSION: DETERMINISTIC MODEL TRACK GUIDANCE IS IN STRONG AGREEMENT THROUGH TAU 60, WITH THE EXCEPTION OF NAVGEM, WHICH HAS BEEN THE CONSISTENT AND SOLE EQUATORWARD OUTLIER. DISCOUNTING NAVGEM, THE JTWC TRACK FORECAST IS PLACED WITH HIGH CONFIDENCE FROM TAU 0-72. FOLLOWING TAU 60, THE CROSS-TRACK SPREAD DRAMATICALLY INCREASES, AS MODELS DISAGREE ON THE ORIENTATION OF THE STEERING RIDGE, ULTIMATELY INFLUENCING WHERE ALONG THE COAST 12W WILL MAKE LANDFALL AND THE NORTHWESTWARD TURN THEREAFTER. ADDITIONALLY, UNCERTAINTY IN THE LATE-TERM FORECAST ARISES AFTER 12W MAKES LANDFALL, AND THE POSSIBILITY OF ERRATIC MOTION DUE TO TERRAIN INTERACTION. AS A RESULT, THE JTWC TRACK FORECAST IS PLACED WITH LOW CONFIDENCE FROM TAU 72-120. RELIABLE INTENSITY AIDS ARE IN GOOD AGREEMENT THAT 12W WILL GENERALLY MAINTAIN INTENSITY THROUGH TAU 12-24, AND REINTENSIFY SLIGHTLY BETWEEN TAU 24-60. THE JTWC INTENSITY FORECAST IS PLACED IN LINE WITH THE HAFS-A SOLUTION AND THE MULTI-MODEL CONSENSUS. AS A RESULT, THE JTWC TRACK FORECAST IS ASSESSED WITH OVERALL MEDIUM CONFIDENCE, WITH UNCERTAINTY STEMMING FROM THE BRIEF REINTENSIFICATION IN THE NEAR-TERM FORECAST AND THE WEAKENING TREND FOLLOWING LANDFALL. FORECAST CONFIDENCE: TRACK 00-72 HR: HIGH TRACK 72-120 HR: LOW INTENSITY 00-72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN