WDPN31 PGTW 111500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 04W (SINLAKU) WARNING NR 011// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 9.0N 151.1E INITIAL INTENSITY: 85 KTS GEOGRAPHIC REFERENCE: 465 NM SOUTHEAST OF NAVSTA GUAM MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 04 KTS SIGNIFICANT WAVE HEIGHT: 30 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS CONSOLIDATION OF DEEP CONVECTIVE BANDING SPIRALING INTO A CENTRAL DENSE OVERCAST (CDO) FEATURE THAT IS OBSCURING THE LOW-LEVEL CIRCULATION CENTER (LLCC) OF TYPHOON (TY) 04W (SINLAKU). THE INITIAL POSITION IS DETERMINED WITH HIGH FIDELITY, PINPOINTED BY THE CENTRAL CONVECTIVE CONVERGENCE, APPARENT IN THE SHORTWAVE INFRARED IMAGERY LOOP, SUPPORTED BY THE EXTRAPOLATION FROM A 110809Z SENTINEL-1C SAR WIND SPEED PRODUCT. THE INITIAL INTENSITY OF 85 KTS IS ALSO ASSESSED WITH HIGH CONFIDENCE, SUPPORTED BY STRONG AGREEMENT AMONG OBJECTIVE INTENSITY AIDS AND AGENCY DVORAK ESTIMATES, ADDITIONALLY CORROBORATED BY THE AFOREMENTIONED SAR PASS SHOWING PEAK WIND SPEEDS OF 83-86 KTS. A COMPREHENSIVE ENVIRONMENTAL DIAGNOSIS REVEALS EXCEPTIONALLY CONDUCIVE CONDITIONS FOR INTENSIFICATION, CHARACTERIZED BY HIGH OCEANIC HEAT CONTENT WITH SEA SURFACE TEMPERATURES OF 28-29 C, A MOIST TROPOSPHERIC COLUMN, NEGLIGIBLE VERTICAL WIND SHEAR AT 5-10 KTS, AND ROBUST, RADIAL UPPER-LEVEL OUTFLOW. THIS EFFICIENT VENTILATION IS FURTHER AUGMENTED BY THE PRESENCE OF AN UPPER-LEVEL ANTICYCLONE TO THE NORTHEAST AND A NEAR-EQUATORIAL RIDGE TO THE EAST. INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK CURRENT STEERING MECHANISM: WEAK STEERING ENVIRONMENT WITH A NEAR-EQUATORIAL RIDGE (NER) TO THE SOUTHEAST AND A SUBTROPICAL RIDGE (STR) TO THE NORTHWEST AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T5.0 - 90 KTS RJTD: T5.0 - 90 KTS RCTP: T5.0 - 90 KTS KNES: T5.0 - 90 KTS CIMSS ADT: 82 KTS AT 111130Z CIMSS AIDT: 82 KTS AT 111130Z CIMSS D-MINT: 80 KTS AT 110740Z CIMSS D-PRINT: 74 KTS AT 111230Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE VWS: 5-10 KTS SST: 28-29 CELSIUS OUTFLOW: STRONG RADIAL ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH 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 SINLAKU CONTINUES TO SLOWLY TRACK NORTHWESTWARD, DRIVEN BY A GENERALLY WEAK AMBIENT STEERING FLOW. MODEL DATA INDICATES THAT A NORTHWARD EXTENSION OF THE NEAR-EQUATORIAL RIDGE (NER) IS PROGGED TO BUILD AND BECOME THE PRIMARY STEERING MECHANISM. CONSEQUENTLY, TY 04W IS FORECAST TO ACCELERATE ON A GENERALLY NORTHWESTWARD TRAJECTORY TOWARD THE SOUTHERN MARIANA ISLANDS. THE PERSISTENCE OF A HIGHLY FAVORABLE ATMOSPHERIC AND OCEANIC REGIME IS EXPECTED TO FUEL A PERIOD OF RAPID INTENSIFICATION, WITH A PEAK INTENSITY OF 125 KTS PROJECTED AROUND TAU 48, PRIOR TO THE CLOSEST POINT OF APPROACH TO THE ISLANDS. THE EXPANSIVE NATURE OF THE WIND FIELD WILL LIKELY BRING GALE FORCE WINDS (34 KT WIND RADII) WITHIN RANGE OF SOUTHERN MARIANAS BETWEEN TAUS 36 AND 48. AROUND TAU 72, TY 04W IS EXPECTED TO INITIATE RECURVATURE AROUND THE SOUTHWESTERN PERIPHERY OF THE BUILDING RIDGE EXTENSION. A GRADUAL WEAKENING TREND IS ANTICIPATED TO COMMENCE AT THAT JUNCTURE AS VERTICAL WIND SHEAR BEGINS TO MODESTLY INCREASE. MODEL DISCUSSION: NUMERICAL MODEL PREDICTION GUIDANCE IS IN FAIR AGREEMENT ON THE GENERAL STEERING PATTERN AND THE ULTIMATE RECURVATURE SCENARIO. TRACK MODEL GUIDANCE HAS IMPROVED AGAIN SINCE THE LAST WARNING, AS WITNESSED BY A CROSS-TRACK SPREAD OF LESS THAN 70 NM AMONG THE MULTI-MODEL CONSENSUS MEMBERS AND AROUND THE TIME OF CPA TO THE ISLAND CHAIN. THE INDIVIDUAL TRACKERS CONVERGE WITHIN AN AREA BETWEEN THE ISLANDS OF GUAM AND TINIAN, WITH THE TRACK CONSENSUS MEAN NOW POSITIONED JUST NORTHWEST OF GUAM. UNCERTAINTY IN THE LONG TERM TRACK FORECAST IS STILL HIGH, AND WILL DEPEND HEAVILY ON THE EVOLUTION OF THE DEEP-LAYER STEERING PATTERN. CURRENTLY ALL MODELS FAVOR THE RECURVATURE SCENARIO, HOWEVER, IF THE SUBTROPICAL RIDGE (STR) TO THE WEST-NORTHWEST DOES NOT RETREAT WESTWARD AND TOWARD THE SOUTH CHINA SEA, TY 04W MAY YET AGAIN FIND ITSELF WITHIN A COMPETING STEERING ENVIRONMENT. AS SUCH, THE STR WOULD PROVIDE A WESTWARD COMPONENT, WHILE THE EXTENSION OF THE NER TO THE SOUTHEAST WOULD STEER THE SYSTEM NORTHWARD AND TOWARDS RECURVATURE. THEREFORE, LONG-TERM TRACK FORECAST IS ASSESSED WITH LOW CONFIDENCE, BUT IS LAID CLOSE TO THE MULTI-MODEL CONSENSUS GUIDANCE. REGARDING INTENSITY, THE OFFICIAL FORECAST IS ALIGNED CLOSELY WITH THE HAFS SOLUTION AND IS SET SLIGHTLY ABOVE THE MULTI-MODEL MEAN, WITH MEDIUM CONFIDENCE. THE HAFS PROJECTION OF A 120-125 KTS PEAK AT TAU 48 IS CONSISTENT WITH THE OFFICIAL JTWC FORECAST. GLOBAL DETERMINISTIC AND STATISTICAL-DYNAMICAL MODELS STILL OFFER A MORE CONSERVATIVE PEAK INTENSITY IN THE 100-115 KTS RANGE. SEVERAL RAPID INTENSIFICATION AIDS INDICATE THE POTENTIAL FOR A MAXIMUM INTENSITY REACHING 140 KTS. FORECAST CONFIDENCE: TRACK 00-72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 00-72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN