WDPN31 PGTW 261500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 25W (SURIGAE) WARNING NR 014// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 23.3N 126.9E INITIAL INTENSITY: 70 KTS GEOGRAPHIC REFERENCE: 198 NM SOUTH-SOUTHWEST OF KADENA AB MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 04 KTS SIGNIFICANT WAVE HEIGHT: 25 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A SLOW-MOVING SYSTEM, ATTEMPTING TO CLEAR OUT AN EYE FEATURE, THOUGH AS OF YET, NOT SUCCEEDING IN THIS ENDEAVOR. THE MOST RECENT FRAMES OF EIR HOWEVER, AT 1320Z SHOW A NASCENT PINHOLE EYE, BUT WHETHER THIS WILL BE ANOTHER IN A STRING OF FAILED ATTEMPTS, OR THE REAL DEAL, IS YET TO BE DETERMINED. THE SYSTEM HAS SLOWED TO 4 KNOTS; TROCHOIDAL WOBBLING OF THE INNER CORE HAS RESULTED IN ERRATIC SHORT- TERM TRACK MOTION AS CONVECTIVE ORGANIZATION PROCEEDS. A 261141Z ASCAT-B PASS DEMONSTRATES THAT WHILE THE CENTRAL DENSE OVERCAST (CDO) AND CONVECTIVE CANOPY REMAIN ASYMMETRIC, THE UNDERLYING LOW-LEVEL CIRCULATION IS HIGHLY SYMMETRIC AND WELL DEFINED. MAXIMUM SAMPLED SCATTEROMETER WINDS WERE 55 KNOTS; HOWEVER, GIVEN THE EXTREMELY COMPACT INNER CORE AND TYPICAL ASCAT RAIN ATTENUATION/RESOLUTION LIMITATIONS AT HIGHER WIND SPEEDS, OPERATIONAL SURFACE WINDS ARE ASSESSED TO BE 10-15 KNOTS STRONGER. THE INNER CORE REMAINS BEYOND JMA RADAR COVERAGE, THOUGH THE NORTHERN ARC OF THE DEVELOPING EYEWALL REMAINS DETECTABLE. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE ASCAT-B FIX. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE, BIASED HIGHER THAN THE BULK OF SUBJECTIVE AND AUTOMATED ESTIMATES IN DEFERENCE TO SCATTEROMETER DATA. PERSISTENCE AMONG SUBJECTIVE AND OBJECTIVE FIXES OVER THE PAST SIX HOURS SUGGESTS THE SYSTEM HAS ENTERED A TEMPORARY PLATEAU IN INTENSIFICATION PENDING STABLE EYEWALL DEVELOPMENT. ENVIRONMENTAL CONDITIONS REMAIN HIGHLY FAVORABLE, CHARACTERIZED BY MINIMAL DEEP- LAYER SHEAR, HIGH SSTS (29-30C), HIGH OHC, STRONG DUAL-CHANNEL OUTFLOW, AND A VERY LOW VENTILATION INDEX OF 0.004. INITIAL WIND RADII BASIS: SCATTEROMETER DATA CURRENT STEERING MECHANISM: THE SYSTEM IS AT THE RIDGE AXIS, IN A GENERALLY WEAK STEERING ENVIRONMENT. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.5 - 77 KTS RJTD: T3.5 - 55 KTS CIMSS SATCON: 57 KTS AT 261020Z CIMSS ADT: 51 KTS AT 261140Z CIMSS AIDT: 52 KTS AT 261140Z CIMSS D-PRINT: 75 KTS AT 261240Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 0-5 KTS SST: 29-30 CELSIUS OUTFLOW: STRONG DUAL-CHANNEL 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: TYPHOON (TY) 25W RESIDES ENTIRELY WITHIN A LARGE COL REGION BETWEEN AN EXPANSIVE SUBTROPICAL RIDGE (STR) TO THE EAST AND A BROAD CONTINENTAL RIDGE CENTERED OVER SOUTHWESTERN CHINA. HAVING ENTERED THIS WEAK STEERING ENVIRONMENT APPROXIMATELY SIX HOURS AGO, THE SYSTEM HAS DECELERATED MARKEDLY, DRIFTING SLOWLY NORTHWARD AT 4 KNOTS. THE STR TO THE EAST IS FORECAST TO WEAKEN AND RECEDE SOUTHWESTWARD OVER THE NEXT 12 TO 24 HOURS, ALLOWING TY 25W TO ROUND THE RIDGE AXIS, EXIT THE COL, AND INITIATE RECURVATURE TO THE NORTHEAST UNDER THE INFLUENCE OF A PROGRESSIVE, RELATIVELY WEAK MID- LATITUDE SHORTWAVE TROUGH. BEYOND TAU 36, THE STR TO THE SOUTHEAST REMAINS WEAKENED WHILE MID-LATITUDE FLOW TO THE NORTH BECOMES PREDOMINANTLY ZONAL; TY 25W WILL TRANSLATE NORTHEASTWARD ALONG THIS RELAXED STEERING GRADIENT AT 9-10 KNOTS THROUGH TAU 120. REGARDING INTENSITY: THE SYSTEM APPEARS POISED TO COMPLETE EYE FORMATION; RETENTION OF AN EYE WILL BE THE PIVOTAL FACTOR GOVERNING NEAR-TERM INTENSIFICATION. THERMODYNAMIC CONDITIONS STRONGLY FAVOR INTENSIFICATION, INCLUDING A MODERATE PROBABILITY OF RAPID INTENSIFICATION (RI) OVER THE NEXT 24 HOURS. BEYOND TAU 24, INCREASING VWS WILL BE PARTIALLY COUNTERBALANCED BY VIGOROUS POLEWARD OUTFLOW, LEADING TO A GRADUAL WEAKENING TREND THROUGH TAU 72. IN THE EXTENDED FORECAST, 25W WILL WEAKEN MORE RAPIDLY DUE TO LOWER SSTS, ELEVATED SHEAR, DRY AIR ENTRAINMENT, AND THE ONSET OF EXTRATROPICAL TRANSITION (ETT). THE SYNOPTIC PHILOSOPHY REMAINS UNCHANGED, WITH THE BIFURCATED ALTERNATIVE SCENARIO STILL VIABLE. THE GFS AND HAFS-A PERSIST AS THE PRIMARY OUTLIERS ADVANCING THIS ALTERNATIVE, CONTRIBUTING TO ELEVATED FORECAST UNCERTAINTY. THE GFS SUSTAINS 25W AS A MORE INTENSE CYCLONE FOR AN EXTENDED PERIOD, WHILE SIMULTANEOUSLY ACCELERATING CYCLOGENESIS OF A SECONDARY DISTURBANCE NEAR THE MARIANAS. IN THE GFS SOLUTION, THESE COMBINED SYSTEMS REINFORCE DEVELOPMENT OF A STRONG RIDGE TO THE NORTH AND EAST OF 25W, EFFECTIVELY BLOCKING POLEWARD PROGRESSION. ADDITIONALLY, THE GFS DEPICTS A WEAKER, LESS DYNAMIC TROUGH THAT FAILS TO EXTEND SUFFICIENTLY EQUATORWARD TO INDUCE RECURVATURE. MODEL DISCUSSION: TRACK GUIDANCE WITHIN THE 120-HOUR FORECAST WINDOW EXHIBITS PRONOUNCED DISPERSION EXCEEDING 1200 NM, RANGING FROM SOUTHEAST OF OKINAWA TO NORTHEAST OF TOKYO, WITH SPREAD IN POST-TAU 120 TIMEFRAME EXCEEDING 2000 NM. MULTI-MODEL ENSEMBLES DEPICT EXTREME INTRA-MEMBER VARIANCE; THE ENSEMBLE SPREAD AT TAU 120 BOUNDS AN ENVELOPE SPANNING FROM LUZON TO SHEMYA ISLAND, REPRESENTING HISTORICALLY ANOMALOUS TRACK DISPERSION FOR A WEST PACIFIC RECURVING TYPHOON. THE GUIDANCE ENVELOPE REMAINS TIGHT THROUGH TAU 24 BEFORE ALONG-TRACK DISPERSION ACCELERATES RAPIDLY. GFS ARRESTS FORWARD MOTION AT TAU 48 NEAR THE LATITUDE OF OKINAWA BEFORE COMMENCING A RETROGRADE SOUTHWESTWARD DRIFT THROUGH TAU 120. NAVGEM HAS SHIFTED NORTHEASTWARD BUT REMAINS AN ALONG-TRACK SLOW OUTLIER. NOTEWORTHILY, THE 1200Z ECMWF HAS ADJUSTED APPROXIMATELY 600 NM EQUATORWARD COMPARED TO ITS 0600Z RUN, ALIGNING CLOSER IN FORWARD SPEED TO NAVGEM AND THE MULTI-MODEL CONSENSUS (CONW). AMONG THE REMAINING GUIDANCE, UKMET ENSEMBLE, ECEPS, THE AI CONSENSUS (AICN), AND EC-AIFS ARE TIGHTLY CLUSTERED APPROXIMATELY 100 NM NORTHEAST OF THE JTWC FORECAST AT TAU 120. GOOGLE DEEPMIND, EXPERIMENTAL DEEPMIND, AND WINDBORNE AI RESIDE 200-400 NM FURTHER DOWNSTREAM (FASTER). THE JTWC TRACK CLOSELY MIRRORS AICN THROUGH TAU 48, THEN REFLECTS A MORE CONSERVATIVE FORWARD SPEED, PLACED NEAR THE MIDPOINT BETWEEN AICN AND CONW AT TAU 120. INTENSITY GUIDANCE DEMONSTRATES SOLID CONSENSUS FOR AN INITIAL PEAK AT TAU 24, FOLLOWED BY GRADUAL WEAKENING. MULTIPLE RI AIDS REMAIN TRIGGERED, PROJECTING PEAKS UP TO 110 KNOTS (CTCX PEAKS AT 105 KTS; HAFS-A AT 95 KTS). CIMSS AI-RI GUIDANCE INDICATES A 50 PERCENT PROBABILITY OF RI25 AND A 53 PERCENT PROBABILITY OF RI35. THE JTWC FORECAST PREDICTS A 25-KNOT INTENSIFICATION OVER 24 HOURS (MATCHING RI25 THRESHOLDS), JUST BELOW THE STANDARD 30-KNOT RI BENCHMARK; HOWEVER, HIGHER PEAK WINDS REMAIN A STRONG PROBABILITY GIVEN THE ENVIRONMENT. DOWNSTREAM INTENSITY GENERALLY FOLLOWS THE MULTI-MODEL CONSENSUS MEAN. FORECAST CONFIDENCE: TRACK 00-72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 00-72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN