WDPN33 PGTW 261500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 25W (NEOGURI) WARNING NR 033// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 31.9N 153.7E INITIAL INTENSITY: 55 KTS GEOGRAPHIC REFERENCE: 462 NM NORTH OF MINAMI TORI SHIMA MOVEMENT PAST 6 HOURS: SOUTH-SOUTHEASTWARD AT 02 KTS SIGNIFICANT WAVE HEIGHT: 18 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A MARGINALLY IMPROVED APPEARANCE OF TROPICAL STORM (TS) 25W, WITH BUILDING CONVECTION OBSCURING THE LOW-LEVEL CIRCULATION CENTER (LLCC). ADDITIONALLY, POLEWARD OUTFLOW HAS IMPROVED SIGNIFICANTLY OVER THE PAST 6 HOURS. 25W CONTINUES TO EMULATE ''THE LITTLE ENGINE THAT COULD'' AND HAS MAINTAINED ITS INTENSITY AGAINST A MARGINALLY FAVORABLE ENVIRONMENT CHARACTERIZED BY MODERATE EQUATORWARD OUTFLOW ALOFT AND LOW (5-10 KTS) VERTICAL WIND SHEAR, OFFSET BY UPWELLING CAUSED BY THE STORM'S QUASI-STATIONARY MOVEMENT. A 261119Z MTC ASCAT BULLSEYE IMAGE REVEALS THE LLCC, LENDING HIGH CONFIDENCE TO THE INITIAL POSITION. THE INITIAL INTENSITY OF 55 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK INTENSITY ESTIMATES AND OBJECTIVE INTENSITY AIDS LISTED BELOW. INITIAL WIND RADII BASIS: SAR DATA CURRENT STEERING MECHANISM: COMPETING STEERING ENVIRONMENT, WITH SUBTROPICAL RIDGES (STR) FLANKING THE SYSTEM TO THE EAST AND WEST AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T3.0 - 45 KTS RJTD: T3.5 - 55 KTS RCTP: T3.5 - 55 KTS KNES: T3.5 - 55 KTS CIMSS ADT: 37 KTS AT 261130Z CIMSS AIDT: 59 KTS AT 261130Z CIMSS D-MINT: 51 KTS AT 261042Z CIMSS D-PRINT: 49 KTS AT 261130Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 5-10 KTS SST: 27-28 CELSIUS OUTFLOW: MODERATE EQUATORWARD OTHER FACTORS: UPWELLING AND DRY AIR ENTRAINMENT ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: MEDIUM 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TS 25W REMAINS CONFINED BETWEEN TWO COMPETING SUBTROPICAL RIDGES POSITIONED TO THE EAST AND WEST OF THE STORM. NEITHER RIDGE IS DOMINATING THE STEERING ENVIRONMENT AND HAS CAUSED 25W TO REMAIN QUASI-STATIONARY OVER THE PAST 24 HOURS. THE SOUTHERN PERIPHERY OF THE EASTERN RIDGE HAS BEGUN TO BUILD, AND NOW FLANKS 25W TO THE SOUTH. 25W IS FORECAST TO BEGIN ITS NORTHEASTWARD TRACK BETWEEN TAUS 0-12, PICKING UP SPEED AS THE EASTERN STR TAKES CONTROL OF THE STEERING ENVIRONMENT. 25W IS EXPECTED TO ENTER UNDER INFLUENCE OF THE MID-LEVEL JET AT TAU 36, BEGINNING ITS EXTRATROPICAL TRANSITION (ETT) AND ACCELERATING TO THE NORTHEAST THROUGH THE END OF THE FORECAST PERIOD. ETT IS EXPECTED TO BE COMPLETE NO LATER THAN TAU 72. REGARDING INTENSITY, 25W IS FORECAST TO INTENSIFY FROM 55 KTS TO 65 KTS BETWEEN TAUS 0-12, WITH FURTHER INTENSIFICATION EXPECTED FROM TAU 36 ONWARD DUE TO JET INTERACTION. 25W IS FORECAST TO PEAK AT 80 KTS AT TAU 48, BUT A HIGHER PEAK IS POSSIBLE. 25W WILL WEAKEN AGAIN BY TAU 72, AFTER COMPLETING ETT DUE TO THE EXTREME VERTICAL WIND SHEAR AND DRY AIR. MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN STRONG AGREEMENT THROUGH THE FORECAST PERIOD, WITH ONLY MINOR VARIATIONS IN TRACK SPEED OCCURRING THROUGHOUT. AS A RESULT, THE JTWC TRACK FORECAST IS PLACED WITH HIGH CONFIDENCE. RELIABLE INTENSITY GUIDANCE IS IN POOR AGREEMENT, WITH MOST MODELS PREDICTING 25W REACHING PEAK INTENSITY AT TAU 36, HOWEVER, THE PEAK INTENSITIES RANGE FROM GFS AT 80 KTS TO HAFS AT 105 KTS. THE JTWC INTENSITY FORECAST IS PLACED LOWER THAN THE MULTI-MODEL CONSENSUS AND MESOSCALE MODELS -- IN LINE WITH GFS AND THE ECMWF ENSEMBLE -- DUE TO THE EXPECTATION THAT THE ENVIRONMENT WILL NOT BE QUITE AS CONDUCIVE AS 25W TRACKS NORTHEASTWARD AND UNDERGOES ETT. THE JTWC INTENSITY FORECAST IS PLACED WITH LOW CONFIDENCE. FORECAST CONFIDENCE: TRACK 00-72 HR: HIGH INTENSITY 00-72 HR: LOW// NNNN