WDPN32 PGTW 211500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (GAEMI) WARNING NR 008// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 16.9N 125.6E INITIAL INTENSITY: 50 KTS GEOGRAPHIC REFERENCE: 589 NM SOUTH-SOUTHWEST OF KADENA AB MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 01 KTS SIGNIFICANT WAVE HEIGHT: 20 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL STORM (TS) 05W (GAEMI) WITH A DEGRADED CONVECTIVE APPEARANCE OVER THE PAST 6 HOURS. THE PARTIALLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) IS OFFSET TO THE NORTHEAST OF THE DEEP CONVECTION AND WELL-DEFINED. BANDING FEATURES CAN BE SEEN ALONG THE WESTERN AND SOUTHERN PERIPHERIES. PROMINENT NORTHEASTERLY SHEAR IS EVIDENT WITH CONVECTION BLOWING OFF TO THE WEST-SOUTHWEST AND HAS PREVENTED THE SYSTEM FROM INTENSIFYING. 05W HAS BEEN QUASI-STATIONARY OVER THE PAST 12 HOURS IN RESPONSE TO THE COMPETING STEERING ENVIRONMENT IN PLACE. ENVIRONMENTAL ANALYSIS INDICATES THAT 05W IS IN A MARGINALLY FAVORABLE ENVIRONMENT FOR FURTHER INTENSIFICATION CHARACTERIZED BY MODERATE POLEWARD AND EQUATORWARD OUTFLOW ALOFT, 15 TO 20 KTS OF VERTICAL WIND SHEAR, AND WARM (30-31 C) SEA SURFACE TEMPERATURES. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE PARTIALLY EXPOSED AND WELL-DEFINED LLCC SEEN IN THE ANIMATED EIR. THE INITIAL INTENSITY OF 50 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE OBJECTIVE AND SUBJECTIVE INTENSITY ESTIMATES LISTED BELOW. ADDITIONALLY, A 2100944Z RCM-1 SAR WIND SPEED IMAGE SHOWS A VMAX OF 50 KTS. INITIAL WIND RADII BASIS: SAR DATA CURRENT STEERING MECHANISM: COMPETING STEERING ENVIRONMENT, WITH A SUBTROPICAL RIDGE (STR) TO THE NORTH AND A NEAR EQUATORIAL RIDGE (NER) TO THE SOUTH. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T3.0 - 45 KTS RJTD: T3.5 - 55 KTS RCTP: T3.0 - 45 KTS KNES: T3.5 - 55 KTS CIMSS SATCON: 46 KTS AT 211200Z CIMSS ADT: 49 KTS AT 211200Z CIMSS DMINT: 47 KTS AT 210916Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 15-20 KTS SST: 30-31 CELSIUS OUTFLOW: MODERATE POLEWARD AND EQUATORWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH INITIAL WIND RADII: HIGH 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TS 05W IS FORECAST TO BEGIN A NORTHWARD TURN OVER THE NEXT 12 HOURS AS THE RIDGE TO THE NORTH REORIENTS TO A NORTH-SOUTH ORIENTATION, WHICH WILL DRIVE 05W NORTH-NORTHWESTWARD THROUGH TAU 72. AFTER TAU 72, RIDGING EXTENDING OVER EASTERN CHINA WILL DEVELOP AND STEER THE SYSTEM MORE NORTHWESTWARD THROUGH THE REMAINDER OF THE FORECAST PERIOD. 05W IS CURRENTLY FORECAST TO MAKE LANDFALL ALONG THE EASTERN COAST OF CHINA JUST AFTER TAU 96. THE RI INDICATORS THAT WERE PRESENT DURING THE PREVIOUS FORECAST HAVE SINCE BEEN LOST, LENDING MORE CONFIDENCE IN THE SHORT-TERM INTENSITY FORECAST. THE VERTICAL WIND SHEAR CURRENTLY PRESENT MAY BE THE LIMITING FACTOR. 05W IS FORECAST TO STEADILY INTENSIFY OVER THE NEXT 72 HOURS TO A SLIGHTLY REDUCED PEAK OF 90 KTS NEAR ISHIKAGIJIMA. VERY WARM SEA SURFACE TEMPERATURES (SST) AND HIGH OHC VALUES WILL BE THE MAIN DRIVING FACTORS FOR THE DEVELOPMENT OF THE SYSTEM. AFTER TAU 72, 05W IS EXPECTED TO BEGIN ITS WEAKENING TREND AS IT ENTERS COOLER SSTS AND VERTICAL WIND SHEAR BEGINS TO RISE. 05W IS EXPECTED TO BE TYPHOON STRENGTH AT LANDFALL, BUT RAPIDLY DETERIORATES OVER EASTERN CHINA. MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE REMAINS IN GOOD AGREEMENT WITH A 240 NM CROSS-TRACK SPREAD AT TAU 72. GALWEM AND UKMET MAKE UP THE WESTERNMOST MEMBERS, TRACKING THE SYSTEM OVER SOUTHERN TAIWAN. GFS, AMONG OTHER MODELS, SEEM TO BE WALKING THE SYSTEM CLOSER TO NORTHERN TAIWAN OVER THE PAST FEW MODEL RUNS. THE JTWC FORECAST HAS SLIGHTLY SHIFTED TO MORE CLOSELY REPRESENT THIS. THE JTWC TRACK FORECAST IS PLACED WITH MEDIUM CONFIDENCE OVERALL. INTENSITY GUIDANCE HAS IMPROVED WITH THE LOSS OF THE RI INDICATORS. GUIDANCE AGREES THAT THE SYSTEM WILL STEADILY INTENSIFY TO A PEAK INTENSITY AROUND TAU 72, RANGING FROM 75 KTS TO AROUND 100 KTS. HAFS- A IS AN OUTLIER WITH A PEAK INTENSITY OF 115 KTS. THE JTWC INTENSITY FORECAST IS PLACED ON THE HIGHER END OF GUIDANCE WITH A PEAK OF 90 KTS. THE INTENSITY FORECAST IS PLACED WITH MEDIUM CONFIDENCE THROUGHOUT THE FORECAST PERIOD. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN