WDPN31 PGTW 130300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (BEBINCA) WARNING NR 013// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 22.1N 136.9E INITIAL INTENSITY: 40 KTS GEOGRAPHIC REFERENCE: 291 NM WEST-SOUTHWEST OF IWO TO MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 12 KTS SIGNIFICANT WAVE HEIGHT: 20 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED HIMAWARI-9 VISIBLE IMAGERY OVER THE PAST SIX HOURS DEPICTS A FULLY EXPOSED NEAR SURFACE CIRCULATION WITH FRAGMENTED BANDING ALONG THE NORTHERN PERIPHERY, AS A BROAD TAIL OF DEEP MONSOONAL FLOW IS ESTABLISHING ITSELF WELL TO THE EAST AND SOUTH. A TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT) CELL TO THE WEST CONTINUES TO PUMP SUBSIDENT DRY AIR INTO THE MID-LEVEL CORE OF TS BEBINCA, WHILE ALSO INDUCING AN ESTIMATED 20 KNOT DEEP LAYER SOUTHERLY VERTICAL WIND SHEAR (VWS) ACROSS THE LLCC, ACCORDING TO THE CIMSS SHEAR ANALYSIS. POLAR ORBITING MICROWAVE DATA AVAILABILITY REMAINS SPORADIC, HOWEVER, THE INITIAL POSITION WAS PLACED WITH HIGH CONFIDENCE GIVEN THE EXPOSED LLCC. THE INTENSITY ANALYSIS IS CHALLENGING AS THE CONVECTIVE SIGNATURE MAY NOT ACCURATELY REFLECT THE SURFACE WIND FIELD. AGENCY CURRENT INTENSITY NUMBERS RANGE FROM T2.5 TO T3.5 (35 TO 55 KNOTS). IN THE ABSENCE OF AERIAL RECONNAISSANCE OR SCATTEROMETER DATA TO AID THE ANALYSIS, THE INTENSITY IS ASSESSED WITH LOW CONFIDENCE AT 40 KNOTS BASED ON THE POOR SATELLITE PRESENTATION AND AVAILABLE OBJECTIVE INTENSITY AIDS. VIGOROUS POLEWARD OUTFLOW IS ENHANCED BY THE TUTT FLOW, WHILE THE EQUATORWARD FLOW IS CONSTRAINED TO A CHANNEL ON THE EASTERN SIDE OF THE CIRCULATION. WARM SEA SURFACE TEMPERATURES OF 29-30C REMAIN FAVORABLE. INITIAL WIND RADII BASIS: CIRA MULTIPLATFORM SATELLITE WIND ANALYSIS CURRENT STEERING MECHANISM: TS BEBINCA IS TRACKING NORTHWESTWARD ALONG THE ENHANCED GRADIENT BOUNDARY BETWEEN A SUBTROPICAL RIDGE TO THE NORTHEAST AND THE BROAD UPPER LEVEL CYCLONIC TUTT FLOW. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T3.5 - 55 KTS RJTD: T2.5 - 35 KTS RCTP: T3.0 - 45 KTS KNES: T3.0 - 45 KTS CIMSS SATCON: 52 KTS AT 121400Z CIMSS ADT: 33 KTS AT 130130Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY UNFAVORABLE VWS: 10-15 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE POLEWARD OTHER FACTORS: : UNFAVORABLE ENVIRONMENT DUE TO PROXIMITY TO TUTT CELL TO THE WEST. ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: LOW INITIAL WIND RADII: LOW 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: PEAK INTENSITY WAS REVISED DOWNWARD DUE TO CONTINUED UNFAVORABLE CONDITIONS. THE FORECAST STILL CALLS FOR REINTENSIFICATION TO A TYPHOON BY TAU 48, HOWEVER AN ALTERNATE SCENARIO IS DEVELOPING IN WHICH CONTINUED TUTT INTERACTION MAY CONTINUE TO INHIBIT SIGNIFICANT RE-INTENSIFICATION THROUGHOUT THE FORECAST. FORECAST DISCUSSION: THE OVERALL FORECAST TRACK PHILOSOPHY REMAINS THE SAME. TS BEBINCA WILL CONTINUE TO TRACK ALONG THE STEERING RIDGE AND IS EXPECTED TO MAKE LANDFALL NEAR SHANGHAI, CHINA BY TAU 72. THE TRACK POSITION AND CPA RELATIVE TO OKINAWA REMAINS RELATIVELY STEADY SINCE THE PREVIOUS WARNING, HOWEVER THERE IS HIGH ALONG TRACK UNCERTAINTY GIVEN THE CHANGING STEERING LEVELS. THE TUTT CELL FLOW IS CURRENTLY HELPING TO ENHANCE THE STEEERING, RESULTING IN A FASTER THAN NORMAL MOTION. HOWEVER, FORWARD SPEEDS SHOULD SLOW ONCE THE TUTT CELL MOVES FARTHER WEST LATER IN THE FORECAST. THE INTENSITY FORECAST REMAINS VERY CHALLENGING DUE TO UNCERTAINTY IN THE EVOLUTION OF THE TUTT CELL, AND ALSO DUE TO LIMITED GUIDANCE AVAILABLE AT THIS TIME. TS 14W IS EXPECTED TO GRADUALLY RECOVER AS THE TUTT CELL MOVES WEST. ADDITIONALLY WARMER WATERS NEAR THE RYUKUS WILL ALSO AID IN RE-INTENSIFICATION AS THE SYSTEM MOVES THROUGH THE ISLAND CHAIN. MODEL DISCUSSION: MULTI-MODEL CONSENSUS IS IN GOOD AGREEMENT IN THE CROSS-TRACK SPREAD, INDICATING PASSAGE NORTH OF OKINAWA. BOTH THE 30 GEFS MEMBER ENSEMBLE AND THE 50 MEMBER ECENS ENSEMBLE NOW KEEP TS BEBINCA TO THE NORTH OF THE ISLAND, INCREASING THE CONFIDENCE IN THE SHORT-TERM TRACK FORECAST. REGARDLESS, OKINAWA REMAINS WITHIN THE SWATH OF POTENTIAL 35 KNOT WINDS. THE UKMET MODEL AND THE MOGREPS ENSEMBLE MEAN ARE SHOWING POTENTIAL FOR A RECURVE SCENARIO, WITH A POSSIBLE TRACK TOWARDS SOUTH KOREA IN THE EXTENDED TERM, HOWEVER, THIS IS NOT SEEN IN THE OTHER GUIDANCE. MODEL INTENSITY GUIDANCE GENERALLY AGREES THAT TS 14W HAS A WINDOW FOR REINTENSIFICATION AS IT TRACKS THROUGH THE RYUKUS, WITH COAMPS-TC REMAINING VERY AGGRESSIVE. THE FORECAST WAS SET AT THE LOW END OF THE COAMPS-TC ENVELOPE, AND NEAR THE GFS SOLUTION. THE PEAK INTENSITY WAS LOWERED BUT MAINTAINS A TYPHOON AT LANDFALL. DUE TO THE NUMEROUS FACTORS DISCUSSED, OVERALL INTENSITY CONFIDENCE ESTIMATES ARE LOW, WHILE TRACK CONFIDENCE IS MODERATE. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: LOW INTENSITY 72-120 HR: LOW// NNNN