WDPN32 PGTW 110900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 25W (MAN-YI) WARNING NR 010// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 14.2N 152.3E INITIAL INTENSITY: 35 KTS GEOGRAPHIC REFERENCE: 392 NM EAST OF TINIAN MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 09 KTS SIGNIFICANT WAVE HEIGHT: 16 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL STORM (TS) 25W (MAN-YI) WITH SLOW BUT IMPROVING CONVECTIVE BANDING WRAPPING AROUND THE NORTHERN AND EASTERN QUADRANTS OF THE LOW-LEVEL CIRCULATION CENTER (LLCC), WHILE THE VERTICAL STRUCTURE HAS CONTINUED TO ALIGN OVER THE LAST FEW HOURS, OBSCURING SURFACE CENTER. PERSISTENT FLARING CONVECTION OVER THE LLCC HAS ALSO BEEN OBSERVED, AIDING IN THE EXPECTED INTENSIFICATION OF THE SYSTEM. ALTHOUGH THE OVERALL LOOK OF TS 25W HAS IMPROVED SLIGHTLY, THE WESTERN SEMICIRCLE REMAINS VOID OF SIGNIFICANT CONVECTIVE CLOUD LINES, ILLUSTRATING A SWATH OF DRY AIR WRAPPING INTO THE SOUTHERN QUADRANT FROM THE WEST. MODERATE POLEWARD AND EQUATORWARD OUTFLOW ALOFT HAS ALSO BEEN OBSERVED ON THE ANIMATED WATER VAPOR LOOP, AS A FINGER FROM THE MID-LATITUDE WESTERLIES POLEWARD AND DIVERGENT FLOW EQUATORWARD CONTINUES TO SUSTAIN THE 35 KTS SURFACE INTENSITIES THROUGHOUT THE SYSTEMS CIRCULATION. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON AN 110418Z 89 GHZ GMI PASS SHOWING SHALLOW LOW-LEVEL CLOUD LINES WRAPPING INTO THE OBSCURED LLCC. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON SUBJECTIVE AND OBJECTIVE AGENCY ESTIMATES LISTED BELOW, VARYING BETWEEN 31 KTS AND 35 KTS. THE ENVIRONMENT HAS IMPROVED OVER THE LAST 24 HOURS, WITH VERTICAL WIND SHEAR (VWS) DECREASING SLIGHTLY TO 15-20 KTS WHILE THE CORE MAINTAINS ITS MOIST CHARACTERISTICS. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE NORTH, EXTENDING WESTWARD. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.5 - 35 KTS RJTD: T2.0 - 30 KTS CIMSS ADT: 34 KTS AT 110630Z CIMSS AIDT: 34 KTS AT 110630Z CIMSS D-PRINT: 34 KTS AT 110630Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 15-20 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE POLEWARD AND EQUATORWARD ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: LOW 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THE TRACK FOR TS 25W HAS MOVED SOUTHWARD WHILE THE INTENSITY OF THE SYSTEM CONTINUES TO INCREASE AS THE ENVIRONMENT BECOMES MORE CONDUCIVE. FORECAST DISCUSSION: TS 25W IS FORECASTED TO CONTINUE TO TRACK GENERALLY WESTWARD OVER THE NEXT 36 HOURS AND THEN BEGIN ITS MOVEMENT TO THE WEST-SOUTHWEST. AFTER TAU 36, THE SYSTEM WILL CONTINUE ON ITS WEST-SOUTHWESTWARD TRACK JUST NORTH OF ROTA AND BEGIN ITS ANTICYCLONIC TRACK AROUND THE PERIPHERY OF THE SUBTROPICAL RIDGE INTO THE END OF THE FORECAST PERIOD. WITH REGARD TO INTENSITY, THE SYSTEM IS FORECASTED TO SLOWLY INTENSIFY TO 45 KTS AS PERSISTENT 15-20 KTS NORTHERLY VERTICAL WIND SHEAR (VWS) PERSISTS INTO TAU 48. AFTER TAU 48, FURTHER INTENSIFICATION IS EXPECTED AS VWS IS LIMITED TO LESS THAN 20 KTS AND THE ALIGNED VERTICAL STRUCTURE OF MAN-YI SUSTAINS A MOIST CENTRAL CORE. AFTER TAU 48, A SUPPORTIVE TROPICAL UPPER-TROPOSPHERIC TROUGH (TUTT) TO THE NORTHEAST ADDS AN ADDITIONAL UPPER-LEVEL OUTFLOW MECHANISM, AIDING IN FURTHER INTENSIFICATION TO 65 KTS BY TAU 96. AS TS 25W TRACKS WESTWARD AND AWAY FROM THE SUPPORTIVE TUTT, EXPECTED INTENSITIES ARE FORECASTED TO DECREASE TO 55 KTS BY TAU 120. MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN FAIR AGREEMENT, WITH A CROSS-TRACK SPREAD OF 128 NM BY TAU 72 AND A DIVERGENT CROSS-TRACK SPREAD OF 300 NM BY TAU 120, HOWEVER, REMAINS GENERALLY WESTWARD. ALL OF THE JTWC TRACK CONSENSUS MEMBERS SHOW THE AFOREMENTIONED WESTWARD TRACK AND BEGIN ITS ANTICYCLONIC TURN NEAR TAU 96. THE JTWC FORECAST TRACK IS PLACED WITH MEDIUM CONFIDENCE DURING THE INITIAL 72 HOURS, AND IS LOW BETWEEN TAU 72 AND TAU 120, AS THE WEST-NORTHWESTWARD TURN AROUND THE SUBTROPICAL RIDGE VARIES SLIGHTLY BETWEEN JTWC MODEL TRACK MEMBERS. THE INTENSITY MODEL GUIDANCE IS ALSO IN FAIR AGREEMENT WITH THE MAJORITY OF INTENSITY CONSENSUS MEMBERS, INDICATING SLOW INTENSIFICATION THROUGH THE FIRST 48 HOURS, THEN AN EXPECTED INCREASE BETWEEN TAU 48 AND TAU 96 WITH MORE CONDUCIVE ENVIRONMENTAL PARAMETERS. WITH THAT BEING SAID, THE COAMPS-TC ENSEMBLE INTENSITY PROBABILITY CHART HAS ALSO REFLECTED FURTHER INTENSIFICATION AFTER TAU 42, WITH A 30 PERCENT CHANCE OF MODERATE INTENSIFICATION THEREAFTER. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN