WDPN31 PGTW 311500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 26W (NALGAE) WARNING NR 019// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 18.0N 116.4E INITIAL INTENSITY: 65 KTS GEOGRAPHIC REFERENCE: 334 NM NORTHWEST OF MANILA, PHILIPPINES MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 07 KTS SIGNIFICANT WAVE HEIGHT: 30 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: TYPHOON 26W (NALGAE) HAS CONTINUED TO INTENSIFY AND BECOME SLIGHTLY BETTER ORGANIZED OVER THE PAST 12 HOURS UNDER FAVORABLE ENVIRONMENTAL CONDITIONS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS IMPROVED CONVECTIVE BANDING OVER THE SOUTHERN AND WESTERN SEMICIRCLES, NOW BEGINNING TO WRAP AROUND THE EASTERN PERIPHERY OF A LARGE BANDING EYE FEATURE. ANIMATED WATER VAPOR IMAGERY DEPICTS A MORE FAVORABLE UPPER LEVEL PATTERN, AS MODERATE POLEWARD OUTFLOW STREAMS AWAY FROM THE SYSTEM, OUTWARD TOWARD THE NORTHEAST. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE EIR IMAGERY AND FALLS WITHIN CLOSE PROXIMITY TO AGENCY FIX POSITIONS. AN EARLIER 310558Z AMSR2 WINDSPEED IMAGE SHOWS A SWATH OF 60-65 KNOT WINDS OVER THE WESTERN SEMICIRCLE WITH WEAKER WINDS OVER THE EASTERN SEMICIRCLE. THE INITIAL INTENSITY OF 65 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE AMSR2 WINDSPEED IMAGE, AND PGTW, RJTD DVORAK INTENSITY ESTIMATES ALONG WITH A COMBINATION OF OBJECTIVE DVORAK INTENSITY ESTIMATES. ENVIRONMENTAL CONDITIONS ARE GENERALLY FAVORABLE, CHARACTERIZED BY LOW (10-15 KNOTS), WARM (28-29C) SEA SURFACE TEMPERATURES (SSTS) AND MODERATE RADIAL OUTFLOW AND A DEVELOPING FAVORABLE POLEWARD OUTFLOW CHANNEL. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) CENTERED TO THE EAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.0 - 65 KTS CIMSS SATCON: 72 KTS AT 311052Z CIMSS ADT: 59 KTS AT 311140Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 10-15 KTS SST: 28-29 CELSIUS OUTFLOW: MODERATE RADIAL OTHER FACTORS: MODERATE POLEWARD OUTFLOW. ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH INITIAL WIND RADII: LOW 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: OVER THE NEXT 12 HOURS TYPHOON 26W WILL CONTINUE TO TRACK NORTH-NORTHWEST ALONG THE WESTERN SIDE OF THE STEERING RIDGE TO THE EAST, WHICH IS ORIENTED NORTH-SOUTH. ADDITIONALLY, 26W IS EXPECTED TO STRENGTHEN TO A PEAK INTENSITY OF 70 KNOTS, AS A UPPER-LEVEL POINT SOURCE IS ANTICIPATED TO DEVELOP ALOFT ALONG WITH INCREASED POLEWARD OUTFLOW. BY TAU 24, THE SYSTEM WILL MAINTAIN TYPHOON STRENGTH WHILE TURNING TOWARD THE NORTHWEST, AS THE DEEP-LAYER SUBTROPICAL RIDGE (STR) CENTERED TO THE EAST BEGINS TO BUILD WESTWARD. HOWEVER, AFTER TAU 36, THE SYSTEM WILL BE IMPACTED BY COOLING SEA SURFACE TEMPERATURES (SSTS), DRY AIR ENTRAINMENT, AND REDUCED OUTFLOW WHICH WILL LEAD TO A STEADY WEAKENING TREND THROUGH TAU 120. FURTHERMORE, THE STEERING PATTERN EVOLVES SHIFTS AGAIN, AS THE STR TO THE EAST BUILDS FURTHER WESTWARD, ALONG WITH LOWER-LEVEL FLOW OUT OF THE NORTH-NORTHEAST. THESE STEERING FACTORS WILL GRADUALLY TURN 26W TO THE WEST AND THEN SOUTHWEST. THE SYSTEM IS EXPECTED TO DISSIPATE OVER HAINAN ISLAND BY TAU 120. MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE REMAINS IN FAIR AGREEMENT, WITH THE PRIMARY OUTLIERS BEING THE UKMO TRACKER ON THE EASTERN EDGE OF THE GUIDANCE ENVELOPE AND THE HWRF ON THE WESTERN EDGE. THE REMAINDER OF THE TRACKERS ARE TIGHTLY GROUPED IN AN ENVELOPE WHICH GRADUALLY EXPANDS TO 150NM AT TAU 120. THE JTWC TRACK FORECAST REMAINS CONSISTENT WITH THE PREVIOUS FORECAST, AND LIES CLOSE TO THE MULTI-MODEL CONSENSUS MEAN THROUGH THE FORECAST PERIOD WITH MEDIUM CONFIDENCE. THE RELIABLE INTENSITY GUIDANCE IS IN OVERALL GOOD AGREEMENT. AFTER TAU 24 ALL INTENSITY GUIDANCE INDICATES A DECREASE IN INTENSITY THROUGH THE END OF THE FORECAST. THE JTWC INTENSITY FORECAST REMAINS JUST ABOVE THE MULTI-MODEL CONSENSUS THROUGH TAU 24 AND FOLLOWS CLOSE TO THE MULTI-MODEL CONSENSUS THROUGH TAU 120. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN