WDPN32 PGTW 120900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 16W (PODUL) WARNING NR 022// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 21.3N 126.5E INITIAL INTENSITY: 70 KTS GEOGRAPHIC REFERENCE: 320 NM SOUTH-SOUTHWEST OF KADENA AB MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 16 KTS SIGNIFICANT WAVE HEIGHT: 29 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A RAPIDLY CONSOLIDATING AND COMPACT SYSTEM. MODERATE CONVECTION WAS SEEN DEVELOPING ON THE SOUTHWESTERN SIDE OF THE LOW LEVEL CIRCULATION CENTER (LLCC) AND PUSHING UPSHEAR TO THE EASTERN SIDE OF THE CENTER, JUST PRIOR TO AND CONTINUING THROUGH THE 0600Z HOUR. THIS CONVECTION SUBSEQUENTLY WARMED AND DISSIPATED, BUT ANOTHER CONVECTIVE DEVELOPMENT CYCLE IS CURRENTLY UNDERWAY. WITH EACH SUCCESSIVE CYCLE, ANIMATED WATER VAPOR IMAGERY SHOWS GRAVITY WAVES PUSHING UPSHEAR, TO THE EAST, WHICH IN TURN IS PUSHING THE SHEAR FRONT BACK TO THE EAST. THIS HAS RESULTED IN A SPLIT IN THE UPPER-LEVEL FLOW ABOUT 200NM UPSTREAM OF THE LLCC, LEADING TO AN OVERALL REDUCTION IN OUTFLOW-LEVEL SHEAR. THE LATEST FRAMES OF MSI AND EIR SHOW THE DEVELOPMENT OF A WARM SPOT, SUGGESTING THAT AN EYE MAY SOON APPEAR. A 120512Z AMSR2 PASS REVEALED A LOW-LEVEL MICROWAVE EYE FEATURE IN THE 37GHZ BAND, WHILE THE 89GHZ BAND REVEALED A SLIGHTLY TILTED VORTEX BUT NO MICROWAVE EYE FEATURE. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON A SHORT EXTRAPOLATION OF THE MICROWAVE EYE IN THE AMSR2 IMAGE DISCUSSED ABOVE. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE, HEDGED SLIGHTLY HIGHER THAN THE AGENCY SUBJECTIVE DVORAK CURRENT INTENSITY ESTIMATES, BASED ON THE RAPIDLY IMPROVING STRUCTURE. ENVIRONMENTAL CONDITIONS ARE FAVORABLE, WITH WARM SSTS, LOW EASTERLY SHEAR AND MODERATE WESTWARD OUTFLOW ALOFT. INITIAL WIND RADII BASIS: PERSISTENCE WITH EARLIER SAR DATA. CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF AN EXTENSIVE DEEP-LAYER SUBTROPICAL RIDGE (STR) EXTENDING FROM SOUTHERN CHINA TO SOUTH OF THE ALEUTIAN ISLANDS. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.0 - 65 KTS RJTD: T4.0 - 65 KTS RCTP: T4.0 - 65 KTS KNES: T4.0 - 65 KTS CIMSS SATCON: 60 KTS AT 120600Z CIMSS ADT: 55 KTS AT 120600Z CIMSS AIDT: 47 KTS AT 120600Z CIMSS D-PRINT: 60 KTS AT 120600Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 10-15 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE WESTWARD OTHER FACTORS: WEAK EQUATORWARD OUTFLOW. 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: TYPHOON (TY) 16W IS FORECAST TO TRACK WEST-NORTHWESTWARD ALONG THE SOUTHERN PERIPHERY OF AN EXTENSIVE STR THROUGH THE FORECAST PERIOD. AS THE SYSTEM APPROACHES THE SOUTHEAST COAST OF TAIWAN, THE POTENTIAL FOR ERRATIC MOTION WILL INCREASE, TO INCLUDE RAPID DECELERATION AND TRACK DEFLECTIONS, EITHER RIGHT OR LEFT, DUE TO OROGRAPHIC FORCING. THE 12-HOUR TIME STEPS OF THE FORECAST ARE NOT SUFFICIENT TO CAPTURE THESE ERRATIC MOTIONS, AND THUS, THE TRACK CONTINUES STRAIGHT OVER THE SOUTHERN PORTION OF TAIWAN BETWEEN ROUGHLY TAU 18 AND TAU 30. SIGNIFICANT CHANGES TO THE TIMING AND LOCATION OF LANDFALL ARE TO BE EXPECTED. AFTER CROSSING TAIWAN, THE SYSTEM WILL CONTINUE TO TRACK WEST-NORTHWESTWARD, MAKING A SECOND LANDFALL ALONG THE SOUTH-CENTRAL CHINESE COASTLINE, BEFORE CONTINUING INLAND THROUGH THE REMAINDER OF THE FORECAST PERIOD. IN TERMS OF INTENSITY, ENVIRONMENTAL CONDITIONS HAVE IMPROVED SIGNIFICANTLY, PARTICULARLY IN REFERENCE TO THE DEEP-LAYER SHEAR. GLOBAL AND MESOSCALE MODELS SUGGEST THIS TREND WILL CONTINUE, WITH LOW TO MODERATE (10-20 KTS) OF EASTERLY SHEAR EXPECTED TO PERSIST THROUGH THE NEXT 24 HOURS. HOWEVER, AS DISCUSSED ABOVE, THE UPPER-LEVEL FLOW HAS SPLIT UPSTREAM OF TY 16W, LEADING TO EVEN LOWER SHEAR IN VICINITY OF THE SYSTEM. COUPLED WITH INCREASING DEEP MOISTURE AND THE FACT THAT THE SYSTEM WILL BE MOVING OVER A WEDGE OF SLIGHTLY WARMER (30-31C) WATERS AS IT APPROACHES TAIWAN, TY 16W IS VERY LIKELY TO INTENSIFY SIGNIFICANTLY PRIOR TO LANDFALL IN TAIWAN. THE FORECAST CALLS FOR A PEAK OF 85 KNOTS BY TAU 12. HOWEVER, THE ACTUAL PEAK COULD BE ABOUT 10-15 KNOTS HIGHER (95-100 KTS), OCCURRING BETWEEN TAU 12 AND LANDFALL, AS SHOWN ACROSS MULTIPLE MESOSCALE MODELS. AFTER LANDFALL, THE SYSTEM WILL RAPIDLY WEAKEN OVER THE RUGGED TERRAIN OF THE CENTRAL MOUNTAIN RANGE, LIKELY EMERGING INTO THE TAIWAN STRAIT AS A STRONG TROPICAL STORM. THE SYSTEM IS UNLIKELY TO REINTENSIFY OVER THE STRAIT, AND MAKE ITS SECOND LANDFALL AS A TROPICAL STORM, BEFORE RAPIDLY WEAKENING AND DISSIPATING OVER SOUTHERN CHINA BY THE END OF THE FORECAST PERIOD. MODEL DISCUSSION: DETERMINISTIC AND ENSEMBLE TRACK GUIDANCE IS IN STRONG AGREEMENT, WITH MINIMAL CROSS- OR ALONG-TRACK SPREAD THROUGHOUT THE FORECAST PERIOD. THE JTWC FORECAST IS POSITIONED ON THE SOUTHERN SIDE OF THE GUIDANCE ENVELOPE, CLOSE TO THE GFS, GEFS MEAN, AND ECMWF-AIFS TRACKERS. INTENSITY GUIDANCE HAS DECREASED SLIGHTLY FROM THE PREVIOUS RUN, SPECIFICALLY THE RAPID INTENSIFICATION (RI) AIDS SEEN WITH THE 00Z RUN HAVE DISAPPEARED WITH THE 06Z RUN. THE INTERPOLATED HAFS-A, HWRF AND COAMPS-TC GUIDANCE PEAK AROUND 80 KNOTS AT TAU 12, HOWEVER THE NON-INTERPOLATED MEMBERS PEAK BETWEEN 95-100 KNOTS, WHICH SEEMS VERY REASONABLE BASED ON THE CURRENT TRENDS AND EXPECTED CONDITIONS. THE PREVIOUS RUNS RI GUIDANCE ALSO PEAKED IN THIS RANGE, AND THE MOST RECENT COAMPS-TC ENSEMBLE INTENSITY PROBABILITY PRODUCT INDICATES AN APPROXIMATELY 40 PERCENT CHANCE OF RI PRIOR TO LANDFALL AND A SIMILAR PROBABILITY OF A STRONG TYPHOON (100-129 KTS) MAKING LANDFALL IN TAIWAN. FORECAST CONFIDENCE: TRACK 00-72 HR: HIGH INTENSITY 00-72 HR: MEDIUM// NNNN