Powerful 05W(GAEMI) near Super Typhoon Intensity bearing down on TAIWAN// 2321utc

JTWC IS ISSUING 6HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON 05W AND 3HOURLY SATELLITE BULETINS ON THE REMNANTS OF 04W

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TYPHOON (TY) 05W GAEMI WITH A DISTINCT PINHOLE EYE AND A LARGE REGION OF DEEP CONVECTION LOCATED TO THE SOUTH AND SOUTHWEST DUE TO MODERATE (10-15KT) VERTICAL WIND SHEAR (VWS) FROM THE NORTH, GIVING THE SYSTEM AN ASYMMETRIC APPEARANCE ON THE UPPER-LEVELS. RADAR IMAGERY INDICATES THAT THE SYSTEM IS UNDERGOING AN EYEWALL REPLACEMENT CYCLE (ERC) WITH A CONCENTRIC RING OF CONVECTION DEVELOPING AROUND THE INNER EYE. A 231433Z GMI 89GHZ IMAGE DEPICTS A MICROWAVE EYE HINTING AT THE EARLY DEVELOPMENT OF AN OUTER EYEWALL AS WELL. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED ANIMATED EIR, MICROWAVE, AND RADAR IMAGERY. THE INITIAL INTENSITY OF 120 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY AND OBJECTIVE FIXES LISTED .

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TY 05W IS FORECAST TO HAVE AN OVERALL TRACK DIRECTION TO THE NORTHWEST THROUGH THE END OF THE FORECAST PERIOD WHILE UNDER THE INFLUENCE OF THE STR TO THE EAST. HISTORICALLY, THE TOPOGRAPHY OF NORTHERN TAIWAN IS KNOWN TO CAUSE A TRACK DEFLECTION WHICH MAY CAUSE A TRACK DISCONTINUITY AROUND THE NORTHERN COAST THAT WOULD OCCUR BETWEEN TAU 12 AND 24 AND IS NOT CAPTURED IN THE FORECAST GRAPHIC. BETWEEN TAU 36-48, TY 05W WILL MAKE LANDFALL AND COME UNDER THE INFLUENCE OF SOUTHWESTERLY FLOW, TRACKING SLIGHTLY NORTH- NORTHWEST BY THE END OF THE FORECAST PERIOD. THE SYSTEM WILL REMAIN IN A HIGHLY FAVORABLE ENVIRONMENT FOR INTENSIFICATION FOR THE NEXT 12 HOURS. AFTER COMPLETING ERC WHICH WILL CAUSE A SLIGHT WEAKENING BEFORE THE SYSTEM CONTINUES TO INTENSIFY TO A PEAK OF 130KTS BY TAU 36 IN AN ENVIRONMENT OF LOW SHEAR, STRONG UPPER-LEVEL DIVERGENCE, HIGH SEA SURFACE TEMPERATURES AND OCEAN HEAT CONTENT. OUTFLOW WILL REMAIN STRONG EQUATORWARD WHILE A TUTT CELL LOCATED WEST WILL CONTINUE TO ENCOURAGE STRONG POLEWARD OUTFLOW. UPON INTERACTION WITH LAND, TY 05W WILL BEGIN WEAKENING WHILE UNDER THE INFLUENCE OF SIGNIFICANT SHEAR (20-30KTS) OVER LAND AND IN THE TAIWAN STRAIT BEFORE REACHING FULL DISSIPATION OVER LAND. THERE MAY BE VARIATIONS IN HOW RAPIDLY WEAKENING WILL OCCUR BASED ON IF AND HOW LARGE THE TRACK DEVIATIONS ARE AROUND THE NORTHERN PORTION OF TAIWAN.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN GOOD AGREEMENT THAT TY 05W WILL TRACK NORTHWEST THROUGH THE END OF THE FORECAST PERIOD PRIOR TO LANDFALL. HOWEVER, MESOSCALE MODELS HAFS-A AND HWRF DEPICT THAT THE SYSTEM WILL DEFLECT NORTHWARD UPON LANDFALL WITH TAIWAN RATHER THAN RESUME THE PREVIOUS TRACK AND HINTS AT A MORE NORTHWARD LANDFALL IN MAINLAND CHINA. THE JTWC INTENSITY GUIDANCE IS ALSO IN GOOD AGREEMENT THAT THE SYSTEM WILL INTENSIFY OVER THE NEXT 24 HOURS BEFORE CONTINUOUSLY WEAKENING TO DISSIPATION THROUGH TAU 96.