MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 16W (FUNG-WONG) WARNING NR 07// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 16W (FUNG-WONG), LOCATED APPROXIMATELY 222 NM NORTH-NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED NORTHWESTWARD AT 17 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) AND MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICT DEEP CONVECTIVE BANDING ACROSS THE SOUTHWESTERN SEMI-CIRCLE OF A LOW LEVEL CIRCULATION CENTER (LLCC) THAT HAS BECOME PARTIALLY OBSCURED BY DEVELOPING CONVECTION OVER THE LAST 6 HOURS. A 182318z SSMIS MICROWAVE IMAGE SHOWS DEEP CONVECTION ALONG THE SOUTHERN PERIPHERY AND FORMATIVE CONVECTIVE BANDING NORTH OF THE SYSTEM. THE CURRENT POSITION IS BASED ON THE EIR AND MSI LOOPS AND THE SSMIS MICROWAVE IMAGE WITH GOOD CONFIDENCE. THE INITIAL INTENSITY HAS INCREASED TO 40 KTS BASED ON DVORAK INTENSITY ESTIMATES AND DOTSTAR SOUNDINGS. UPPER- LEVEL ANALYSIS INDICATES A MARGINALLY CONDUCIVE ENVIRONMENT AS NORTHERLY VERTICAL WIND SHEAR (VWS) HAS INCREASED TO MODERATE LEVELS (25 TO 30 KNOTS) AND EQUATORWARD OUTFLOW REMAINS STRONG. TS FUNG-WONG IS CURRENTLY TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR) THAT IS POSITIONED TO THE NORTHEAST OF THE SYSTEM. 3. FORECAST REASONING. A. THERE HAVE BEEN NO SIGNIFICANT CHANGES TO THE FORECAST PHILOSOPHY SINCE THE LAST PROGNOSTIC REASONING. B. THROUGHOUT THE NEXT 24 HOURS, TS 16W WILL CONTINUE TO TRACK TO THE NORTHWEST, GRAZING THE NORTHERN LUZON COAST, UNDER THE INFLUENCE OF THE STR TO THE EAST. A RIDGE CURRENTLY OVER SOUTHEASTERN CHINA WILL CONTINUE TO RETROGRADE TO THE WEST AND WEAKEN, ALLOWING THE SYSTEM TO TRACK TO THE NORTH AS THE STR TO THE EAST REORIENTS. MODELS ARE IN GOOD AGREEMENT WITH A TRACK TOWARD TAIWAN THROUGH TAU 36. HOWEVER, BEYOND TAU 36, MODELS CURRENTLY DEPICT TWO SCENARIOS. THE NAVGEM, HWRF AND GFDN SOLUTIONS (THE WESTWARD GROUPING) SHOW THE SYSTEM TURNING NORTHWESTWARD INTO THE TAIWAN STRAIT AFTER MAKING LANDFALL IN TAIWAN. THE MAIN STEERING INFLUENCE IN THIS SCENARIO IS A BUILDING HIGH TRANSITING FROM CENTRAL CHINA INTO THE YELLOW SEA, WHICH FORCES THE SYSTEM WESTWARD ALONG ITS SOUTHERN PERIPHERY. THE JENS, JGSM AND GFS ENSEMBLE SOLUTIONS (THE NORTHWARD GROUPING) ALSO SHOW THE CYCLONE TRACKING THROUGH TAIWAN, BUT CONTINUING TO TRACK NORTH OF THE ISLAND INTO THE WESTERN EAST CHINA SEA. DUE TO THIS BIFURCATION IN THE FORECAST, THERE IS LOW CONFIDENCE IN THE FORECAST TRACK BEYOND TAU 48. C. IN THE EXTENDED TAUS, MODELS DEPICT THE TWO SEPARATE SCENARIOS AS MENTIONED ABOVE, WITH THE WESTWARD GROUPING RUNNING THE SYSTEM INTO CHINA NEAR SHANGHAI BEFORE THE SYSTEM TRACKS INTO THE WESTERLY JET. THE MODELS IN THIS GROUPING AGREE ON A SLIGHT BREAK IN THE PERSISTENT JET FEATURE AROUND TAU 120. HOWEVER, THE NORTHWARD MODEL GROUPING DEPICTS FUNG-WONG TURNING AROUND A WEAKER STR INTO THE WESTERLIES AROUND TAU 96 AND STARTING TO EMBED IN THE BAROCLINIC ZONE BY THE END OF THE FORECAST PERIOD. THE OFFICIAL FORECAST IS CONSISTENT WITH THE NORTHWARD GROUPING, WHICH INDICATES SLOWING TRACK SPEED IN THE LATER TAUS FOLLOWED BY A TURN TO THE NORTHEAST UNDER THE MIDLATITUDE WESTERLIES. DUE TO THE SIGNIFICANT DIFFERENCES IN THE SPEED OF THE TRACK IN THE EXTENDED TAUS, THERE IS OVERALL LOW CONFIDENCE IN THE FORECAST.// NNNN NNNN