WDPN31 PGTW 010300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 22W (GONI) WARNING NR 017// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 22W (GONI), LOCATED APPROXIMATELY 165 NM EAST-SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 15 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) REVEALS THAT THE EYE FEATURE HAS FILLED WHILE THE SYSTEM HAS BEGUN TO WEAKEN OVER THE PAST 6 HOURS. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE SPIRAL BANDS OF CONVECTION PRESENT IN THE COMPOSITE RADAR LOOP AS WELL AS A REMAINING MICROWAVE EYE FEATURE PRESENT IN A 312236Z SSMIS 91 GHZ IMAGE. THE RADAR IMAGERY REVEALS THAT THE SYSTEM CENTER IS NOW POSITIONED OVER LAND NORTHWEST OF LEGAZPI, PHILIPPINES. THE INITIAL INTENSITY OF 115 KTS IS PLACED WITH FAIR CONFIDENCE AND IS BASED ON AN RJTD DVORAK CURRENT INTENSITY ESTIMATE OF T6.0 AND IS IN AGREEMENT WITH THE APPARENT WEAKENING TREND IN THE MSI LOOP. THE ENVIRONMENT IS UNFAVORABLE DUE TO THE SYSTEM POSITION OVER LAND AND MODERATE (20-25 KTS) VERTICAL WIND SHEAR (VWS). TY GONI IS TRACKING ALONG THE SOUTHERN PERIPHERY OF A DEEP- LAYERED SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTHWEST. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. THE SYSTEM WILL CONTINUE TO TRACK OVER LAND THROUGH TAU 12. CONTINUED MODERATE VWS AND THE OVER LAND TRACK WILL LEAD TO CONTINUED WEAKENING TO 90 KTS BY THIS TIME. BY TAU 24, THE SYSTEM WILL HAVE BEGUN TO TRACK OVER THE SOUTH CHINA SEA. COOLER (27-28 CELSIUS) SST AND CONTINUED MODERATE VWS WILL LEAD TO FURTHER WEAKENING TO 70 KTS BY THIS TIME. SST IS FORECAST TO DECREASE FOR THE REMAINDER OF THE FORECAST PERIOD AFTER TAU 24, WHICH WILL OFFSET A SLIGHT DECREASE IN VWS AND LEAD TO A GRADUAL WEAKENING TO 60 KTS BY TAU 72. NUMERICAL MODEL TRACK GUIDANCE REMAINS IN TIGHT AGREEMENT WITH A MAXIMUM 208 NM SPREAD IN TRACK SOLUTIONS BY TAU 72, LENDING HIGH CONFIDENCE IN THIS INITIAL PORTION OF THE JTWC FORECAST TRACK, WHICH IS LAID NEAR THE MULTI-MODEL CONSENSUS. C. BEYOND TAU 72, TY GONI WILL TRACK GENERALLY WESTWARD UNDER THE INFLUENCE OF A STR POSITIONED TO THE NORTH AND MAKE A SECOND AND FINAL LANDFALL OVER CENTRAL VIETNAM SOUTH OF DA NANG AT TAU 96. THE SYSTEM WILL CONTINUE TO GRADUALLY WEAKEN DUE TO MODERATE (15-20 KTS) VWS AND COOLER (25-26 CELSIUS) SST AT THIS TIME. AFTER LANDFALL, THE SYSTEM WILL RAPIDLY WEAKEN DUE TO TERRAIN EFFECTS AND BY TAU 120 WILL BE REDUCED TO 30KTS. NAVGEM DIVERGES TO THE RIGHT OF THE MAIN CLUSTER OF NUMERICAL MODELS AND JGSM TO THE LEFT, THEREBY OFFSETTING EACH OTHER. IN VIEW OF THIS, THERE IS FAIR CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC TRACK FORECAST, WHICH IS LAID ALONG THE MULTI- MODEL CONSENSUS.// NNNN