WDPN31 PGTW 150300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 28W (MELOR) WARNING NR 15// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 28W (MELOR), LOCATED APPROXIMATELY 107 NM SOUTH- SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 7 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) INDICATES THE TYPHOON IS UNDERGOING RAPID INTENSIFICATION (RI), AS THE CENTRAL CORE HAS EXPANDED AND A 14 NM DIAMETER EYE HAS APPEARED. A 142254Z SSMIS 91GHZ MICROWAVE IMAGE REVEALS AN INPRESSIVE SOLID CONVECTIVE CORE EXTENDING 45-50 NM FROM THE CENTER. THE INITIAL POSITION IS BASED ON THE MSI EYE WITH HIGH CONFIDENCE. THE INITIAL INTENSITY AT THE 150000Z SYNOPTIC TIME IS ASSESSED AT 125 KNOTS, BASED ON THE PGTW T6.5 DVORAK ESTIMATE. SUBSEQUENT ANALYSIS INDICATES THE CYCLONE FURTHER INTENSIFIED, HOWEVER, THE LATEST IMAGE SHOWS SIGNS THAT THIS PHASE MAY HAVE STALLED OR ENDED.TY 28W IS UNDER THE STEERING INFLUENCE OF A DEEP LAYERED SUBTROPICAL RIDGE (STR) TO THE NORTH. 3. FORECAST REASONING. A. THE FORECAST INTENSITIES WERE INCREASED DUE TO THE CLEAR INDICATION OF RI. THE FORECAST TRACK HAS ALSO BEEN MODIFIED AS A RESULT OF THE INTENSIFICATION, WITH TY 28W NOW EXPECTED TO TRACK FURTHER WESTWARD BEFORE TRANSITIONING TO LOW LEVEL STEERING FLOW. THE FORECAST TRACK HAS ALSO BEEN EXTENDED TO 96 HOURS. B. TY MELOR WILL CONTINUE TO TRACK GENERALLY WESTWARD TO WEST- NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE STR OVER THE NEXT 36 HOURS. AFTERWARDS, THE CYCLONE WILL TURN SOUTHWESTWARD WITH THE LOW LEVEL WIND FLOW IN THE SOUTH CHINA SEA. BASED ON SLIGHT INTENSIFICATION, NOTED IN THE SATELLITE ANALYSIS, TY 28W IS FORECAST TO REACH A PEAK OF 130 KNOTS WITHIN THE NEXT 12 HOURS BEFORE BEGINNING A DISSIPATION TREND. COLD DRY AIR ASSOCIATED WITH A STRONG CONTINENTAL COLD SURGE IN THE SOUTH CHINA SEA WILL ACCELERATE ITS DECAY AFTER TAU 36. C. TY MELOR IS FORECAST TO BECOME FULLY EMBEDDED IN THE COLD SURGE FLOW AND DISSIPATE BY TAU 96. DUE THE UNCERTAINTY IN THE TIMING OF STEERING FLOW MECHANISMS, THERE IS LOW CONFIDENCE IN THE JTWC FORECAST. // NNNN