MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (RAMMASUN) WARNING NR 23// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 09W (RAMMASUN), LOCATED APPROXIMATELY 47 NM WEST-SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 16 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY INDICATES TY 09W LOST ITS EYE FEATURE OVER THE PAST SIX HOURS WHILE TRACKING ACROSS SOUTHERN LUZON, HOWEVER, TIGHTLY CURVED BANDING REMAINS. THE LOW LEVEL CIRCULATION CENTER (LLCC) HAS NOW TRACKED OFF THE WESTERN COAST OF LUZON AND INTO THE SOUTH CHINA SEA (SCS). THE INITIAL POSITION IS BASED ON THE EIR, AND SUPPORTED BY A 152148Z SSMIS 91GHZ MICROWAVE IMAGE. THE INITIAL INTENSITY IS ASSESSED AT 90 KNOTS BASED ON A RANGE OF DVORAK CURRENT INTENSITY ESTIMATES FROM PGTW AND RJTD, AND TAKES INTO ACCOUNT THE SLIGHT DEGRADATION OF THE CONVECTIVE STRUCTURE. UPPER-LEVEL ANALYSIS INDICATES NORTHEASTERLY VERTICAL WIND SHEAR HAS INCREASED SLIGHTLY TO 10-15 KNOTS, HOWEVER ROBUST OUTFLOW REMAINS IN PLACE. SEA SURFACE TEMPERATURES (SSTS) IN THE SCS ARE SUPPORTIVE OF FURTHER INTENSIFICATION. THE CYCLONE IS CURRENTLY TRACKING ALONG THE SOUTHERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR) TO THE NORTH. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING BULLETIN. B. TY 09W IS FORECAST TO REMAIN GENERALLY ON A WEST-NORTHWESTWARD TRACK THROUGHOUT ITS LIFESPAN. AS THE SYSTEM TRACKS OVER THE OPEN WATERS OF THE SCS, FAVORABLE UPPER LEVEL CONDITIONS AND SSTS WILL ALLOW TY 09W TO REORGANIZE AND CONTINUE INTENSIFYING TO A PEAK OF 110 KNOTS BY TAU 48, PRIOR TO MAKING A SECOND LANDFALL ACROSS HAINAN ISLAND. CONDITIONS ARE FORECAST TO REMAIN FAVORABLE AS THE SYSTEM CROSSES INTO THE GULF OF TONKIN, ALLOWING TY 09W TO MAINTAIN ITS TYPHOON STATUS PRIOR TO MAKING LANDFALL OVER VIETNAM. C. IN THE EXTENDED TAUS, TYPHOON RAMMASUN WILL MOVE INTO NORTHERN VIETNAM AND RAPIDLY DISSIPATE DUE TO LAND INTERACTION. AVAILABLE DETERMINISTIC AND ENSEMBLE MODEL GUIDANCE REMAINS IN GOOD AGREEMENT, LENDING HIGH CONFIDENCE IN THE FORECAST TRACK WHICH IS LAID VERY CLOSE TO THE MULTI-MODEL CONSENSUS.// NNNN NNNN