WDPN32 PGTW 160900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (RAMMASUN) WARNING NR 24// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 09W (RAMMASUN), LOCATED APPROXIMATELY 114 NM WEST- NORTHWEST OF MANILA, PHILIPPINES, HAS TRACKED NORTHWESTWARD AT 15 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) INDICATES TY 09W REMAINS SLIGHTLY DISORGANIZED AS IT TRACKS FURTHER INTO THE SOUTH CHINA SEA (SCS) WHILE THE LOW LEVEL CIRCULATION CENTER (LLCC) REMAINS TIGHTLY WRAPPED AS DEEP CONVECTIVE BANDING REMAINS ALONG THE SOUTHERN PERIPHERY. A 160321Z TRMM MICROWAVE IMAGE SHOWS THE BULK OF THE DEEP CONVECTIVE BANDING IS CONFINED TO THE SOUTHERN SEMI-CIRCLE AS THE LLCC HAS BECOME SLOPPY AND HARD TO DEFINE. UPPER LEVEL ANALYSIS SHOWS A MODERATE ENVIRONMENT AS STRONG EQUATORWARD OUTFLOW IS BEING OFFSET BY MODERATE (15 TO 20 KNOTS) NORTHEASTERLY VERTICAL WIND SHEAR (VWS). THE INITIAL POSITION IS BASED ON THE MSI LOOP ALONG WITH POSITIONAL FIXES FROM PGTW AND RJTD WITH GOOD CONFIDENCE. THE CURRENT INTENSITY HAS BEEN DECREASED TO 80 KNOTS BASED ON THE STRUCTURE OF THE SYSTEM OBSERVED IN THE AFOREMENTIONED SATELLITE IMAGERY AND A WIDE SPREAD OF DVORAK INTENSITY ESTIMATES THAT RANGE FROM 65 TO 90 KNOTS. TY RAMMASUN IS CURRENTLY TRACKING ALONG THE SOUTHERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR) ANCHORED 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 INTO THE MORE OPEN WATERS OF THE SCS, FAVORABLE UPPER LEVEL CONDITIONS AND SSTS WILL ALLOW TY 09W TO REORGANIZE AND CONTINUE TO INTENSIFY WITH THE PEAK INTENSITY OCCURRING BETWEEN TAU 36 AND TAU 48, PRIOR TO MAKING A SECOND LANDFALL ACROSS HAINAN ISLAND. THE FRICTIONAL EFFECTS OF HAINAN ISLAND WILL BEGIN A WEAKENING PROCESS, ALTHOUGH THE SYSTEM IS EXPECTED TO MAINTAIN TYPHOON STRENGTH AS THE SYSTEM CROSSES OVER THE GULF OF TONKIN AND MAKES ANOTHER LANDFALL OVER VIETNAM. C. IN THE EXTENDED TAUS, TYPHOON RAMMASUN WILL MOVE INTO NORTHERN VIETNAM AND RAPIDLY DISSIPATE DUE TO LAND INTERACTION. NUMERIC MODEL GUIDANCE REMAINS IN GOOD AGREEMENT, LENDING HIGH CONFIDENCE IN THE FORECAST TRACK WHICH IS LAID VERY CLOSE TO THE MULTI-MODEL CONSENSUS.// NNNN