WDPN31 PGTW 311500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 06W (NIDA) WARNING NR 09// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 06W (NIDA), LOCATED APPROXIMATELY 252 NM NORTH OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 13 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY INDICATES A SLIGHT WEAKENING TREND AS TY 06W SKIRTED THE NORTHERN COAST OF LUZON, HOWEVER, TY 06W HAS RETAINED THE BULK OF ITS DEEP CONVECTIVE BANDING STRUCTURE. A 310955Z SSMIS 91GHZ IMAGE SHOWS MULTIPLE DEEP CONVECTIVE BANDS WRAPPING TIGHTLY INTO THE CENTER. NEARBY SURFACE OBSERVATIONS FROM CALAYAN (19.3N 121.5E) AND APARRI (18.4N 121.6E) SHOWED SUSTAINED WINDS OF ONLY 24 TO 28 KNOTS WITH A MINIMUM SLP VALUE NEAR 988.3MB. THE CURRENT INTENSITY REMAINS ASSESSED AT 65 KNOTS BASED ON DVORAK CURRENT INTENSITY ESTIMATES OF T4.0 (65 KNOTS) FROM BOTH PGTW AND RJTD. TY 06W IS CURRENTLY TRANSITIONING TO THE STEERING INFLUENCE OF THE SUBTROPICAL RIDGE (STR) ENTRENCHED OVER EASTERN CHINA AND THE EAST CHINA SEA. OVERALL, ENVIRONMENTAL CONDITIONS ARE FAVORABLE WITH LOW VERTICAL WIND SHEAR, GOOD OUTFLOW AND WARM SST. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 06W IS FORECAST TO TRACK WEST-NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE DEEP STR ENTRENCHED OVER EASTERN CHINA. THE SYSTEM IS FORECAST TO TRACK NEAR HONG KONG AS IT TRACKS ALONG THE SOUTHERN PERIPHERY OF THIS STR. THE STR OVER EASTERN CHINA IS EXPECTED TO REMAIN STRONG THROUGH TAU 72 DUE TO THE PRESENCE OF A STRONG HIGH OVER MONGOLIA AND LACK OF ANY SIGNIFICANT MIDLATITUDE SHORTWAVE TROUGHS. DYNAMIC GUIDANCE REMAINS IN TIGHT AGREEMENT, THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST TRACK, WHICH IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS AND IS HIGHLY CONSISTENT WITH THE PREVIOUS FORECASTS. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO REMAIN FAVORABLE THEREFORE THE SYSTEM SHOULD INTENSIFY TO A PEAK INTENSITY OF 85 KNOTS BY TAU 24 BEFORE MAKING LANDFALL NEAR HONG KONG BY TAU 36. AFTER TAU 36, TY 06W WILL WEAKEN RAPIDLY AS IT TRACKS WESTWARD INTO CHINA AND WILL DISSIPATE BY TAU 72.//