MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 18W (PHANFONE) WARNING NR 10// RMKS// 1. FOR METEOROLOGISTY. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 18W (PHANFONE), LOCATED APPROXIMATELY 503 NM SOUTH- SOUTHEAST OF IWO TO, HAS TRACKED WESTWARD AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A COLD DENSE OVERCAST (CDO) FEATURE WITH TIGHTLY-CURVED BANDING WRAPPING INTO A RAPIDLY-CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC). THE CURRENT POSITION IS BASED ON THE MSI AND A 302341Z ASCAT PASS WITH HIGH CONFIDENCE. THE INITIAL INTENSITY OF 65 KNOTS IS BASED ON MATCHING DVORAK INTENSITY FROM PGTW, KNES AND RJTD. UPPER- LEVEL ANALYSIS INDICATES THE SYSTEM IS LOCATED IN A VERY FAVORABLE ENVIRONMENT WITH LOW VERTICAL WIND SHEAR AND RADIAL OUTFLOW, SUPPORTED BY A POINT-SOURCE DIRECTLY OVER THE SYSTEM AND A TUTT CELL TO THE NORTHEAST. ADDITIONALLY, WARM SEA SURFACE TEMPERATURES IN THE AREA ARE CONDUCIVE FOR FURTHER DEVELOPMENT. TY 18W IS TRACKING ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR). 3. FORECAST REASONING. A. THE FORECAST INTENSITY HAS BEEN CHANGED DUE TO AN INCREASE IN THE INITIAL INTENSITY AND RAPID INTENSIFICATION OVER THE PAST SIX HOURS. B. TY 18W WILL CONTINUE TRACKING WESTWARD ALONG THE SOUTHERN PERIPHERY OF THE STR OVER THE NEXT 12 HOURS. A SERIES OF MIGRATORY TROUGHS PASSING OVER SOUTHERN JAPAN WILL CAUSE A BREAK IN THE STR, ALLOWING TY 18W TO TURN WEST-NORTHWESTWARD THROUGH TAU 48. UPPER- LEVEL CONDITIONS ARE EXPECTED TO IMPROVE, ALLOWING TY 18W TO FURTHER INTENSIFY AND LEADING TO A PEAK INTENSITY OF 125 KNOTS BY TAU 72. C. BY TAU 72, TY 18W IS EXPECTED TO ROUND THE RIDGE AXIS AND TURN NORTHEASTWARD ALONG THE NORTHWESTERN PERIPHERY OF A REBUILDING STR. BY TAU 96, THE SYSTEM WILL BEGIN EXTRA-TROPICAL TRANSITION AS IT INTERACTS WITH THE COLD BAROCLINIC ZONE. AVAILABLE MODEL GUIDANCE IS IN GOOD AGREEMENT IN THE NEAR TERM, BUT BIFURCATES AT THE TURN. GFS AND ECMWF TRACKERS INDICATE A MORE WESTWARD RECURVATURE IN THE VICINITY OF KADENA. NAVGEM, HWRF, JENS AND CTCX TRACKERS SHOW A SOONER RECURVATURE SOUTH OF JAPAN. DUE TO UNCERTAINTY IN THE EXTENT OF THE STEERING STR AND THE BIFURCATION IN THE LATER TAUS, THERE IS OVERALL LOW CONFIDENCE IN THE JTWC FORECAST TRACK, WHICH IS POSITIONED CLOSE TO AND FASTER THAN THE MULTI-MODEL CONSENSUS.// NNNN NNNN