MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 18W (PHANFONE) WARNING NR 14// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 18W (PHANFONE), LOCATED APPROXIMATELY 343 NM SOUTH- SOUTHWEST OF IWO TO, HAS TRACKED WEST-NORTHWESTWARD AT 14 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL (MSI) AND ENHANCED INFRARED (EIR) SATELLITE IMAGERY REVEALS TY 19W HAS STARTED TO RAPIDLY INTENSIFY AS A SMALL EYE FEATURE HAS DEVELOPED WHILE CONVECTIVE BANDING HAS INCREASED IN ALL QUADRANTS. A 012218Z SSMIS MICROWAVE IMAGE ADDITIONALLY DEPICTS A SMALL (APPROXIMATELY 25 NM) EYEWALL FEATURE WITH MULTIPLE BROKEN CONVECTIVE BANDS IN THE OUTER PERIPHERIES. THE INITIAL POSITION IS BASED ON THE SMALL EYE FEATURE OBSERVED IN THE MSI AND EIR ANIMATION WITH HIGH CONFIDENCE. THE INITIAL INTENSITY HAS BEEN GREATLY INCREASED TO 105 KNOTS WHICH IS BASED ON SUBJECTIVE DVORAK INTENSITY ESTIMATES THAT HAVE RAPIDLY INCREASED TO 115 KNOTS OVER THE PAST SIX HOURS WHILE THE OBJECTIVE INTENSITY ESTIMATES RANGE FROM 65 TO 80 KNOTS. UPPER-LEVEL ANALYSIS INDICATES THE SYSTEM IS LOCATED IN A FAVORABLE ENVIRONMENT WITH LOW VERTICAL WIND SHEAR (VWS) AND GOOD DUAL CHANNEL OUTFLOW WHICH IS BEING ENHANCED BY THE MID-LATITUDE WESTERLIES TO THE NORTH. TY 18W IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR). 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING BULLETIN ALTHOUGH THE INTENSITY FORECAST HAS BEEN INCREASED DUE TO ONSET OF RECENT RAPID INTENSIFICATION EVENT. B. TY 18W WILL CONTINUE TO TRACK TO THE NORTHWEST OVER THE NEXT 48 HOURS AS THE SYSTEM PROCEEDS ALONG THE SOUTHWESTERN PERIPHERY OF THE STR. AN UPPER LEVEL TROUGH, WHICH IS CURRENTLY ANALYZED OVER EASTERN CHINA, IS EXPECTED TO PROPAGATE TO THE EAST WHICH WILL MODIFY AND BREAK THE RIDGE AXIS ALLOWING THE SYSTEM TO TRACK MORE POLEWARD BETWEEN TAU 48 TO 72. THE SYSTEM IS EXPECTED TO REACH A MAXIMUM INTENSITY OF 130 KNOTS BY TAU 36 AS THE FAVORABLE UPPER LEVEL ENVIRONMENT AND OCEAN HEAT CONTENT REACH A PEAK NEAR THIS TIME FRAME. OVERALL, NUMERIC MODEL GUIDANCE REMAINS IN GOOD AGREEMENT THROUGH TAU 72 HAVING ONLY A 140 NM SPREAD WITH THE EXCEPTION OF ECMWF, WHICH REMAINS THE FAR WESTERN MOST OUTLIER. C. IN THE EXTENDED FORECAST, THE SYSTEM IS EXPECTED TO ROUND THE RIDGE AXIS AND ACCELERATE NORTHEASTWARD, WEAKENING AS THE SYSTEM ENCOUNTERS THE MID-LATITUDE WESTERLIES AND BEGINS EXTRATROPICAL TRANSITION (ETT) AFTER TAU 96. MODELS CONTINUE TO DEPICT A RECURVE SCENARIO SOUTH OF THE HONSHU, WITH THE SYSTEM COMPLETING ETT BY TAU 120 AS IT BECOMES EMBEDDED IN THE BAROCLINIC ZONE AND BECOMES A STORM-FORCE LOW. LOW CONFIDENCE REMAINS IN THE FORECAST TRACK, WHICH IS CLOSE TO THE MULTI-MODEL CONSENSUS AS MODELS CONTINUE DISAGREE ON THE EXTENT OF RECURVATURE AND HOW THE STR MODIFIES IN RESPONSE TO THE AFOREMENTIONED TROUGH.// NNNN NNNN