WDPN31 PGTW 291500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W (HINNAMNOR) WARNING NR 006// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 27.3N 141.3E INITIAL INTENSITY: 100 KTS GEOGRAPHIC REFERENCE: 724 NM EAST OF KADENA AB, OKINAWA MOVEMENT PAST 6 HOURS: WESTWARD AT 17 KTS SIGNIFICANT WAVE HEIGHT: 29 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: TY 12W HAS RAPIDLY INTENSIFIED (50 KNOTS) FROM 50 KNOTS AT 281200Z TO 100 KNOTS AT 291200Z. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A COMPACT, 115NM DIAMETER CENTRAL DENSE OVERCAST FEATURE WITH A 5NM PINHOLE EYE AND SPIRAL BANDING OVER THE EASTERN SEMICIRCLE. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EIR IMAGERY. A 290912Z SSMIS 91GHZ MICROWAVE IMAGE REVEALS A SYMMETRIC EYEWALL SURROUNDING A SMALL MICROWAVE EYE FEATURE. TY 12W PASSED ABOUT 17NM NORTH OF CHICHIJIMA AT 290900Z, WHICH REPORTED MAXIMUM SUSTAINED SURFACE WINDS OF 61 KNOTS (10-MINUTE AVERAGE) WITH MINIMUM SLP OF 982.5MB. THERE WERE, HOWEVER, UNOFFICIAL REPORTS OF MAXIMUM WIND GUSTS AS HIGH AS 94 KNOTS. THE INITIAL INTENSITY OF 100 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE PGTW DVORAK ESTIMATE. HIGH RESOLUTION HIMAWARI IMAGERY FROM 291130-291140Z INDICATED THE EYE TEMPERATURE PEAKED AT +11.1C, WHICH WOULD HAVE YIELDED A DATA-T OF T6.0 (115 KNOTS), HOWEVER, EYE TEMPERATURES HAVE SINCE COOLED AND GENERALLY HAVE SUPPORTED A DATA-T OF 5.5. ALTHOUGH ADT ESTIMATES ARE LOW DUE TO THE PINHOLE EYE AND HIMAWARI-8 VIEWING ANGLE ISSUES, THE ADT RAW T NUMBER IS ALSO AT 5.5 (102 KNOTS) AND THE 291310Z AIDT ESTIMATE HAS INCREASED TO 92 KNOTS. ENVIRONMENTAL CONDITIONS ARE HIGHLY FAVORABLE WITH RADIAL OUTFLOW, LOW VERTICAL WIND SHEAR AND VERY WARM SST VALUES. INITIAL WIND RADII BASIS: WIND RADII WERE ADJUSTED BASED ON A DETAILED ANALYSIS OF A 291121Z ASCAT-B BULLSEYE IMAGE CURRENT STEERING MECHANISM: DEEP-LAYERED EXTENSION OF THE SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTH AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T5.5 - 102 KTS RJTD: T5.0 - 90 KTS KNES: T5.0 - 90 KTS CIMSS ADT: 80 KTS AT 291310Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE VWS: 5-10 KTS SST: 30-31 CELSIUS OUTFLOW: MODERATE RADIAL ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: HIGH 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TY 12W IS FORECAST TO TRACK QUICKLY WESTWARD TO WEST-SOUTHWESTWARD OVER THE NEXT TWO DAYS AS IT TRACKS ALONG THE SOUTHERN PERIPHERY OF THE STR, TRANSITIONING FROM THE EASTERN STR TO THE WESTERN STR POSITIONED OVER THE EAST CHINA SEA. A MIDLATITUDE SHORTWAVE TROUGH IS STILL EXPECTED TO DIG OVER THE KOREAN PENINSULA NEAR 311200Z, HOWEVER, THE TROUGH IS TOO FAR NORTH AND PROPAGATES NORTHEASTWARD QUICKLY WITH LITTLE IMPACT ON TY 12W'S TRACK. TY 12W IS EXPECTED TO RAPIDLY INTENSIFY OVER THE NEXT 24 TO 36 HOURS REACHING A PEAK INTENSITY OF 145 KNOTS BY TAU 36. NEAR TAU 72, TY 12W WILL ENCOUNTER A COMPETING STEERING SYNOPTIC PATTERN WITH A STR TO THE NORTHEAST AND WEST AND THE NEAR-EQUATORIAL RIDGE TO THE SOUTH, WHICH WILL ESSENTIALLY BOX THE SYSTEM IN, LEADING TO AN EXTENDED PERIOD OF SLOW, QUASI-STATIONARY MOTION. AS THE SYSTEM SLOWS, UPWELLING COOLER WATER WILL SERVE TO GRADUALLY WEAKEN THE SYSTEM THROUGH TAU 120. DUE TO THE COMPETING STEERING, THERE IS HIGH UNCERTAINTY IN THE EXACT TRACK OF THE CENTER. REGARDLESS, THE SYSTEM IS EXPECTED TO TRANSITION INTO A LARGE SYSTEM WITH A 400-500NM DIAMETER. MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT THROUGH TAU 48 WITH AN 115NM SPREAD IN SOLUTIONS AT TAU 48. AFTER TAU 48, HOWEVER, DETERMINISTIC GUIDANCE DIVERGES AND IS IN POOR AGREEMENT. ALL THE MODELS INDICATE THE SYSTEM WILL SLOW AND BECOME QUASI-STATIONARY BUT DISAGREE ON WHERE THE SYSTEM WILL STALL. THE BULK OF THE DETERMINISTIC AND PROBABILISTIC GUIDANCE (ECMWF ENSEMBLE AND GEFS) INDICATES THE SYSTEM WILL STALL SOUTH TO SOUTH-SOUTHWEST OF OKINAWA FOR AT LEAST TWO DAYS. THERE IS A HIGH PROBABILITY OF RAPID INTENSIFICATION CONTINUING OVER THE NEXT 36 HOURS WITH JTWC'S RAPID INTENSIFICATION PREDICTION AID (RIPA) TRIGGERED. ADDITIONALLY, THE 290600Z COAMPS-TC INTENSITY ENSEMBLE INDICATES HIGH PROBABILITY OF RI AT 60 TO 80 PERCENT IN THE NEXT 24 HOURS DECREASING TO 30 PERCENT OR LESS THROUGH TAU 48. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN