WDPN31 PGTW 060900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 14W (KOINU) WARNING NR 028// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 21.7N 116.9E INITIAL INTENSITY: 100 KTS GEOGRAPHIC REFERENCE: 154 NM EAST-SOUTHEAST OF HONG KONG MOVEMENT PAST 6 HOURS: WESTWARD AT 07 KTS SIGNIFICANT WAVE HEIGHT: 30 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TYPHOON (TY) 14W RAPIDLY INTENSIFYING, TIGHTENING IN HORIZONTAL STRUCTURE AND EXPOSING A CLEAR, VERY SYMMETRIC EYE OF 10NM DIAMETER. THE HIGHLY FAVORABLE ENVIRONMENT WAS REALIZED BY TY 14W, WHICH TOOK FULL ADVANTAGE OF THE WARM SEA SURFACE TEMPERATURES (29-30 DEGREES CELSIUS) AND LOW VERTICAL WIND SHEAR (5-10KTS). A 060600Z HIMAWARI-9 ENHANCED INFRARED IMAGE SHOWED THE COOLEST CLOUD TOPS TO BE VERY SYMMETRICALLY AND TIGHTLY DISPLACED JUST 30NM OUTWARD FROM THE CENTER OF THE EYE. THE COMPACT NATURE OF THE SYSTEM CERTAINLY AIDED IN THE RAPID INTENSIFICATION PROCESS. OVERSHOOTING CLOUD TOPS PERSIST, SUGGESTING INTENSIFICATION IS ONGOING. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A 060600Z HIMAWARI-9 CIRA- PROXYVIS IMAGE SHOWING AN UNOBSCURED EYE. THE INITIAL INTENSITY OF 100 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON UNIFORM SUBJECTIVE DVORAK INTENSITY ESTIMATES AND OBJECTIVE INTENSITY ESTIMATES LISTED BELOW. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE ALONG THE NORTHERN PERIPHERY OF TY 14W. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T5.5 - 102 KTS RJTD: T5.5 - 102 KTS KNES: T5.5 - 102 KTS CIMSS SATCON: 95 KTS AT 060700Z CIMSS ADT: 92 KTS AT 060730Z CIMSS DPRINT: 109 KTS AT 060536Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE VWS: 5-10 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE RADIAL ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: MEDIUM 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE HAS BEEN A SIGNIFICANT SHIFT IN THE FORECAST INTENSITY OF TY 14W SINCE THE PREVIOUS WARNING (027). THIS IS DUE TO THE UNFORESEEN OCCURRENCE OF RAPID INTENSIFICATION SINCE 060000Z. FORECAST DISCUSSION: TY 14W IS FORECAST TO TRACK WEST THROUGH TAU 48 WITH PARTICULARLY SLOW TRACK SPEEDS (2-4 KTS) FROM TAU 12 TO TAU 48 DUE TO A SUBTROPICAL RIDGE (STR) CENTERED OVER NORTHERN VIETNAM. FOLLOWING THIS ENCOUNTER, 14W IS EXPECTED TO FOLLOW THE STEERING INFLUENCE OF THE STR AND TURN SOUTHWESTWARD FROM TAU 48 TO TAU 72 AND MAINTAIN THIS HEADING THROUGH TAU 120. CLEARLY, THE SYSTEM IS IN A HIGHLY FAVORABLE ENVIRONMENT AND THE AFOREMENTIONED COMPACT STRUCTURE SEEMS TO BE KEEPING THE DRY AIR AHEAD OF TRACK OUT OF THE SYSTEM FOR THE TIME BEING. HOWEVER, TY 14 SLOWING DOWN AFTER TAU 12 WILL CAUSE DETRIMENTAL UPWELLING TO OCCUR, WHICH IS ANTICIPATED TO WEAKEN THE SYSTEM INTENSITY STARTING AT TAU 12. THE FORECAST CONFIDENCE FROM TAU 00 TO TAU 72 FOR BOTH TRACK AND INTENSITY IS MEDIUM, AND LOW THEREAFTER. MODEL DISCUSSION: GLOBAL NUMERICAL MODEL GUIDANCE IS IN EXCEPTIONAL AGREEMENT THAT TY 14W WILL CONTINUE ON A WESTWARD TRACK THROUGH TAU 48 AND THEN GRADUALLY TURN SOUTHWESTWARD AND MAINTAIN TRACK THROUGH TAU 120. HOWEVER, THE TRACK SPEED SHOWS MODERATE UNCERTAINTY BY TAU 72 WITH AN ALONG-TRACK SPREAD OF 153NM. THE SAME UNCERTAINTY COMPOUNDS AT TAU 120, WITH AN ALONG-TRACK SPREAD OF 330NM AND A CROSS-TRACK SPREAD OF 240NM. BRIEFLY DISCUSSING THE RAPID INTENSIFICATION OCCURRENCE, THE ONLY INDICATIONS OF INTENSIFICATION PRESENTED IN THE OBJECTIVE AID INTENSITIES FOR THE PREVIOUS FORECAST WERE COAMPS-TC AND HAFS-A, EACH SUGGESTING JUST A 5 KNOT RISE IN INTENSITY. PRESENTLY, HAFS-A AND STATISTICAL-DYNAMICAL INTENSITY GUIDANCE REFLECT THE POSSIBILITY OF A 5 KNOT INCREASE BY TAU 12, ALONG WITH MULTIPLE RAPID INTENSIFICATION INDICATIONS TRIGGERED. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN