WDPN31 PGTW 061500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 14W (KOINU) WARNING NR 029// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 21.4N 116.3E INITIAL INTENSITY: 100 KTS GEOGRAPHIC REFERENCE: 129 NM EAST-SOUTHEAST OF HONG KONG MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 06 KTS SIGNIFICANT WAVE HEIGHT: 30 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TYPHOON (TY) 14W MAINTAINING A TIGHT AND COMPACT STRUCTURE OVER THE LAST SIX HOURS, AND IS BY DEFINITION DEFINED AS A SMALL TO VERY SMALL TYPHOON WITH THE RADIUS OF OUTERMOST CLOSED ISOBAR ASSESSED AT 175NM. THE ENVIRONMENT IS FAVORABLE FOR THE SYSTEM TO MAINTAIN INTENSITY WITH WARM SEA SURFACE TEMPERATURES (29-30 DEGREES CELSIUS) AND LOW VERTICAL WIND SHEAR (5-10KTS). HOWEVER, DRY AIR (LESS THAN 50 PERCENT RELATIVE HUMIDITY) IS PRESENT IN THE PATH AHEAD. THE SMALL EYE OF 9NM DIAMETER HAS MANAGED TO CONTINUE TO CONTRACT ALONG WITH THE CONVECTIVE CANOPY ALOFT. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A 061200Z HIMAWARI-9 EIR 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 ADT: 92 KTS AT 061130Z CIMSS DPRINT: 94 KTS AT 061200Z CIMSS DMINT: 101 KTS AT 061048Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: 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 ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TY 14W IS FORECAST TO TRACK WEST WITH PARTICULARLY SLOW TRACK SPEEDS (3 KTS) THROUGH 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 WEST-SOUTHWESTWARD FROM TAU 36 TO TAU 72 AND THEN STEADY UP ON A SOUTHWESTWARD TRACK THROUGH TAU 120. SLOWING TRACK SPEED WILL LIKELY CAUSE UPWELLING OF COOLER OCEAN WATER TO OCCUR, WHICH IS ANTICIPATED TO WEAKEN THE SYSTEM INTENSITY ALONG WITH THE IMPENDING INTAKE OF THE AFOREMENTIONED DRY AIR TO THE WEST OF THE SYSTEM. MODEL DISCUSSION: WITH THE EXCEPTION OF NAVGEM AND GALWEM, GLOBAL NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT THAT TY 14W WILL CONTINUE ON A WESTWARD TRACK THROUGH TAU 36 AND THEN GRADUALLY TURN THROUGH TAU 72 WHEN IT ALIGNS ON A SOUTHWESTWARD TRACK THROUGH TAU 120. NAVGEM AND GALWEM BOTH TRACK THE SYSTEM NORTHWESTWARD THROUGH TAU 48, BEFORE TURNING SOUTHWEST AND BETTER ALIGNING WITH THE OTHER JTWC CONSENSUS MEMBERS. EXCLUDING THE ALTERNATE SOLUTIONS OFFERED BY NAVGEM AND GALWEM, THE TAU 72 CROSS-TRACK SPREAD REMAINS ROUGHLY THE SAME AS THE PREVIOUS GUIDANCE AT 90NM. THE ALONG-TRACK SPREAD WITH THE SAME PARAMETERS IS 112NM. THIS COMPOUNDS AT TAU 120, WITH AN ALONG- TRACK SPREAD OF 300NM AND A CROSS-TRACK SPREAD OF 270NM. NUMERICAL MODEL INTENSITY GUIDANCE HAS PEAKED AND SUGGESTS A DOWNTREND IN INTENSITY THROUGH TAU 120. WITH GFS AND ECMWF SOLUTIONS BEING FAIRLY CONSISTENT AND THE CLOSEST TO THE JTWC CONSENSUS, THE TRACK FORECAST CONFIDENCE IS HIGH THROUGH TAU 72 AND MEDIUM THEREAFTER. THE INTENSITY FORECAST CONFIDENCE IS MEDIUM THROUGH TAU 72 AND LOW THEREAFTER. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN