WDPN31 PGTW 030900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 14W (KOINU) WARNING NR 016// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 21.1N 124.9E INITIAL INTENSITY: 100 KTS GEOGRAPHIC REFERENCE: 305 NM SOUTHEAST OF TAIPEI, TAIWAN MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 06 KTS SIGNIFICANT WAVE HEIGHT: 35 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY CONTINUES TO SHOW EVIDENCE OF SPIRAL BANDING WRAPPING INTO A RAGGED EYE, WITH DEEP CONVECTION PERSISTING IN THE SOUTHERN SEMICIRCLE. GRADUALLY WARMING INFRARED BRIGHTNESS TEMPERATURES IN THE MOST ROBUST CONVECTIVE AREAS SUGGESTS A SLIGHT DEGRADATION IN CONVECTION HAS OCCURRED OVER THE LAST SIX HOURS. OVERALL, THE SYSTEM HAS WEAKENED SLIGHTLY DUE TO THE UNREMITTING AND MOSTLY MID-LEVEL EAST-SOUTHEASTERLY VERTICAL WIND SHEAR (VWS) AND DRY AIR ENTRAINMENT IN THE EASTERN PERIPHERY OF THE SYSTEM. A 030505Z AMSR2 36GHZ MICROWAVE IMAGE CAPTURED A CLOSED AND WELL-DEFINED MICROWAVE EYE OF 25NM DIAMETER. TANGENTIALLY AND FURTHER EVIDENCING THE AFOREMENTIONED VWS AND DRY AIR ENTRAINMENT, A 030509Z ATMS 88.2 GHZ MICROWAVE IMAGE REFLECTS THE NORTHERN BOUNDARY OF THE MID TO UPPER LEVEL CIRCULATION STRUGGLING TO CLOSE OFF AND FORM AN EYE. OF RELATED NOTE, CIMSS M-PERC PROBABILITY FOR EYEWALL REPLACEMENT CYCLE (ERC) ONSET SPIKED TO 60 PERCENT NEAR 020800Z AND LATER, FROM 030000Z TO 030600Z, SHOWED EVIDENCE OF TIGHTENING RING SCORES, AS IS OBSERVED WHEN AN ERC OCCURS. THOUGH AVAILABLE MICROWAVE IMAGERY DOES SHOW AN ERC TO HAVE OCCURRED, A LACK OF MICROWAVE DATA OR THE PROMINENT VWS MAY HAVE DISTORTED THE ANALYSIS IF AN ERC HAD OCCURRED. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A 030600Z HM9 AHI 1KM VISIBLE IMAGE AND EXTRAPOLATION OF A 030505Z AMSR2 36GHZ MICROWAVE IMAGE. THE INITIAL INTENSITY OF 100 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON SUBJECTIVE INTENSITY ESTIMATES FROM PGTW, RJTD, AND KNES, AS WELL AS CIMSS OBJECTIVE INTENSITY ESTIMATES LISTED BELOW. OF NOTE, THE FINAL-T NUMBERS FOR PGTW, RJTD, AND KNES ARE ALL 1 FULL T-NUMBER OR GREATER LOWER THAN THE REPORTED CURRENT INTENSITY, CAPTURING THE EVIDENT FALLING INTENSITY OF THE SYSTEM. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR) POSITIONED TO THE EAST AND NORTHEAST WITH A BREAK TO THE NORTH. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T6.0 - 115 KTS RJTD: T6.0 - 115 KTS KNES: T5.5 - 102 KTS CIMSS SATCON: 106 KTS AT 030417Z CIMSS ADT: 109 KTS AT 030600Z CIMSS AIDT: 100 KTS AT 030600Z CIMSS DMINT: 103 KTS AT 030600Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 20-25 KTS SST: 29-30 CELSIUS OUTFLOW: STRONG EQUATORWARD OTHER FACTORS: DRY AIR ENTRAINMENT 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: TYPHOON (TY) 14W IS FORECAST TO TRACK NORTHWESTWARD ALONG THE SOUTHWESTERN PERIPHERY OF THE STR THROUGH TAU 12 TOWARD A BREAK IN THE STR ASSOCIATED WITH A MIDLATITUDE SHORTWAVE TROUGH. AFTER TAU 12, THE TROUGH WILL PROPAGATE EASTWARD ALLOWING THE STR TO REBUILD TO THE NORTH AND EXTEND FURTHER WEST, WHICH WILL TURN THE SYSTEM ON A WESTWARD TRAJECTORY THROUGH TAU 120. TY 14W IS FORECAST TO WEAKEN STEADILY THROUGH THE FORECAST INTERVAL DUE TO THE PERSISTENT VWS AS IT APPROACHES AND TRACKS OVER SOUTHERN TAIWAN WITH FURTHER WEAKENING AS IT TRACKS OVER THE SOUTH CHINA SEA, TAIWAN STRAIT REGION. MODEL DISCUSSION: GLOBAL NUMERICAL MODELS ARE IN EXCEPTIONAL AGREEMENT THAT TY 14W WILL CONTINUE TO TRACK NORTHWEST THROUGH TAU 12 AND THEREAFTER TRACK WESTWARD THROUGH TAU 120. DETERMINISTIC GUIDANCE SUGGESTS TY 14W WILL PASS OVER OR NEAR SOUTHERN TAIWAN BETWEEN TAU 36 AND TAU 48, AND CONTINUE WESTWARD THROUGH TAU 72. GLOBAL ENSEMBLE AND DETERMINISTIC SOLUTIONS SHOW TRACK UNCERTAINTY BEGINNING AROUND TAU 72, WITH A TRACK EITHER INTO SOUTHERN CHINA OR THE SOUTH CHINA SEA. A 107NM CROSS-TRACK SPREAD AT TAU 72 LENDS SOME UNCERTAINTY TO BOTH TRACK AND INTENSITY. CONSIDERING THE AFOREMENTIONED, THE TRACK AND INTENSITY FORECAST CONFIDENCE THROUGH TAU 72 IS MEDIUM, AND LOW THEREAFTER. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN