WDPN31 PGTW 060300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 14W (KOINU) WARNING NR 027// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 21.8N 117.7E INITIAL INTENSITY: 75 KTS GEOGRAPHIC REFERENCE: 197 NM EAST OF HONG KONG MOVEMENT PAST 6 HOURS: WESTWARD AT 07 KTS SIGNIFICANT WAVE HEIGHT: 25 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: SURPRISING NEARLY EVERYONE EXCEPT THE HAFS-A, WHICH PREDICTED THIS EVENTUALITY, TYPHOON (TY) 14W (KOINU) HAS DECIDED TO REINTENSIFY AS IT TRACKS ACROSS THE FAR NORTHERN REGION OF THE SOUTH CHINA SEA. OVER THE PAST SIX HOURS, VORTICAL HOT TOWERS WITH CLOUD TOP TEMPERATURES NEAR -75C HAVE BEEN FIRING OFF ALONG THE SOUTHERN SIDE OF THE EYEWALL, THEN ROTATING UP THE EASTERN SIDE, ALLOWING FOR A SMALL 10NM EYE TO BEGIN TO CLEAR OUT. ANIMATED RADAR DATA SHOWS A STRENGTHENING EYEWALL AND SPIRAL RAIN BANDS WRAPPING INTO A VERY COMPACT INNER CORE. THE SMALL SIZE OF THE INNER CORE HAS EVIDENTLY ALLOWED THE SYSTEM TO SHIELD ITSELF FROM SIGNIFICANT DRY AIR INTRUSION, THOUGH THE RADAR AND A 052210Z SSMIS 91GHZ MICROWAVE IMAGE SHOW A WEDGE OF RELATIVELY DRY AIR MID-LEVEL AIR WRAPPING UP FROM THE SOUTH ALONG THE EASTERN PERIPHERY OF THE INNER CORE, EFFECTIVELY ISOLATING THE INNER CORE FROM THE LARGER ENVIRONMENT. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON AN OVERALL ASSESSMENT OF THE AGENCY FIXES, WHICH ARE EVALUATED AS BEING A BIT TOO HIGH, AND THE OBJECTIVE ESTIMATES INCLUDING THE DPRINT, ADT AND AIDT. THE LATEST CIMSS ANALYSIS INDICATES SHEAR REMAINS LIGHT, ABOUT 10 KNOTS OUT OF THE NORTHEAST, BUT CLEARLY NOT PENETRATING TO THE INNER SANCTUM OF THE SYSTEM. UPPER LEVEL ANALYSIS SHOWS THE SYSTEM UNDER A WEAK RIDGE ALOFT, AND IS EFFECTIVELY CUTOFF FROM ANY OUTFLOW CHANNELS, WITH OUTFLOW LIMITED TO A MESOSCALE RADIAL PATTERN. SSTS REMAIN VERY WARM, BUT OHC VALUES ARE VERY LOW WHICH WILL PROVE A HINDRANCE GOING FORWARD. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: SOUTHERN SIDE OF A SUBTROPICAL RIDGE (STR) AXIS EXTENDING FROM SOUTHERN CHINA TO EAST OF OKINAWA. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T5.0 - 90 KTS RJTD: T4.5 - 77 KTS KNES: T5.0 - 90 KTS CIMSS ADT: 67 KTS AT 052330Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 5-10 KTS SST: 28-29 CELSIUS OUTFLOW: MODERATE RADIAL ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: LOW 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: WHILE THE SYSTEM HAS OUTPERFORMED EXPECTATIONS IN TERMS OF INTENSITY, THERE HAS BEEN NO CHANGE IN THE FORECASTED TRACK AND THE SYSTEM CONTINUES TO MOVE DOWN THE PREVIOUSLY FORECASTED TRACK LINE. THE SYSTEM IS FORECAST TO TRACK WEST-SOUTHWEST FOR THE NEXT 12 HOURS, THEN SLOW DOWN WHILE TURNING MORE WESTWARD, GENERALLY IN THE DIRECTION OF HONG KONG. THE SYSTEM IS FORECAST TO SLOW DOWN TO JUST 2-3 KNOTS AFTER TAU 36 AS A SUBTROPICAL RIDGE (STR) CENTERED OVER NORTHERN VIETNAM STRENGTHENS AND BLOCKS, OR SLOWS, FURTHER WESTWARD MOVEMENT. IN TERMS OF INTENSITY, THE RECENT BURST OF INTENSIFICATION IS LIKELY TO BE SHORT-LIVED. THE ACTUAL PEAK MAY COME IN THE NEXT SIX HOURS OR SO. BUT THEN, AS THE SYSTEM SLOWS AND UPWELL COOLER WATERS TO THE SURFACE, IT WILL BEGIN TO SLOWLY WEAKEN WHILE REMAINING JUST OFF THE COAST OF SOUTHEASTERN CHINA. BY TAU 72, THE SYSTEM IS EXPECTED TO HAVE WEAKENED CONSIDERABLY UNDER THE INFLUENCE OF UPWELLING, AND THE INFLUX OF DRY CONTINENTAL AIR FLOWING SOUTH OFF SOUTHERN CHINA. AS TY WEAKENS BELOW 50 KNOTS, IT WILL COME UNDER THE STEERING INFLUENCE OF A LOW- TO MID-LEVEL ANTICYCLONE OVER CENTRAL CHINA, AND TURN SHARPLY SOUTHWESTWARD, TRACKING ROUGHLY PARALLEL TO THE CHINESE COAST. ONCE ESTABLISHED ON THE SOUTHWESTWARD TRACK, THE SYSTEM WILL ACCELERATE TOWARDS HAINAN ALONG THE LEADING EDGE OF A NORTHEAST COLD SURGE. DISSIPATION IS EXPECTED BY TAU 120, JUST SOUTH OF HAINAN BUT COULD BE EARLIER AS IT CROSSES HAINAN ISLAND. MODEL DISCUSSION: DETERMINISTIC AND ENSEMBLE TRACK GUIDANCE CONTINUES TO BE IN GOOD AGREEMENT ON THE OVERALL TRACK SCENARIO. ALL CONSENSUS MEMBERS AGREE THAT THE SYSTEM WILL TRACK GENERALLY WESTWARD, SLOW DOWN AFTER TAU 24, BECOME NEARLY QUASI-STATIONARY THROUGH TAU 48, THEN EJECT SOUTHWESTWARD. CROSS-TRACK SPREAD IS LESS THAN 100NM THROUGH TAU 48, THEN GRADUALLY INCREASES TO 300NM BY TAU 120. ALONG-TRACK SPREAD IS MINIMAL UNTIL TAU 72, THEN DRAMATICALLY INCREASES TO OVER 300NM BY TAU 120. OVERALL CONFIDENCE IN THE JTWC FORECAST IS HIGH TO TAU 72, THEN MEDIUM. INTENSITY GUIDANCE IS MIXED, WITH HAFS-A AND CTCX TRACKERS SHOWING THE SYSTEM INTENSIFYING UP TO 80-85 KNOTS BY TAU 12, FOLLOWED BY A SHARP WEAKENING TREND AND CATCHING UP WITH THE CONSENSUS AND SHIPS FORECASTS BY TAU 36. AFTER TAU 24, ALL MODELS INDICATE SHARP WEAKENING AND ALL GUIDANCE ENDS UP DISSIPATING THE SYSTEM BY TAU 120. AS MENTIONED ABOVE, IT IS POSSIBLE THE SYSTEM WILL IN FACT INTENSIFY ANOTHER 10 KNOTS IN THE NEXT FEW HOURS, BUT WILL THEN QUICKLY BEGIN TO FADE ONCE MORE. THE JTWC FORECAST POINTS CAPTURE A STEADY INTENSITY TREND THROUGH TAU 12, THEN SLOW WEAKENING UNTIL TAU 48, FOLLOWED BY RAPID WEAKENING. THIS FORECAST IS IN TIGHT AGREEMENT WITH THE MULTI-MODEL CONSENSUS, BUT CONFIDENCE IS MEDIUM IN THE EARLY STAGES, 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