WDPN31 PGTW 070900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 24W (YINXING) WARNING NR 017// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 18.5N 122.4E INITIAL INTENSITY: 125 KTS GEOGRAPHIC REFERENCE: 247 NM NORTH-NORTHEAST OF MANILA, PHILIPPINES MOVEMENT PAST 6 HOURS: WESTWARD AT 07 KTS SIGNIFICANT WAVE HEIGHT: 41 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: TYPHOON (TY) 24W (YINXING) IS CURRENTLY MAKING LANDFALL ON THE EXTREME NORTHEAST TIP OF LUZON, NEAR POZO ROBO BEACH AT THE 0600Z HOUR. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A 20NM WIDE EYE, WITH EMBEDDED MESOVORTICES RAPIDLY SPINNING AROUND THE CENTER, ON THE INNER EDGE OF THE STRONG EYEWALL. AT 0000Z, THE EYE WAS CLOUD-FILLED, WITH EYE TEMPERATURES NEARING ZERO CELSIUS. RAPID WARMING DUE TO STRONG SUBSIDENCE IN THE EYE RESULTED IN A CLEARING OF THE EYE AND EYE TEMPS INCREASING TO NEAR 19C BY ANALYSIS TIME. DVORAK INTENSITY ESTIMATES CORRESPONDINGLY INCREASED, WITH MULTIPLE AGENCIES INCREASING TO T7.0. A 070440Z NOAA-20 ATMS 88.2GHZ MICROWAVE IMAGE SHOWED A WELL-DEFINED EYEWALL, CLOSED IN ALL BUT THE WESTERN SIDE, WHERE IT WAS ALREADY BEGINNING TO INTERACT WITH TERRAIN. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE 20NM EYE IN THE MSI. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE, CONSISTENT WITH A MEAN OF THE SUBJECTIVE AND OBJECTIVE INTENSITY ESTIMATES NOTED BELOW. THE ENVIRONMENT REMAINS FAVORABLE, WITH THE EXCEPTION OF LAND INTERACTION, THE EFFECTS OF WHICH WILL OVERWHELM THE OTHERWISE POSITIVE ENVIRONMENTAL FACTORS IN THE NEAR-TERM. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) TO THE NORTH, EXTENDING FROM SOUTH OF HONG KONG, OVER TAIWAN AND INTO THE WESTERN PACIFIC NORTH OF THE NORTHERN MARIANAS. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T7.0 - 140 KTS RJTD: T6.5 - 127 KTS KNES: T7.0 - 140 KTS DEMS: T6.5 - 127 KTS CIMSS SATCON: 119 KTS AT 070148Z CIMSS ADT: 127 KTS AT 070530Z CIMSS D-PRINT: 106 KTS AT 070630Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 5-10 KTS SST: 28-29 CELSIUS OUTFLOW: STRONG RADIAL OTHER FACTORS: POLEWARD OUTFLOW CHANNEL. 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 24W WILL TRACK WESTWARD ALONG THE NORTHERN COAST OF LUZON FOR THE NEXT 12 HOURS. TRACK SPEEDS WILL SLOW DOWN, AS ALREADY SEEN IN THE ANIMATED MSI, AS THE LOCALIZED EFFECTS OF TERRAIN-INDUCED DRAG SLOW THE SYSTEM DOWN A BIT. BY TAU 12, THE SYSTEM WILL BE REACHING THE NORTHWEST TIP OF LUZON AND MOVING BACK INTO THE OPEN WATERS OF THE SOUTH CHINA SEA (SCS). TRACK SPEEDS WILL INCREASE TO ABOUT 10 KNOTS AFTER THE SYSTEM MOVES AWAY FROM LAND, AND THE STEERING GRADIENT ALONG THE SOUTHERN SIDE OF THE STR TIGHTENS UP. BY TAU 48, A PASSING MID-LATITUDE TROF WILL PUSH IN FROM THE WEST AND GENERATE A BREAK IN THE STEERING RIDGE NEAR HONG KONG. THE BREAK IN THE RIDGE IS NOT EXPECTED TO BE STRONG ENOUGH TO PULL TY 24W UP TO THE NORTH MUCH, BUT IT WILL LEAD TO A WEAKENED STEERING GRADIENT, AND TY 24W WILL START TO SLOW DOWN ONCE MORE BY TAU 48, REACHING ITS SLOWEST SPEED OF ADVANCE BY TAU 72. TY 24W LIKELY REACHED PEAK INTENSITY AS IT WAS MAKING LANDFALL BUT WILL WEAKEN STEADILY AND RAPIDLY OVER THE NEXT 12 HOURS AS IT MOVES WESTWARD AND STRADDLES THE NORTH COAST OF LUZON. THE FORECAST CALLS FOR ABOUT 25 KNOTS OF WEAKENING, WITH THE SYSTEM MOVING INTO THE SCS AS A 100 KNOT TYPHOON. SOME REINTENSIFICATION IS EXPECTED AFTER TAU 24, BUT RELATIVELY COOL (27-28C) WATERS AND LIMITED OUTFLOW ALOFT WILL KEEP A LID ON THE PACE OF INTENSIFICATION. BY TAU 48, SOUTHERLY SHEAR WILL BEGIN TO PICK UP, USHERING IN A WEDGE OF DRY MID-LEVEL AIR. BY TAU 72, SOUTHERLY SHEAR, ESPECIALLY IN THE MID-LEVELS, ALONG WITH AN INFLUX OF VERY DRY AIR, IS EXPECTED TO DECAPITATE THE VORTEX, MARKING THE ONSET OF RAPID WEAKENING. AS THE VORTEX SHALLOWS, THE TRACK SHIFTS SHARPLY SOUTHWESTWARD AFTER TAU 72, TRACKING THE LOW TO MID-LEVEL FLOW PATTERN. THE SYSTEM WILL CONTINUE TO WEAKEN, NEARING FULL DISSIPATION, THROUGH TAU 120, AS IT CONTINUES TO TRACK TOWARDS THE COAST OF CENTRAL VIETNAM. MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU 72, WITH MINIMAL CROSS-TRACK SPREAD, AND MARGINAL ALONG-TRACK SPREAD, AFTER TAU 48. THE GFS IS THE NORTHERNMOST OUTLIER, TAKING THE SYSTEM ON A VERY SLOW TRACK TO THE NORTH, UP TO ABOUT 20N BY TAU 72, WHILE THE REMAINDER OF THE CONSENSUS IS TIGHTLY CLUSTERED AROUND THE JTWC FORECAST, THOUGH THE UKMET, GALWEM AND UKMET ENSEMBLE DO PUSH THE SYSTEM FURTHER WEST DURING THIS TIMEFRAME THAN THE REMAINDER OF THE CONSENSUS MEMBERS. AFTER TAU 72, CROSS-TRACK UNCERTAINTY INCREASES, WITH A SPREAD OF 255NM BETWEEN THE UKMET AND ITS ENSEMBLE MEAN, THOUGH ALL CONSENSUS MEMBERS AGREE ON THE SHARP TURN SOUTHWARD AFTER TAU 72. THE JTWC FORECAST LIES ON THE NORTHERN SIDE OF THE GUIDANCE PACKAGE TO TAU 72 THEN CLOSE TO THE CONSENSUS MEAN THEREAFTER. INTENSITY GUIDANCE IS MIXED IN TERMS OF HOW MUCH WEAKENING WILL OCCUR OVER THE NEAR-TERM, AND THUS THE SECOND PEAK IN THE SCS. THE HAFS-A IS ON THE HIGH END, WITH ONLY 10KTS OF WEAKENING AND A PEAK NEAR 120 KNOTS AT TAU 48. THE GFS ON THE OTHER HAND WEAKENS THE SYSTEM TO JUST 70 KNOTS AND SHOWS NO REINTENSIFICATION, AND THE HWRF IS NEAR THE MIDDLE BETWEEN THOSE TWO OUTLIERS. THE JTWC FORECAST IS SLIGHTLY LOWER THAN THE HWRF TO TAU 24, BUT THEN FOLLOWS IT THROUGH THE REMAINDER OF THE FORECAST. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN