20W(KRATHON) reached Super Typhoon Intensity now bearing down on TAIWAN//19W(JEBI)//TC 01S(ANCHA)//0209utc

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A RAGGED EYE FEATURED THAT IS CLOUD-FILLED AND COMPLETELY EXPOSES THE LOW-LEVEL CIRCULATION CENTER (LLCC). THE ERRATIC AND QUASI-STATIONARY MOTION HAS CONTINUED TO UPWELL COOLER WATER BELOW 26C. THE COOL WATER IS PRIMARILY DRIVING THE GRADUAL WEAKENING TREND WHILE THE ENVIRONMENT IS OTHERWISE FAVORABLE FOR INTENSIFICATION. UPPER-LEVEL OUTFLOW REMAINS EQUATORWARD BUT MODERATE INTO DIFFLUENT NORTHEASTERLY FLOW. AN EARLIER 020212Z METOP-C ASCAT IMAGE IN BETWEEN VALID TIMES SUPPORTS THE CURRENT TRACK POSITION AND ASSISTED IN IDENTIFYING THE WIND RADII. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED MSI AND SCATTEROMETRY. THE INITIAL INTENSITY OF 100 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE AGENCY AND OBJECTIVE FIXES LISTED BELOW.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TYPHOON (TY) 20W WILL REMAIN IN A COMPETING STEERING ENVIRONMENT FOR THE NEXT 24 HOURS AS IT REMAINS PINNED BETWEEN TWO SUBTROPICAL RIDGES TO THE EAST AND WEST. DURING THIS TIME, THE MOTION WILL CONTINUE TO BE ERRATIC BUT OVERALL NORTHEASTWARD. AFTER LANDFALL BETWEEN TAU 12-24, THE EASTERN RIDGE WILL PULL THE TYPHOON NORTHEASTWARD OVER THE MOUNTAINOUS TERRAIN OF TAIWAN. THE SYSTEM WILL CONTINUE TO GRADUALLY WEAKEN TO 90KTS BEFORE LANDFALL AS COOLER WATERS RISE TO THE SURFACE DUE TO THE SLOW STORM MOTION. AFTER THE SYSTEM MAKES LANDFALL, THE INTENSITY WILL DROP STARKLY DUE TO TOPOGRAPHIC INTERACTION WHILE TY 20W PASSES OVER TAIWAN. ULTIMATELY, THE SYSTEM WILL DISSIPATE OVER LAND BY TAU 72.

MODEL DISCUSSION: DETERMINISTIC MODEL AGREEMENT HAS IMPROVED OVER THE LAST SIX HOURS. GFS, WHICH IN PREVIOUS RUNS WAS AN OUTLIER WITH A WESTWARD TRACK, NOW ALIGNS WITH THE OVERALL NORTHEASTWARD TRACK WITH THE BULK OF THE JTWC MULTI-MODEL CONSENSUS MEMBERS. NEVERTHELESS, THERE IS STILL A LARGE SPREAD ACROSS MODEL SOLUTIONS AFTER LANDFALL DUE TO VARIABILITY IN THE TRACK AS THE SYSTEM INTERACTS WITH LAND. THE JTWC FORECAST LIES CLOSELY TO THE CONSENSUS MEAN FOR THE FIRST 48 HOURS AND EAST OF THE MEAN AT TAU 72. THE INTENSITY GUIDANCE IS IN TIGHT AGREEMENT AND HAS A CONSISTENT TREND OF GRADUAL WEAKENING ACROSS ALL CONSENSUS MEMBERS.

REMARKS: 020900Z POSITION NEAR 46.4N 154.7E. 02OCT24. TROPICAL STORM 19W (JEBI), LOCATED APPROXIMATELY 566 NM EAST-NORTHEAST OF MISAWA, JAPAN, HAS TRACKED NORTHEASTWARD AT 41 KNOTS OVER THE PAST SIX HOURS. TS JEBI IS CURRENTLY UNDERGOING EXTRATROPICAL TRANSITION THROUGH ITS NORTHEASTWARD TRACK INTO THE MID-LATITUDE BAROCLINIC ZONE AS SEA SURFACE TEMPERATURES HAVE DECREASED TO WELL BELOW 24 C AND VERTICAL WIND SHEAR (VWS) HAS INCREASED TO ABOVE 25 KNOTS. THE SYSTEM IS EXPECTED TO COMPLETE EXTRATROPICAL TRANSITION DURING THE NEXT SIX TO TWELVE HOURS AS AN EASTWARD PROGRESSING LONGWAVE TROUGH WILL PROVIDE TRANSITION SUPPORT INTO AN ASYMMETRIC COLD-CORE MID-LATITUDE LOW. ANIMATED VISIBLE IMAGERY AND A 89 GHZ 020300Z AMSR2 MICROWAVE IMAGE SUPPORT THE EXTRATROPICAL TRANSITION ASSESSMENT AS CONVECTION ASSOCIATED WITH 19W HAS BECOME POLEWARD AND EASTWARD OF THE LOW-LEVEL CIRUCATION CENTER, AND THE SYSTEMS VERTICAL STRUCTURE CONTINUES TO BECOME INCREASINGLY TILTED WITH HEIGHT. THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON WRNCEN PEARL HARBOR HI. THE SYSTEM WILL BE CLOSELY MONITORED FOR SIGNS OF REGENERATION. MINIMUM CENTRAL PRESSURE AT 020600Z IS 978 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 020600Z IS 24 FEET.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS DEEP CONVECTIVE BANDING FROM THE NORTHEAST WRAPPING INTO AN OBSCURED LOW-LEVEL CIRCULATION CENTER. A WEDGE OF SUBSIDENT DRY AIR IN THE NORTHWEST QUADRANT WRAPS INTO THE CIRCULATION CENTER. WATER VAPOR IMAGERY REVEALS STRONG RADIAL OUTFLOW ALOFT. A 020403Z METOP-C ASCAT IMAGE SUPPORTS THE CENTER POSITION AND THE 35KT WIND RADII. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED ANIMATED MSI AND SCATTEROMETRY. THE INITIAL INTENSITY OF 45 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED SCATTEROMETRY ACCOMPANIED BY THE AGENCY AND OBJECTIVE FIXES LISTED BELOW.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 01S IS FORECAST TO TRACK SOUTHWESTWARD APPROACHING THE AXIS OF A SUBTROPICAL RIDGE TO THE EAST. THE SYSTEM WILL TRACK INTO A REGION OF HIGH VERTICAL WIND SHEAR, WHICH WILL GRADUALLY ERODE THE SYSTEM INTENSITY TO 30KTS BY TAU 72. IN THE MEANTIME, DRY AIR WILL ALSO ENTRAIN INTO THE SYSTEM FROM THE WEST, WHICH WILL FURTHER DEGRADE THE ENVIRONMENT FOR INTENSIFICATION. THE UPPER-LEVEL ENVIRONMENT AFTER TAU 48 WILL BECOME STREAMLINED AND UNFAVORABLE. IT IS POSSIBLE THAT EARLIER WEAKENING MAY OCCUR DUE TO THE COMPOUNDING AFFECTS OF THE NEGATIVE ENVIRONMENTAL FEATURES.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN GOOD AGREEMENT REGARDING THE SOUTHWESTWARD TRACK DIRECTION AND TRACK SPEED, AS REPRESENTED BY A 200NM TRACK SPREAD BY TAU 72. THIS CONTRIBUTES TO THE HIGH CONFIDENCE IN THE JTWC TRACK FORECAST. THE INTENSITY FORECAST IS ALSO IN GOOD AGREEMENT, REFLECTING SLIGHT WEAKENING IN THE NEAR-TERM MOSTLY DUE TO INCREASING SHEAR AND DRY AIR BEFORE WEAKENING MORE RAPIDLY IN THE LATE-TERM. THE JTWC INTENSITY FORECAST REFLECTS THE MULTI-MODEL CONSENSUS MEAN.