TD 24W(KOMPASU) Final Warning/ TS 23W(NAMTHEUN) taking on Subtropical features/TD 16E(PAMELA) Final Warning,14/09utc

JTWC IS ISSUING 6HOURLY WARNINGS ON TD 23W. FINAL WARNING ON TD 24W WAS ISSUED AT 14/09UTC. 3 HOURLY SATELLITE BULLETINS ARE ISSUED ON BOTH SYSTEMS.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TD NAMTHEUN WILL CONTINUE ON ITS CURRENT TRACK FOR THE DURATION OF THE FORECAST UNDER THE STEERING INFLUENCE OF THE SUBTROPICAL RIDGE(STR). THE MARGINAL ENVIRONMENT WILL SUSTAIN THE CURRENT INTENSITY FOR UP TO 24H. AFTERWARD, INCREASING VERTICAL WIND SHEAT AND COOLING SSTS WILL GRADUALLY ERODE THE SYSTEM TOWARD DISSIPATION BY 48H, POSSIBLY SOONER. CONCURRENTLY, THE CYCLONE WILL CONTINUE TO GAIN MORE SUBTROPICAL CHARACTERISTICS.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A MEDIUM-SIZED SYSTEM WITH PERSISTENT CONVECTION OVER THE CENTRAL DENSE OVERCAST (CDO) THAT IS TRAILING A FEEDER BAND SOUTHWARD. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON LOW CLOUD LINE TRACING INTO THE OBSCURED LOW LEVEL CIRCULATION (LLC) AND EXTRAPOLATION FROM A WEAK LLC FEATURE IN THE 140232Z AMSR MICROWAVE IMAGE THE INITIAL INTENSITY OF 30KNOTS IS ASSIGNED WITH MEDIUM CONFIDENCE BASED ON AN OVERALL ASSESSMENT OF AGENCY AND AUTOMATED DVORAK ESTIMATES AND REFLECTS THE 6-HR PERSISTENT CONVECTIVE SIGNATURE OF THE SYSTEM. ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH STRONG EQUATORWARD OUTFLOW AND WARM SST OFFSET BY STRONG VWS. THE SYSTEM HAS BEGUN TO EXHIBIT SUBTROPICAL CHARACTERISTICS, I.E., ASYMMETRIC WIND FIELD AND VORTICITY SIGNATURE AND THE CDO OFFSET EASTWARD AND POLEWARD OF THE LLC. THE CYCLONE IS TRACKING ON THE POLEWARD SIDE OF THE STR TO THE SOUTH.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY TIGHT AGREEMENT, GRADUALLY SPREADING TO 180KM AT 48H, LENDING HIGH CONFIDENCE TO THE JTWC TRACK FORECAST. HOWEVER, THERE IS ONLY MEDIUM CONFIDENCE THE INTENSITY FORECAST GIVEN THE UNCERTAINTY IN THE SUBTROPICAL TRANSITION.

140900Z POSITION NEAR 19.5N 106.4E. 14OCT21. TROPICAL DEPRESSION 24W (KOMPASU), LOCATED APPROXIMATELY 101 NM SOUTH-SOUTHEAST OF HANOI, VIETNAM, HAS TRACKED WEST- NORTHWESTWARD AT 15 KM/H OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS THE SYSTEM IS COMPLETELY STRIPPED OF ANY DEEP CONVECTION, FULLY EXPOSING A RAGGED AND WEAK LOW LEVEL CIRCULATION WHERE THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE. THE INITIAL INTENSITY IS BASED ON OVERALL ASSESSMENT OF AGENCY DVORAK ESTIMATES AND EXTRAPOLATED FROM NEARBY SURFACE OBSERVATIONS. ENVIRONMENTAL ANALYSIS INDICATES MEDIUM (15-20KT) VERTICAL WIND SHEAR, GREATLY DIMINISHED OUTFLOW, AND DRY AIR ENTRAINMENT FROM THE NORTHWEST HAVE DRASTICALLY ERODED THE ASSOCIATED CONVECTION. THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON WRNCEN PEARL HARBOR HI.