TC 05S(DARIAN) reached Super Typhoon intensity once again//TC 06S(ELLIE) rapidly made landfall//Invest 98B// 2406utc

JTWC IS ISSUING 12HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON TC 05S(DARIAN). 3HOURLY SATELLITE BULLETINS ARE ISSUED ON INVEST 98B.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A RAGGED EYE FEATURE, WHICH HAS SIGNIFICANTLY ERODED SINCE THE IMPRESSIVE PEAK 12 HOURS AGO. THE CLOUD TOPS SURROUNDING THE EYE HAVE WARMED TO -70 TO -78 CELSIUS, WHILE THE EYE TEMPERATURE HAS NOW TURNED NEGATIVE AGAIN. A SERIES OF 91GHZ MICROWAVE IMAGERY SHOWED SIGNS OF AN EYEWALL REPLACEMENT CYCLE (EWRC) BEGINNING AROUND THE 231800Z HOUR, WITH THE GMI 89GHZ IMAGE AT THAT TIME SHOWING THE FIRST SIGNS OF A SECONDARY EYEWALL, WHICH WAS MORE PRONOUNCED BY THE 232215Z IMAGE AND BY THE 240015 SSMIS PASS, THE SECONDARY EYEWALL APPEARS TO HAVE MERGED WITH THE INNER ONE. THE CIMSS M-PERC FORECAST INDICATED A HIGH LIKELIHOOD OF AN EWRC AFTER THE 231200Z HOUR, WHICH APPEARS TO HAVE BORN OUT. COMBINED WITH THE NOW QUASI-STATIONARY MOTION RESULTING IN SIGNIFICANT UPWELLING OF COOLER WATERS, THE SYSTEM HAS BEGUN TO RAPIDLY WEAKEN. THE INITIAL INTENSITY IS LOWERED TO 115 KNOTS WITH MEDIUM CONFIDENCE, GENERALLY NEAR THE AVERAGE BETWEEN THE AGENCY DATA-T NUMBERS AND CURRENT INTENSITY ESTIMATES, SUPPORTED BY 110-115 KNOT ESTIMATES FROM ADT, OPEN-AIIR AND A 232016Z AMSR2 WINDSPEED ESTIMATE OF 111 KNOTS. THE SYSTEM IS NOW IN A WEAK STEERING ENVIRONMENT LEADING TO QUASI-STATIONARY MOTION OF THE PAST SIX HOURS. CONDITIONS ARE GENERALLY FAVORABLE WITH THE EXCEPTION OF THE LOCALIZED COOL SSTS.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TROPICAL CYCLONE 05S (DORIAN) HAS MOVED INTO A COMPETING AND WEAK STEERING PATTERN, AS THE STR TO THE SOUTH WEAKENS AND RETROGRADES TO THE WEST, ALLOWING FOR THE STRENGTHENING NER TO THE NORTHEAST TO TAKE OVER AS THE DOMINANT STEERING MECHANISM. THIS STEERING SHIFT WILL BE COMPLETE WITHIN THE NEXT 12 HOURS AND TC 05S WILL THEN BEGIN TO ACCELERATE TO THE SOUTHEAST. BETWEEN TAUS 36 AND 60, THE NER WILL QUICKLY SLIDE TO THE WEST, TO A POSITION SOUTH OF INDIA AND WEAKEN, WHILE THE STR TO THE SOUTHWEST WILL MOVE EASTWARD AND STRENGTHEN. THIS WILL RESULT IN ANOTHER PERIOD OF WEAK STEERING DURING THIS TIMEFRAME AS THE TWO STEERING RIDGES COMPETE FOR DOMINANCE. BY TAU 72, THE STEERING INFLUENCE WILL SHIFT OVER TO THE STR TO THE SOUTH, PUSHING TC 05S ONTO A SOUTH-SOUTHWESTWARD TRACK THROUGH THE REMAINDER OF THE FORECAST PERIOD. OVER THE PREVIOUS 12 HOURS TC 05S RAPIDLY INTENSIFIED, BRIEFLY REACHING 130 KNOTS, BEFORE A COMBINATION OF AN EWRC AND OCEANIC UPWELLING LED TO RAPID DECREASE IN INTENSITY. NOW THAT THE SYSTEM HAS SLOWED TO A CRAWL OVER THE AREA OF MOST INTENSE UPWELLING, THE SYSTEM WILL CONTINUE TO WEAKEN STEADILY THROUGH THE NEXT 36 HOURS. AROUND TAU 36, THE SYSTEM WILL BACK MOVE OVER A WARM TONGUE OF HIGHER OCEAN HEAT CONTENT, BUT AT THE SAME TIME WILL EXPERIENCE SOME INCREASED SHEAR AND CONVERGENCE ALOFT DUE TO THE DEVELOPMENT OF AN UPPER-LEVEL LOW TO THE WEST, RESULTING IN A PERIOD OF STEADY INTENSITY THROUGH TAU 72. AFTER TAU 72, THE SYSTEM WILL MORE RAPIDLY WEAKEN AS IT MOVES SOUTHWESTWARD OVER STEADILY COOLER WATERS LESS THAN 26C, FORECAST TO WEAKEN TO JUST 45 KNOTS BY THE END OF THE FORECAST PERIOD.

MODEL DISCUSSION: DETERMINISTIC AND ENSEMBLE TRACK GUIDANCE IS IN GOOD AGREEMENT ON THE OVERALL TRACK, WITH THE JTWC TRACK FORECAST LYING CLOSE TO THE MULTI-MODEL CONSENSUS MEAN, AND ROUGHLY IN THE MIDDLE OF THE GUIDANCE ENVELOPE, WHICH GRADUALLY EXPANDS FROM 90NM AT TAU 72 TO 180NM AT TAU 120. INTENSITY GUIDANCE IS IN GOOD AGREEMENT THROUGH THE FIRST 36 HOURS, BUT THEN DIVERGES RATHER SIGNIFICANTLY. WITH THE BULK OF THE MODELS, WITH THE EXCEPTION OF HWRF, SHOWING A VERY RAPID WEAKENING THROUGH THE FORECAST PERIOD. THE GFS DECAY-SHIPS EVEN DISSIPATES THE SYSTEM BY TAU 72. THE COUPLED HWRF MODEL HOWEVER CAPTURES THE MOVEMENT BACK OVER THE WARM TONGUE THAT THE OTHER MODELS ARE NOT PICKING UP ON, AND SHOWS A FLATTENING OF THE INTENSITY CURVE BETWEEN TAU 36 AND TAU 72. THE JTWC FORECAST CLOSELY TRACKS THE HWRF, PARTICULARLY AFTER TAU 36.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THAT TROPICAL CYCLONE 05S (DARIAN) HAS CONTINUED TO INTENSIFY AT A RAPID PACE DURING THE PAST SIX HOURS. DESPITE INDICATIONS OF AN OPEN EYEWALL TO THE SOUTHWEST IN A 231133Z SSMIS MICROWAVE IMAGE AND EIR IMAGERY, THE EYE HAS WARMED TO AROUND +10 DEGREES CELSIUS, AND AGENCY DVORAK ESTIMATES HAVE RISEN DRAMATICALLY TO T6.5 OR T7.0, WITH RAW ADT VALUES AS HIGH AS T6.9. THE INITIAL INTENSITY IS THUS REVISED UPWARD TO 135 KT. THE ENVIRONMENT REMAINS OVERALL FAVORABLE WITH LOW VERTICAL SHEAR, AND THE CYCLONE APPEARS TO BE MOVING OVER A PATCH OF WARMER SEA SURFACE TEMPERATURES DURING THE LAST 12 HOURS.

THE AREA OF CONVECTION (INVEST 98B) PREVIOUSLY LOCATED NEAR 9.2N 84.9E IS NOW LOCATED NEAR 10.8N 85.4E, APPROXIMATELY 329 NM EAST- SOUTHEAST OF CHENNAI, INDIA. ANIMATED EIR AND A 231139Z SSMIS 91GHZ MICROWAVE IMAGE DEPICT FLARING CONVECTION BEING SHEARED TO THE NORTHEAST OF A PARTIALLY EXPOSED LLC. ANALYSIS INDICATES 98B IS IN A MARGINALLY FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH MODERATE TO HIGH (20-25 KNOT) VWS OFFSET BY DECENT POLEWARD OUTFLOW ALOFT AND WARM (27-28C) SEA SURFACE TEMPERATURES. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 98B WILL CONTINUE TO TRACK GENERALLY SOUTHWESTWARD TOWARDS SRI LANKA OVER THE NEXT 24-48 HOURS AND GRADUALLY WEAKEN DUE TO INCREASING VWS AND COOLING SST. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 23 TO 28 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1003 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS LOW.

GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 98B WILL CONTINUE TO TRACK GENERALLY SOUTHWESTWARD TOWARDS SRI LANKA OVER THE NEXT 24-48 HOURS AND GRADUALLY WEAKEN DUE TO INCREASING VWS AND COOLING SST.