TC 11S(FREDDY) Super Typhoon again rapidly approaching Mauritius & Réunion islands//Invest 99W//Invest 92S//Invest 93S//1903utc update

JTWC IS ISSUING 12HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON TC 11S(FREDDY).

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THAT TC 11S (FREDDY) HAS FULLY RECOVERED FROM THE DRY AIR INTRUSIONS IT FACED YESTERDAY AND HAS UNDERGONE A SHORT PERIOD OF EXTREMELY RAPID INTENSIFICATION, WITH DVORAK CURRENT INTENSITY (CI) ESTIMATES INCREASING FROM T5.5 TO T7.0 IN LESS THAN SIX HOURS. THIS OCCURRED AT OR NEAR THE DIURNAL CONVECTIVE MAXIMUM AND SAW CLOUD TOP TEMPERATURES DROP TO NEAR -80C WHILE EYE TEMPERATURES ROSE TO AN IMPRESSIVE +17C. THE PEAK OF THIS DRAMATIC INTENSIFICATION OCCURRED NEAR 182200Z AND IN THE SUBSEQUENT HOURS UP TO 190000Z, CLOUD TOP TEMPS HAVE WARMED TO -74C AND THE EYE INCREASED IN SIZE TO 25NM (NEARLY ONE-THIRD THE RADIUS OF THE INNER CORE OF THE SYSTEM) AND THUS INSTANTANEOUS DVORAK ESTIMATES HAVE STARTED TO FALL PRECIPITOUSLY (DOWN TO 6.1 BY 0000Z). A 182325Z SSMIS 91GHZ MICROWAVE IMAGE REVEALED WHAT LOOKS LIKE AN ANNULAR OR NEAR-ANNULAR CYCLONE, WITH A SOLID INNER CORE AND ONLY ONE VERY WEAK, DISTANT BANDING FEATURE. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE EYE FEATURES IN THE MICROWAVE AND EIR IMAGERY. THE INITIAL INTENSITY IS ASSESSED WITH HIGH CONFIDENCE AS WELL, THOUGH HEDGED SLIGHTLY LOWER THAN THE T7.0 CI'S FROM PGTW, FMEE AND FIMP DUE TO THE ALREADY RAPIDLY FALLING RAW ADT VALUES AND T6.5 CI'S FROM KNES AND DEMS. ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE, WITH LOW (0-5 KTS) VWS, WARM (28-29C) SSTS WITH MODEST OCEAN HEAT CONTENT (OHC) AND STRONG RADIAL OUTFLOW.

182325Z SSMIS 91GHZ MICROWAVE IMAGE REVEALED WHAT LOOKS LIKE AN ANNULAR OR NEAR-ANNULAR CYCLONE, WITH A SOLID INNER CORE AND ONLY ONE VERY WEAK, DISTANT BANDING FEATURE.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC FREDDY CONTINUES TO TRACK WEST-SOUTHWEST TOWARDS ITS RENDEZVOUS WITH MADAGASCAR. NO SIGNIFICANT CHANGE IN STEERING MECHANISM OR TRACK IS EXPECTED BEFORE LANDFALL ALONG THE EAST COAST OF MADAGASCAR. TRACK SPEEDS HAVE BEEN A CONSISTENT 11-12 KNOTS OVER THE PAST DAY, BUT SOME ACCELERATION IS EXPECTED AFTER TAU 24 AS THE RIDGE TO THE SOUTH BUILDS AND THE STEERING GRADIENT TIGHTENS UP A BIT. THE CURRENT FORECAST CALLS FOR THE SYSTEM TO TRACK SLIGHTLY FURTHER SOUTH THAN THE PREVIOUS FORECAST AND BRING IT INTO RELATIVELY CLOSE PROXIMITY OF BOTH MAURITIUS AND LA REUNION OVER THE NEXT 36 TO 48 HOURS, FOLLOWED BY LANDFALL AS A SIGNIFICANT TROPICAL CYCLONE ALONG THE EAST COAST OF MADAGASCAR AROUND TAU 60. AFTER CROSSING OVER THE ISLAND, THE SYSTEM WILL MOVE INTO THE MOZAMBIQUE CHANNEL. AS IT DOES SO, IT WILL COME UNDER THE STEERING INFLUENCE OF A DEVELOPING STR OVER SOUTH AFRICA AND GRADUALLY TURN ONTO A MORE WEST-NORTHWESTWARD TRACK TOWARDS MOZAMBIQUE. FROM AN INTENSITY PERSPECTIVE, SOME ADDITIONAL NEAR-TERM INTENSIFICATION IS POSSIBLE AS THERE IS NO INDICATION OF ANY EYEWALL REPLACEMENT CYCLES (EWRC) NOR ANY EXPECTED CHANGES IN THE ENVIRONMENT. THE ONLY FACTOR THAT COULD LIMIT A RUN AT 140 KNOTS WILL BE INNER-CORE DYNAMICAL FACTORS SUCH AS EYE ENLARGEMENT AND INNER-CORE INTRUSIONS FROM THE NEARBY POOL OF MID-LEVEL DRY AIR. AFTER TAU 24 HOWEVER, A STEADY BUT SLOW WEAKENING TREND IS EXPECTED AS THE SYSTEM MOVES OVER WATERS THAT WHILE STILL SUFFICIENTLY WARM, LACK SIGNIFICANT OHC. IT MUST BE MENTIONED HOWEVER THAT A POOL OF VERY WARM, HIGH OHC WATERS LIES DIRECTLY ALONG THE COAST OF MADAGASCAR AND COULD PROVIDE A SHORT-TERM BOOST IN INTENSITY JUST PRIOR TO LANDFALL, THOUGH THE SYSTEM WILL BE MOVING FAIRLY QUICKLY AND THIS WILL LIMIT THE POSSIBLE INTENSIFICATION. THE SYSTEM WILL RAPIDLY WEAKEN AS IT CROSSES MADAGASCAR AND IS EXPECTED TO BE A WEAK TROPICAL STORM AS IT MOVES OFF THE WEST COAST. ENVIRONMENTAL CONDITIONS ARE FORECAST TO BE VERY FAVORABLE IN THE MOZAMBIQUE CHANNEL AND WILL SUPPORT A FAIRLY QUICK REINTENSIFICATION OF THE SYSTEM AS IT MOVES TOWARDS EAST AFRICA.

MODEL DISCUSSION: DETERMINISTIC AND ENSEMBLE TRACK GUIDANCE IS IN VERY GOOD AGREEMENT, WITH ALL CONSENSUS MEMBERS CONTAINED WITHIN A VERY SMALL ENVELOPE THAT GRADUALLY EXPANDS TO JUST 85NM AT LANDFALL. THE GUIDANCE DIVERGES SOMEWHAT AFTER LANDFALL, BUT STILL REMAINS FAIRLY WELL BEHAVED WITH ONLY MARGINAL SPREAD THROUGH THE END OF THE FORECAST PERIOD. THE GFS, GFS ENSEMBLE AND HWRF TAKE A MORE NORTHWESTWARD TRACK THAN THE REMAINDER OF THE GUIDANCE PACKAGE AFTER TAU 96, WHICH REMAINS CONSISTENT WITH THE LAST FEW RUNS. THE JTWC FORECAST LIES NEAR THE CONSENSUS MEAN THROUGH TAU 72 AND HEDGES NORTH OF THE MEAN, TOWARDS THE GFS GROUPING AFTER TAU 96. INTENSITY GUIDANCE IS MIXED, WITH THE GFS CONTINUING TO BE UNREALISTICALLY LOW, FAR BELOW ALL THE OTHER GUIDANCE. HWRF IS ALSO ABOUT 20 KNOTS LOWER THAN THE DECAY-SHIPS AND COAMPS-TC (GFS) THROUGH LANDFALL. THE DECAY-SHIPS AND COAMPS-TC MEANWHILE INDICATE SLIGHT INTENSIFICATION THROUGH TAU 12 FOLLOWED BY GRADUAL WEAKENING THROUGH LANDFALL, AND ALL MODELS ARE POSITIVE ON THE RAPID WEAKENING AFTER LANDFALL. THE BULK OF THE GUIDANCE ALSO SHOWS REINTENSIFICATION AFTER TAU 96, WITH THE HWRF GOING AS HIGH AS 105 KNOTS BY TAU 132. THE JTWC FORECAST FOLLOWS THE COAMPS-TC LINE FOR THE FIRST 24 HOURS THEN REMAINS ROUGHLY CONSISTENT WITH THE CONSENSUS MEAN THROUGH THE REMAINDER OF THE FORECAST.

THE AREA OF CONVECTION (INVEST 99W) PREVIOUSLY LOCATED NEAR 7.2N 129.3E IS NOW LOCATED NEAR 11.9N 124.4E, APPROXIMATELY 255 NM SOUTHEAST OF MANILA, PHILIPPINES. ANIMATED MULTISPECTRAL IMAGERY (MSI) DEPICT A BROAD AREA OF DISORGANIZED CONVECTION OVER THE CENTRAL PHILIPPINE ISLANDS. A 190152Z ASCAT-B PASS SHOW A REGION OF GENERAL CYCLONIC TURNING DISRUPTED BY NUMEROUS ISLANDS. ENVIRONMENTAL ANALYSIS REVEALS THAT 99W IS IN A MARGINALLY FAVORABLE REGION FOR DEVELOPMENT DUE TO HIGH (25-30KT) VWS, OFFSET BY GOOD WESTWARD OUTFLOW AND WARM (26-27C) SSTS. THE PLACEMENT OF INVEST 99W IS DIFFICULT DUE TO THE LOW LEVEL CIRCULATION ESTIMATED TO BE OVER THE CENTRAL PHILIPPINE ISLANDS. LAND INTERACTION IS PLAYING A ROLE IN LIMITING CONSOLIDATION AT THIS TIME. DETERMINISTIC AND ENSEMBLE MODEL GUIDANCE INDICATE INVEST 99W WILL TRANSIT NORTH AND BECOME BETTER ORGANIZED IN APPROXIMATELY 18-24 HOURS OVER THE WATERS NORTHEAST OF LAMON BAY. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1007 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS MEDIUM.

DETERMINISTIC AND ENSEMBLE MODEL GUIDANCE INDICATE INVEST 99W WILL TRANSIT NORTH AND BECOME BETTER ORGANIZED IN APPROXIMATELY 18-24 HOURS OVER THE WATERS NORTHEAST OF LAMON BAY.