TC 08S(BATSIRAI): CAT 3 US bearing down on Eastern Madagascar// TC 10S(CLIFF) near peak intensity//Invest 92P on the map,05/03utc

JTWC IS ISSUING 12HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON TC 08S(BATSIRAI) AND TC 10S(CLIFF).

05/02UTC.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TROPICAL CYCLONE 08S (BATSIRAI) IS EXPECTED TO MAKE LANDFALL IN SOUTHERN MADAGASCAR BETWEEN 12 AND 24 HOURS. WHILE THE ENVIRONMENT IS GENERALLY FAVORABLE, THE IMPERFECT STRUCTURE OF THE INNER CORE AND THE LIKELY ENTRAINMENT OF DRY AIR IN THE NORTHERN SEMICIRCLE SHOULD PREVENT ANY INTENSIFICATION PRIOR TO LANDFALL, AND IN FACT SLIGHT WEAKENING IS POSSIBLE GIVEN CURRENT SATELLITE TRENDS. BATSIRAI IS BEING STEERED WEST-SOUTHWESTWARD BY THE SUBTROPICAL RIDGE TO THE SOUTH, AND THIS TRACK WILL TAKE THE STORM ACROSS MADAGASCAR AND INTO THE MOZAMBIQUE CHANNEL BY 48 HOURS. THE INTENSITY WILL BE GREATLY REDUCED BY THIS TIME DUE TO THE CROSSING OF MOUNTAINOUS TERRAIN, AROUND 40 KT. AROUND THE TIME OF REEMERGENCE OVER WATER, THE SUBTROPICAL RIDGE IS EXPECTED TO WEAKEN AS AN UPPER-LEVEL TROUGH SKIRTS BY TO THE SOUTH, RESULTING IN BATSIRAI TURNING SOUTHWARD. THE CYCLONE WILL HAVE 24-48 HOURS OF TIME OVER WARM WATER BEFORE SEA SURFACE TEMPERATURES RAPIDLY DROP TO BELOW 26 DEGREES CELSIUS BY AROUND 96 HOURS. DURING THIS PERIOD, SOME REINTENSIFICATION IS LIKELY. HOWEVER, THE REINTENSIFICATION IS LIKELY TO BE MUTED DUE TO A COUPLE OF FACTORS. FIRSTLY, THE UPPER-LEVEL ANTICYCLONE IS FORECAST TO REMAIN ANCHORED EAST OF MADAGASCAR, IMPARTING MODERATE NORTHERLY SHEAR OF 15-20 KT ON THE CYCLONE. THIS IS EXPECTED TO PUSH A PREEXISTING MID-LEVEL DRY AIR MASS IN THE MOZAMBIQUE CHANNEL INTO THE NORTHERN SEMICIRCLE OF BATSIRAI, LEADING TO EROSION OF PART OF THE INNER CORE. SECONDLY, MODELS CURRENTLY AGREE THAT THE VORTEX STRUCTURE FOLLOWING THE CROSSING OF MADAGASCAR WILL BE RATHER BROAD, WHICH WOULD NOT FACILITATE RAPID INTENSIFICATION. THE JTWC FORECAST CALLS FOR A SECONDARY PEAK OF 50 KT IN 72-96 HOURS, WHICH IS SLIGHTLY ABOVE THE MULTI-MODEL CONSENSUS. AFTER 96 HOURS, AS THE CYCLONE MOVES OVER COLDER WATERS, CONVECTION IS LIKELY TO DWINDLE, LEADING TO THE ONSET OF SUBTROPICAL TRANSITION BY 120 HOURS.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THAT THE COLD RING AROUND THE EYE HAS WARMED SOMEWHAT OVER THE PAST 12 HOURS. A 042211Z AMSR2 MICROWAVE PASS REVEALED THAT THE NORTHERN EYEWALL HAS ERODED, AND PERIODIC DISRUPTIONS TO THE EYEWALL ARE EVIDENT IN ANIMATED EIR IMAGERY. GIVEN THE LACK OF VERTICAL SHEAR OR COLD WATER, IT SEEMS MOST LIKELY THAT THIS EROSION IS DUE TO A COMBINATION OF DOWNSLOPING FLOW ON THE EASTERN SIDE OF MADAGASCAR, ALONG WITH MID-LEVEL DRY AIR BEING ADVECTED OVER THE ISLAND AND INTO THE NORTHERN SEMICIRCLE OF THE STORM. THIS DIAGNOSIS IS SUPPORTED BY THREE-DIMENSIONAL MODEL ANALYSES. A SENTINNEL-1A SAR PASS AT 041502Z FOUND THAT THE INTENSITY WAS 105 KT/CAT 3 US AT THE TIME, SLIGHTLY BELOW THE MEAN OF SUBJECTIVE DVORAK ESTIMATES. GIVEN THE SLIGHT DEGRADATION OF THE SATELLITE PRESENTATION AND ASSOCIATED DVORAK ESTIMATES SINCE THAT TIME, THE INITIAL INTENSITY IS LOWERED TO 100 KT/CAT 3 US.

THE NORTHERN EYEWALL HAS ERODED, AND PERIODIC DISRUPTIONS TO THE EYEWALL ARE EVIDENT IN ANIMATED EIR IMAGERY

MODEL DISCUSSION: THE TRACK GUIDANCE IS IN TIGHT AGREEMENT THROUGH 72 HOURS, BUT SPREAD IN FORWARD SPEED INCREASES SIGNIFICANTLY THEREAFTER. THE MULTI-MODEL CONSENSUS DURING THE 72-120 HOUR PERIOD HAS ACCELERATED SINCE 12 HOURS AGO, AND THE JTWC FORECAST FOLLOWS SUIT. THE JTWC INTENSITY FORECAST IS ALSO HIGH CONFIDENCE THROUGH 72 HOURS, CLOSE TO THE MULTI-MODEL CONSENSUS, AND THEN LIES SLIGHTLY ABOVE CONSENSUS THROUGH 120 HOURS.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THE SYSTEM IS NOW FORECAST TO DISSIPATE BY TAU 72. FORECAST DISCUSSION: TROPICAL CYCLONE 10S (CLIFF) HAS LIKELY PEAKED IN INTENSITY, OR WILL DO SO WITHIN THE NEXT 12 HOURS. THE MID-LEVEL DRY AIR MASS NOW WRAPPING INTO THE NORTHERN SEMICIRCLE IS LIKELY TO BEGIN DISRUPTING THE INNER CORE AS NORTHERLY SHEAR PUSHES IT INWARD TOWARD THE LOW-LEVEL CENTER (LLC). THE STORM IS ALSO EXPECTED TO TRACK OVER SLIGHTLY COOLER SEA SURFACE TEMPERATURES OF 27 DEGREES CELSIUS (COMPARED TO CURRENT VALUES OF 28), WHICH WILL PROVIDE LESSENING SUPPORT FOR DEEP CONVECTION. NUMERICAL MODELS ARE IN UNANIMOUS AGREEMENT THAT THE LLC WILL BECOME FULLY EMBEDDED WITHIN THE DRY AIR MASS DURING THE 12-24 HOUR PERIOD, RESULTING IN STEADY WEAKENING. ALOFT, AN UPPER-LEVEL TROUGH TO THE SOUTHWEST IS BEGINNING TO SPLIT, A PROCESS WHICH WILL COMPLETE IN AROUND 24 HOURS. IN ITS WAKE, AN UPPER-LEVEL ANTICYCLONE WILL BECOME ESTABLISHED TO THE EAST OF CLIFF, RESULTING IN A CONTINUATION OF NORTHERLY VERTICAL SHEAR. THIS IS EXPECTED TO PREVENT ANY REINTENSIFICATION AS THE SYSTEM REMAINS EMBEDDED IN A DRY AIR MASS FOR THE FORESEEABLE FUTURE. CLIFF'S INTENSITY IS FORECAST TO FALL BELOW WARNING THRESHOLD IN 48 HOURS, AND THE JTWC FORECAST TERMINATES AT 72 HOURS. THE TRACK FORECAST IS STRAIGHT FORWARD, WITH CLIFF BEING STEERED PRIMARILY BY A MID-LEVEL RIDGE TO THE SOUTH DURING THE FORECAST PERIOD, COMBINED WITH INFLUENCE FROM A BROAD MID-LEVEL CYCLONIC CIRCULATION TO THE NORTHWEST. THIS IS EXPECTED TO RESULT IN A GENERALLY WEST-SOUTHWESTWARD MOTION THROUGH 72 HOURS.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS DEEP CONVECTION WRAPPING AROUND THE SOUTHERN AND WESTERN SEMICIRCLE WITH TIGHT CURVATURE AROUND THE MID-LEVEL CENTER, THOUGH RAGGED IN APPEARANCE. THE LOW-LEVEL CIRCULATION (LLC) APPEARS TO BE CENTERED NORTH OF THE MID-LEVEL CENTER BENEATH THE EDGE OF THE CONVECTIVE CANOPY, BASED ON A 041627Z ASCAT-C PASS. THE LLC IS ELONGATED NORTH-NORTHEAST TO SOUTH-SOUTHWEST, WITH A BROAD BAND OF 35-45 KT WINDS WRAPPING INTO THE WESTERN SIDE FROM THE SOUTH. THE WIND FIELD STRUCTURE IS CONSISTENT WITH A MODERATELY SHEARED VORTEX, TILTED SOUTHWARD WITH HEIGHT. THIS IS SUPPORTED BY THE PRESENCE OF CIRRUS DEBRIS MOVING QUICKLY INWARD TOWARD THE LLC FROM THE NORTH IN ANIMATED SATELLITE IMAGERY. THE HIMAWARI-8 7.3 MICROMETER BAND REVEALS A DRY AIR MASS ADJACENT TO THE CIRCULATION ON THE WEST SIDE, BEGINNING TO WRAP INTO THE NORTHERN SEMICIRCLE. THE INITIAL INTENSITY IS SET AT 45 KT BASED ON 40-45 KT WINDS IN THE SOUTHWEST QUADRANT IN THE AFOREMENTIONED ASCAT-C PASS, CONSISTENT WITH THE SUBJECTIVE DVORAK ESTIMATE OF T3.0 (45 KT) FROM PGTW.

MODEL DISCUSSION: TRACK GUIDANCE HAS MODERATE SPREAD THROUGH 72 HOURS. THE JTWC FORECAST IS ON THE NORTHERN SIDE OF THE ENVELOPE, STICKING CLOSE TO THE MEAN OF GFS, GEFS ENSEMBLE MEAN, AND ECMWF. THE INTENSITY GUIDANCE IS UNANIMOUS IN SHOWING WEAKENING DURING THE NEXT 72 HOURS, AND THE JTWC FORECAST IS JUST BELOW THE MULTI-MODEL CONSENSUS.

THE AREA OF CONVECTION (INVEST 92P) PREVIOUSLY LOCATED NEAR 17.7S 152.1E IS NOW LOCATED NEAR 17.7S 153.2E, APPROXIMATELY 380 KM EAST-SOUTHEAST OF WILLIS ISLAND, AUSTRALIA. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS AN ELONGATED, DISORGANIZED DISTURBANCE EMBEDDED WITHIN A WEST-NORTHWEST TO EAST-SOUTHEAST ORIENTED FRONTAL SYSTEM. A 050347Z AMSR2 36GHZ COLOR COMPOSITE MICROWAVE IMAGE REVEALS NO DISCRETE LOW-LEVEL CIRCULATION WITH HIGHLY DISORGANIZED SHALLOW BANDS OF CONVECTION ACROSS THE CORAL SEA. THE DISTURBANCE IS LOCATED WITHIN A BROAD UPPER-LEVEL TROUGH UNDER MODERATE WESTERLIES WITH BROAD DIFFLUENCE TO THE NORTH ASSOCIATED WITH AN UPPER-LEVEL RIDGE. VERTICAL WIND SHEAR REMAINS LOW TO MODERATE WITH WARM SEA SURFACE TEMPERATURES OF 29-30 DEGREES CELSIUS. THE DISTURBANCE IS EXPECTED TO TRACK EAST-SOUTHEASTWARD TOWARD VANUATU ALONG THIS FRONTAL BOUNDARY FOR THE NEXT TWO DAYS WITHIN A MARGINALLY FAVORABLE ENVIRONMENT. AFTER TWO DAYS, NUMERICAL MODELS GENERALLY AGREE THAT SOME DEVELOPMENT WILL OCCUR AS THE DISTURBANCE TRACKS UNDER A MORE FAVORABLE UPPER-LEVEL ENVIRONMENT. THIS ZONE WILL BE MONITORED CLOSELY, AS A COMPLEX ENVIRONMENT COULD LEAD TO MULTIPLE CIRCULATIONS FORMING IN CLOSE PROXIMITY WITHIN THE SOUTH PACIFIC CONVERGENCE ZONE IN THE GENERAL VICINITY OF NEW CALEDONIA, VANUATU, FIJI, AND TONGA DURING THE NEXT SEVERAL DAYS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 999 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS LOW.