TC 08S(BATSIRAI): powerful CAT 4, eye-wall replacement cycle possible within 24hours//TC 09P: struggling due to mid-level dry air,02/03utc

JTWC IS ISSUING 12HOURLY WARNINGS ON TC 08S(BATSIRAI) AND 6HOURLY WARNINGS ON TC 09P. 3HOURLY SATELLITE BULLETINS ARE ISSUED FOR BOTH SYSTEMS.

02/0145UTC.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC 08S IS FORECAST TO CONTINUE TRACKING WEST-SOUTHWESTWARD OVER THE NEXT 24 TO 36 HOURS ALONG AN EXTENSION OF THE SUBTROPICAL RIDGE (STR) CENTERED TO THE SOUTHWEST. BY 36H THE STR WILL QUICKLY MOVE TO THE EAST AND SLIDE INTO A POSITION DUE SOUTH OF THE SYSTEM AND TC 08S WILL SLOW DOWN AND SHIFT TO A WESTWARD TRACK DURING THIS TIME. AFTER 48H AND DEEP, MID-LATITUDE TROUGH WILL ERODE THE STEERING RIDGE FROM THE WEST, AND TC 08S WILL TURN ONTO A MORE SOUTHWESTWARD TRACK ONCE MORE AS IT APPROACHES THE CENTRAL COAST OF MADAGASCAR. THE SYSTEM IS EXPECTED TO MAKE LANDFALL AFTER 72H, AND QUICKLY CROSS THE ISLAND, AND REEMERGE INTO THE MOZAMBIQUE CHANNEL BY 120H. ANALYSIS OF RECENT MICROWAVE IMAGERY SUGGESTS EYEWALL REPLACEMENT CYCLE (ERC) HAS ALREADY BEGUN OR IS IMMINENT. THE SYSTEM HAS THUS LIKELY REACHED ITS PEAK INTENSITY AND ONCE ERC BEGINS, WILL WEAKEN BY AT LEAST 15 KNOTS IF NOT A BIT MORE. NO MAJOR CHANGES IN THE SYNOPTIC ENVIRONMENT ARE ANTICIPATED AND AFTER THE ERC COMPLETES WITHIN 12 TO 18 HOURS, RE-INTENSIFICATION IS EXPECTED, TO A SECOND PEAK OF 125 KNOTS/CAT 4 US PRIOR TO LANDFALL. THE SYSTEM WILL DRAMATICALLY WEAKEN AS IT CROSSES OVER THE RUGGED TERRAIN 2000 METER HEIGHTS OF CENTRAL MADAGASCAR, AND IS EXPECTED TO EMERGE INTO THE MOZAMBIQUE CHANNEL AS A 60 KNOT CYCLONE.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A RAPIDLY INTENSIFYING SYSTEM, HAVING DEVELOPED A 28KM EYE OVER THE PREVIOUS SIX TO TWELVE HOURS. A SERIES OF MICROWAVE IMAGERY BETWEEN A 012140Z AMSR AND A 020036Z SSMIS SHOW THE COMPACT CORE OF DEEP CONVECTION SURROUNDED BY A RAPIDLY DEVELOPING OUTER EYEWALL, INDICATIVE OF A LIKELY NEAR-TERM EYEWALL REPLACEMENT CYCLE (ERC). THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE 020036Z SSMIS 37GHZ MICROWAVE IMAGE, THE 28KM EYE FEATURE IN MET-8 EIR AND ANIMATED RADAR DATA FROM MAURITIUS, WHICH SHOWS THE EYE TO GOOD EFFECT. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE AT A HEFTY 120 KNOTS, SLIGHTLY ABOVE THE FMEE AND FIMP T6.0 ESTIMATES AND HEDGED TOWARDS THE PGTW T6.5. OBJECTIVE ADT AND SATCON ESTIMATES ARE UNREASONABLY LOW, IN THE CASE OF THE ADT DUE TO CONSTRAINTS, THOUGH THE RAW ADT IS AT T6.5 AT 020000Z. THE SYSTEM IS MOVING IN A TROCHODIAL FASHION WITH THE AVERAGE MOTION VECTOR TOWARDS THE SOUTHWEST. ANALYSIS REVEALS AN OVERALL FAVORABLE ENVIRONMENT WITH LOW TO MODERATE VERTICAL WIND SHEAR (VWS), WARM (28C) SSTS AND STRONG RADIAL OUTFLOW WITH AN ENHANCED OUTFLOW CHANNEL TO THE NORTH.

MODEL DISCUSSION: DETERMINISTIC AND ENSEMBLE GUIDANCE, WITH THE EXCEPTION OF THE NAVGEM TRACKER, ARE IN GOOD AGREEMENT THROUGH THE DURATION OF THE FORECAST PERIOD. THE JTWC TRACK REMAINS CONSISTENT WITH THE PREVIOUS FORECAST, AND LIES ROUGHLY ALONG THE NORTHERN SIDE OF THE GUIDANCE PACKAGE, NEAR THE CONSENSUS MEAN WITH HIGH CONFIDENCE. WITH THE EXCEPTION OF THE DECAY SHIPS, ALL OTHER INTENSITY MEMBERS, IN PARTICULAR THE HWRF AND COAMPS-TC MESOSCALE MODELS, SUGGEST VARYING DEGREES OF NEAR-TERM WEAKENING IN RESPONSE TO THE LIKELY EYE WALL REPLACEMENT CYCLE (ERC), FOLLOWED BY RENEWED INTENSIFICATION. THE JTWC FORECAST TRACKS THE HWRF CLOSELY THROUGH 36H, THEN GOES ABOUT 10 KNOTS HIGHER THAN THE HIGHEST GUIDANCE THROUGH LANDFALL AND THEN ONCE AGAIN TRACKS THE HWRF AFTER 96H. CONFIDENCE IS LOW TO MEDIUM IN THE INTENSITY FORECAST DUE TO THE UNCERTAINTY SURROUNDING THE TIMING OF ERC AND THE AMOUNT OF THE RESULTING WEAKENING.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC 09P CONTINUES TO STRUGGLE AND AT PRESENT, INDEPENDENT OF THE RECENT FLARE UP IN CONVECTIVE ACTIVITY, THE MID-LEVEL DRY AIR INDICATED IN THE HWRF MODEL CROSS-SECTIONS AND THE CONVERGENT FLOW ALOFT AT THE BASE OF A DEEP UPPER LOW, ARE DEFEATING THE SYSTEM. THE SYSTEM IS TRACKING WEST ALONG THE SOUTHERN SIDE OF A BROAD NEAR EQUATORIAL RIDGE (NER) TO THE NORTH AND IS EXPECTED TO CONTINUE THIS GENERAL MOTION FOR THE NEXT 24 HOURS. AFTER 24H THE SYSTEM WILL GRADUAL TURN AND ACCELERATE ONTO A SOUTHWESTWARD TRACK ALONG THE STRENGTHENING GRADIENT BETWEEN THE NER AND A STRONG MID-LATITUDE TROUGH TO THE SOUTH. LATE IN THE FORECAST PERIOD, THE SYSTEM IS EXPECTED TO BEGIN TURNING MORE SHARPLY POLEWARD IN RESPONSE TO THE DEEPENING MID-LATITUDE TROUGH. INTENSITY IS EXPECTED TO REMAIN STEADY AT 30 KNOTS FOR THE NEXT 24 TO 36 HOURS AS THE DRY AIR AND UNFAVORABLE OUTFLOW CONTINUE TO INFLUENCE THE SYSTEM. AFTER 36H THE SYSTEM IS EXPECTED TO MOVE INTO AN INCREASINGLY FAVORABLE REGION WITH INCREASED MOISTURE CONTENT, LOW VERTICAL WIND SHEAR (VWS) AND IMPROVED DIVERGENT EQUATORWARD OUTFLOW, WHICH WILL ALLOW FOR A PERIOD OF SLOW BUT STEADY INTENSIFICATION TO A PEAK OF 55 KNOTS BY 96H. SLOW WEAKENING IS EXPECTED BY 120H AS THE SYSTEM ENCOUNTERS INCREASING SHEAR AND MOVES OVER COOLER WATERS.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: JTWC ASSESSES THAT TC 09P HAS DROPPED BELOW THE 35 KNOT WARNING THRESHOLD. HOWEVER, AS THE SYSTEM IS ANTICIPATED TO REDEVELOP WITHIN THE NEXT 48 HOURS, JTWC WILL CONTINUE ISSUING WARNINGS ON THIS SYSTEM. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A DISORGANIZED AND WEAK CIRCULATION, CENTERED JUST EAST OF AN AREA OF FLARING CONVECTIVE ACTIVITY. ANALYSIS OF RECENT ANIMATED VISIBLE IMAGERY, A 012325Z GPM 37GHZ MICROWAVE IMAGE AND A 012230Z ASCAT-B BULLSEYE PASS FORCED A RELOCATION OF THE INITIAL POSITION, APPROXIMATELY 110KM NORTHWEST OF THE EXPECTED POSITION AT THE 020000Z HOUR. IN LIGHT OF THE NEW DATA, THE CURRENT INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE. THE INITIAL INTENSITY OF 30 KNOTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE PREVIOUSLY MENTIONED ASCAT-B PASS WHICH SHOWED 25-30 KNOT WINDS IN A BROAD ARC ON THE NORTHERN SIDE OF THE SYSTEM, AND LESS THAN 20 KNOTS ON THE SOUTHERN SIDE. NO AGENCIES ARE CURRENTLY FIXING ON THE SYSTEM, THOUGH THE OBJECTIVE ADT AND SATCON REMAIN UNREASONABLY HIGH BASED ON THE OVERALL STRUCTURE AND THE SCATTEROMETER DATA. THE SYSTEM CONTINUES TO TRACK THROUGH A MARGINALLY UNFAVORABLE ENVIRONMENT WITH LOW VWS AND WARM SSTS OFFSET BY MID-LEVEL DRY AIR AND AND CONVERGENT FLOW ALOFT.

MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS FAIR AGREEMENT THROUGH THE MAJORITY OF THE FORECAST, BUT DISPLAYS INCREASING UNCERTAINTY IN THE EXTENDED RANGE. SPREAD IS A MARGINAL 195KM AT 72H, BUT INCREASES TO 575KM BY 120H. ALL MODELS AGREE ON THE GENERAL TRACK INCLUDING THE TURN POLEWARD AT 120H, BUT DIFFER ON THE SHARPNESS OF THE TURN. UKMET AND EGRR REMAIN THE POLEWARD OUTFLOW WHILE NAVGEM AND GFS REMAIN MARKING THE EQUATORWARD BOUNDARY OF THE ENVELOPE. THE JTWC TRACK LIES JUST NORTH OF THE CONSENSUS MEAN, BUT DUE TO THE RELOCATION OF THE INITIAL POSITION AND THE INDUCED UNCERTAINTY THE BRINGS, CONFIDENCE IS LOW. INTENSITY GUIDANCE HAS COME INTO BETTER AGREEMENT, WITH ALL MEMBERS INDICATING A FLAT INTENSITY OR SLIGHT INTENSIFICATION IN THE NEAR-TERM, FOLLOWED BY SLOW STEADY INTENSIFICATION THEREAFTER. THE JTWC FORECAST LIES SLIGHTLY BELOW THE HWRF PEAK OF 60 KNOTS, BUT ABOVE THE MAJORITY OF THE GUIDANCE AFTER 36H. CONFIDENCE IS MEDIUM IN THE NEAR-TERM BECOMING LOW IN THE EXTENDED FORECAST.