TC 04S(CHIDO) to intensify to Typhoon Intensity within 12/24h gradually approaching Northern MADAGASCAR//INVEST 93S//INVEST 91S//INVEST 94S//1009utc

JTWC IS ISSUING 12HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON 04S(CHIDO) AND 3OURLY SATELLITE BULLETIN ON 91S,93S,94S AND 90B.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL CYCLONE O4S (CHIDO) WITH AN IMPROVED APPEARANCE, BUT STILL WITH AN ASYMMETRICAL WIND FIELD DUE TO THE SLIGHTLY VERTICALLY TILTED VORTEX AND EASTERLY SHEAR. STRONGER WINDS CAN BE SEEN ALONG THE WESTERN PERIPHERY OF THE LOW-LEVEL CIRCULATION CENTER (LLCC). PERSISTENT BURSTS OF DEEP CONVECTION OBSCURE THE LLCC, WITH A WARM SPOT RECENTLY APPEARING OVER THE CENTER RIGHT AROUND 0600Z. THE OUTFLOW PATTERN HAS IMPROVED AND BECOME MORE RADIAL OVER THE PAST 6 HOURS WITH CIRRUS FILAMENTS EXTENDING OUTWARD IN ALL DIRECTIONS. ENVIRONMENTAL ANALYSIS INDICATES A MARGINALLY FAVORABLE ENVIRONMENT FOR DEVELOPMENT CHARACTERIZED BY THE MODERATE RADIAL OUTFLOW ALOFT AND WARM (28-29 C) SEA SURFACE TEMPERATURES, OFFSET BY THE MODERATE TO HIGH (20-25 KTS) EASTERLY VERTICAL WIND SHEAR. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE OBSCURED LLCC IN ANIMATED MSI. THE INITIAL INTENSITY OF 50 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK AND OBJECTIVE INTENSITY ESTIMATES LISTED BELOW.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: INCREASED THE PEAK INTENSITY FROM 60 KTS TO 80 KTS AT TAU 48. FORECAST DISCUSSION: TC 04S IS FORECAST TO CONTINUE TRACKING WESTWARD ALONG THE NORTHERN PERIPHERY OF THE STR THROUGH TAU 48. AFTER TAU 48, THE RIDGE TO THE SOUTH BUILDS AND THE SYSTEM BEGINS TO TRACK MORE WEST-SOUTHWESTWARD ALONG THE NORTHEASTERN PERIPHERY OF THE RIDGE. THE WEST-SOUTHWESTWARD TRACK WILL THEN CONTINUE THROUGH THE REMAINDER OF THE FORECAST PERIOD. JUST AFTER TAU 72, 04S IS FORECAST TO SKIRT ALONG THE NORTHERN TIP OF MADAGASCAR AS IT ENTERS THE MOZAMBIQUE CHANNEL AND APPROACHES THE COAST OF MOZAMBIQUE NEAR TAU 120. REGARDING INTENSITY, 04S IS FORECAST TO CONTINUE INTENSIFYING THROUGH TAU 48 AS IT BECOMES VERTICALLY ALIGNED. RECENT MODEL GUIDANCE HAS DEPICTED A QUICKER ONSET OF THIS ALIGNMENT, ALLOWING FOR A HIGHER PEAK INTENSITY. AFTER TAU 48, THE ENVIRONMENT WILL BEGIN TO WORSEN AS EASTERLY VERTICAL WIND SHEAR INCREASES. THIS WILL CAUSE 04S TO START A WEAKENING TREND WHICH WILL PERSIST THROUGHOUT THE REMAINDER OF THE FORECAST PERIOD. ADDITIONALLY, AS THE SYSTEM TRACKS ACROSS THE NORTHERN TIP OF MADAGASCAR TERRAIN INTERACTION WILL AID IN THE WEAKENING OF THE VORTEX. AS A RESULT, 04S IS FORECAST TO DROP TO AROUND 35 KTS AT TAU 120, JUST OFF THE COAST OF NORTHERN MOZAMBIQUE.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT REGARDING THE TRACK OF 04S THROUGH TAU 72, WITH A 115 NM CROSS-TRACK SPREAD AT THAT TIME. AFTER TAU 72, MODELS BEGIN TO DIVERGE. NAVGEM AND GALWEM TAKE THE SYSTEM FURTHER SOUTH INTO MADAGASCAR, WHICH CAUSES THEM TO TRACK THE VORTEX MUCH FURTHER SOUTHWARD WITHIN THE MOZAMBIQUE CHANNEL THAN THE REMAINDER OF GUIDANCE. THE JTWC TRACK FORECAST IS PLACED CLOSER TO THE MAIN GROUPING WITH HIGH CONFIDENCE THROUGH TAU 72 AND MEDIUM CONFIDENCE THEREAFTER. INTENSITY GUIDANCE IS IN GOOD AGREEMENT WITH THE EXCEPTION OF THE MAJOR OUTLIER, HAFS-A. HAFS-A SUGGESTS A PEAK INTENSITY OF AROUND 120 KTS AT TAU 48, WHILE THE REMAINDER OF GUIDANCE SUGGESTS A PEAK OF AROUND 65-85 KTS. THE JTWC INTENSITY FORECAST IS PLACED NEAR MAJORITY THROUGHOUT THE FORECAST PERIOD WITH OVERALL MEDIUM CONFIDENCE.

THE AREA OF CONVECTION (INVEST 93S) PREVIOUSLY LOCATED NEAR 16.5S 117.6E IS NOW LOCATED NEAR 15.2S 115.7E, APPROXIMATELY 430 NM NORTHEAST OF LEARMONTH. ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A BROAD AREA OF FLARING CONVECTION, WITH A CONSOLIDATING LOW LEVEL CIRCULATION CENTER (LLCC). ADDITIONALLY, A 091038Z GMI 89GHZ SATELLITE IMAGERY REVEALS A PARTIALLY EXPOSED CIRCULATION, WITH FRAGMENTED FORMATIVE BANDING SLOWLY CONSOLIDATING AROUND THE LLCC. ENVIRONMENTAL ANALYSIS REVEALS THAT INVEST 93S IS IN A FAVORABLE ENVIRONMENT FOR FURTHER DEVELOPMENT WITH WARM (29-30C) SEA SURFACE TEMPERATURES, GOOD EQUATORWARD OUTFLOW ALOFT, AND LOW (10-15 KTS) VERTICAL WIND SHEAR. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT INVEST 93S WILL GENERALLY TRACK SOUTHWEST WARD OVER THE NEXT 48 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 28 TO 33 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS MEDIUM.

GLOBAL MODELS ARE IN GOOD AGREEMENT THAT INVEST 93S WILL GENERALLY TRACK SOUTHWEST WARD OVER THE NEXT 48 HOURS.

THE AREA OF CONVECTION (INVEST 91S) PREVIOUSLY LOCATED NEAR 8.5S 100.2E IS NOW LOCATED NEAR 10.4S 97.4E, APPROXIMATELY 107 NM NORTH-NORTHEAST OF COCOS ISLAND. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY CONTINUES TO DEPICT INVEST 91S WITH A FULLY EXPOSED LLCC WITH PERSISTENT CONVECTION SHEARED TO THE WEST OF THE LLCC. A 081413Z ASCAT METOP-B 50 KM PARTIAL PASS REVEALS 15-20 KT WINDS TO THE NORTH AND SOUTH OF THE LLCC. AS FOR THE ENVIRONMENTAL ANALYSIS, 91S IS IN A MARGINAL ENVIRONMENT FOR FURTHER DEVELOPMENT WITH WARM SEA SURFACE TEMPERATURES OF 29-30C OFFSET BY WEAK POLEWARD UPPER-LEVEL OUTFLOW AND MODERATE TO HIGH VERTICAL WIND SHEAR OF 25-30 KT. LASTLY, GLOBAL DETERMINISTIC MODELS CONTINUE TO SHOW THE SYSTEM REMAINING NEARLY QUASI-STATIONARY, WHILE BACKING OFF ON THE DEVELOPMENT ODDS FOR 91S. GLOBAL DETERMINISTIC GUIDANCE NOW SUGGESTS THE CIRCULATION IS UNLIKELY TO DEVELOP INTO A TROPICAL CYCLONE WITHIN THE NEXT 24 TO 48 HOURS, AND ENSEMBLE GUIDANCE CONTINUES TO SHOW A DOWNWARD TREND IN THE PROBABILITIES FOR DEVELOPMENT. 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 DETERMINISTIC GUIDANCE NOW SUGGESTS THE CIRCULATION IS UNLIKELY TO DEVELOP INTO A TROPICAL CYCLONE WITHIN THE NEXT 24 TO 48 HOURS, AND ENSEMBLE GUIDANCE CONTINUES TO SHOW A DOWNWARD TREND IN THE PROBABILITIES FOR DEVELOPMENT.

THE AREA OF CONVECTION (INVEST 94S) PREVIOUSLY LOCATED NEAR 10.2S 129.9E IS NOW LOCATED NEAR 9.2S 129.7E, APPROXIMATELY 211 NM NORTH-NORTHWEST OF DARWIN. ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A BROAD AND WEAKLY DEFINED ASYMMETRIC CIRCULATION, WITH FLARING CONVECTION BEGINNING TO ORGANIZE AROUND LOW LEVEL CIRCULATION CENTER (LLCC). ENVIRONMENTAL ANALYSIS REVEALS THAT INVEST 94S IS IN A FAVORABLE ENVIRONMENT FOR FURTHER DEVELOPMENT WITH WARM (30-31C) SEA SURFACE TEMPERATURES, GOOD EQUATORWARD OUTFLOW ALOFT, AND LOW VERTICAL WIND SHEAR (10-15 KTS). GLOBAL MODELS ARE EXPECTING THE SYSTEM TO GENERALLY TRACK SOUTHWESTWARD OVER THE NEXT 48 HOURS AS THE SYSTEM CONTINUES TO INTENSIFY. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 13 TO 18 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1005 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS LOW.

GLOBAL MODELS ARE EXPECTING THE SYSTEM TO GENERALLY TRACK SOUTHWESTWARD OVER THE NEXT 48 HOURS AS THE SYSTEM CONTINUES TO INTENSIFY.