TC 17S(FILIPO) peaked near BEIRA/MOZ to peak again when exiting land//TC 18S to intensify next 5 days//INVEST 93P//INVEST 92P// 1200utc

JTWC IS ISSUING 6HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON TC 18S. JTWC IS ISSUING 12HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON TC 17S.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC 17S (FILIPO) IS FORECAST TO CONTINUE TO TRACK TOWARDS THE EAST COAST OF MOZAMBIQUE OVER THE NEXT FEW HOURS, MAKING LANDFALL BY TAU 12. WHILE OVER LAND, THE SYSTEM IS EXPECTED TO ROUND THE PERIPHERY OF AN STR OVER THE SOUTHERN MOZAMBIQUE CHANNEL BEFORE COMING BACK OUT OVER LAND AROUND TAU 36. TC FILIPO WILL CONTINUE TO TRACK SOUTHEAST WHILE UNDERGOING A BRIEF PERIOD OF SUBTROPICAL TRANSITION (STT) BETWEEN TAU 16 AND 18 BEFORE INTERACTING WITH A STRONG JET MAXIMUM TO THE SOUTH. BY TAU 72, THE SYSTEM IS EXPECTED TO UNDERGO EXTRATROPICAL TRANSITION (ETT) BEFORE BECOMING ENTIRELY EXTRATROPICAL NO LATER THAN TAU 96, BUT MORE LIKELY CLOSER TO TAU 72. IN TERMS OF THE INTENSITY FORECAST, CONDITIONS REMAIN FAVORABLE IN THE SHORT TIME BEFORE LANDFALL, SO A SMALL AMOUNT OF ADDITIONAL INTENSIFICATION IS POSSIBLE PRIOR TO LANDFALL, WHICH IS NOT CAPTURED IN THE SPECIFIC FORECAST POINT. AFTER LANDFALL, THE SYSTEM IS EXPECTED TO WEAKEN OVER THE NEXT 12-36 HOURS DUE TO INTERACTION WITH TERRAIN. ONCE THE SYSTEM MOVES BACK OVER WATER, IT IS EXPECTED TO QUICKLY RECONSOLIDATE AND REINTENSIFY. VERTICAL WIND SHEAR IS EXPECTED TO INCREASE SIGNIFICANTLY BY TAU 48 AS THE SYSTEM BECOMES UNDER THE INFLUENCE OF STRONGER WESTERLY FLOW, BUT THIS WILL BE OFFSET BY ROBUST OUTFLOW INTO A 180 KNOT JET MAX TO THE SOUTH. AS A RESULT, THE SYSTEM IS EXPECTED TO RAPIDLY INTENSIFY UP TO A PEAK OF AT LEAST 65KTS BEFORE EXPERIENCING SIGNIFICANT SHEAR ABOVE 50 KNOTS AFTER TAU 72, WHICH WILL QUICKLY SHEAR THE SYSTEM APART AS IT UNDERGOES ETT.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN GOOD AGREEMENT THAT TC 17S WILL TRAVEL OVER LAND THROUGH THE NEXT 36 HOURS BEFORE CURVING SOUTHEAST THROUGH THE END OF THE FORECAST PERIOD, AS IT ROUNDS THE RIDGE WHICH SLIDES UNDERNEATH THE SYSTEM. MAXIMUM CROSS-TRACK SPREAD IS 150 NM BY TAU 96. THE JTWC INTENSITY GUIDANCE SHOWS A FAIRLY HIGH AMOUNT OF UNCERTAINTY, AS THE HWRF, COAMPS-TC, AND HAFS ALL INDICATE A PEAK INTENSITY AT OR ABOVE 70 KTS BETWEEN TAUS 60-72, SKEWING THE JTWC CONSENSUS A BIT HIGHER DURING THE SAME PERIOD. ADDITIONALLY, THE GFS, ECMWF AND COAMPS-TC ENSEMBLES ALL INDICATE A PERIOD OF RAPID INTENSIFICATION (RI) THROUGH TAU 72 AS THE SYSTEM UNDERGOES ETT.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC 18S IS FORECAST TO TRACK EAST-SOUTHEAST OVER THE NEXT 72 HOURS WHILE UNDER THE STEERING INFLUENCE OF A NER TO THE NORTH. FROM TAU 72 ONWARDS, THE TRACK BECOMES HIGHLY UNCERTAIN DUE TO SIGNIFICANT DIFFERENCES IN THE EVOLUTION OF A SUBTROPICAL RIDGE (STR) ANTICIPATED TO DEVELOP OVER CENTRAL AUSTRALIA. AS THE RIDGE DEVELOPS OVER THE CONTINENT, PRIMARILY TO THE SOUTH OF TC 18S, IT WILL TEND TO BLOCK THE SYSTEM FROM MOVING FURTHER EAST, AND TEND TO SLOW IT DOWN AS IT APPROACHES THE NORTHWEST COAST OF AUSTRALIA. A SLOW CURVE TOWARDS THE SOUTH IS EXPECTED BY THE END OF THE FORECAST PERIOD AS THE SYSTEM MOVES TOWARDS A BREAK IN THE STR. TC 18S IS FORECAST TO INTENSIFY SLOWLY BUT STEADILY OVER THE FORECAST PERIOD AS IT STRUGGLES IN THE NEAR-TERM AGAINST SIGNIFICANT EASTERLY SHEAR (20-25KTS). A FASTER RATE OF INTENSIFICATION IS EXPECTED BY THE END OF THE FORECAST AS SHEAR IS FORECAST TO WEAKEN, THOUGH THE RESTRAINED OUTFLOW ENVIRONMENT SHOULD KEEP A LID ON THE INTENSIFICATION. OTHERWISE, CONDITIONS ARE ANTICIPATED TO BE FAVORABLE AS THE ENVIRONMENT REMAINS MOIST AND SEA SURFACE TEMPERATURES ARE EXPECTED TO REMAIN BETWEEN 29-30C.

MODEL DISCUSSION: JTWC CONSENSUS TRACK MODEL GUIDANCE IS IN GOOD AGREEMENT IN THE NEAR-TERM, THAT THE STORM WILL TRACK TO THE WEST-SOUTHWEST OVER THE NEXT 36 HOURS, HOWEVER CROSS-TRACK SPREAD BEGINS TO OPEN EXPONENTIALLY BEYOND TAU 36. BY TAU 120, THE CROSS-TRACK SPREAD OPENS TO 1050NM, WITH GALWEM MARKING THE SOUTHERN EXTENT AND GFS MARKING THE NORTH. CONSENSUS GUIDANCE TENDS TO PREFER A MORE SOUTHERLY AND SLOWER ROUTE THAN GFS. LARGE DIFFERENCES IN THE STEERING MECHANISM BEYOND TAU 72 ARE REPRESENTED IN HOW THE RIDGE OVER AUSTRALIA DEVELOPS; GFS SHOWS THE RIDGE EXTENDING WESTWARD TO THE SOUTH OF THE SYSTEM, ALLOWING THE SYSTEM TO TRACK MORE EASTWARD AND CLOSER TO THE COAST NEAR BROOME. MEANWHILE THE ECMWF GUIDANCE SHOWS THE RIDGE BUILDING AS ONE LARGER RIDGE TO THE EAST, WHICH WOULD FORCE THE SYSTEM TO TURN TO THE SOUTH-SOUTHWEST MUCH SOONER IN THE FORECAST PERIOD, BEING IN GENERAL SIMILAR TO THE OTHER MODELS SUCH AS NAVGEM AND THE UKMET. THE JTWC FORECAST TRACK LIES ON THE NORTHERN EDGE OF THE GUIDANCE ENVELOPE THROUGH TAU 72, THEN REMAINS EAST OF THE CONSENSUS AND THE MAJORITY OF THE GUIDANCE, EXCEPT GFS, THROUGH TAU 120. ENSEMBLE GUIDANCE ALSO SHOWS AN EXTREME AMOUNT OF UNCERTAINTY, WITH A VERY WIDE SPREAD IN THE TRACKS. WITH SUCH HIGH UNCERTAINTY, THE JTWC FORECAST IS SET WITH LOW CONFIDENCE THROUGH THE FORECAST PERIOD. JTWC INTENSITY CONSENSUS GUIDANCE CONSISTENTLY AND STEADILY INCREASES TO 50-65KTS BY THE END OF THE FORECAST PERIOD, WITH MINIMAL SPREAD ACROSS THE GUIDANCE PACKAGE. HOWEVER, IN LIGHT OF TRACK UNCERTAINTY AND THE IMPACT OF TRACK CHANGES ON THE POTENTIAL INTENSITY, THE INTENSITY FORECAST IS SET WITH LOW CONFIDENCE.

AN AREA OF CONVECTION (INVEST 93P) HAS PERSISTED NEAR 11.0S 139.0E, APPROXIMATELY 487 NM EAST OF DARWIN. ENHANCED INFRARED IMAGERY AND A 1546Z AMSR2 39GHZ SATELLITE IMAGERY DEPICTS A BROAD AREA OF FLARING CONVECTION, WITH A WEAKLY DEFINED LLCC. UPPER-LEVEL ANALYSIS INDICATES 93P IS IN A FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH LOW (15-20KT) VERTICAL WIND SHEAR, WARM SEA SURFACE TEMPERATURES (30C), COUPLED WITH ENHANCED EQUATORWARD OUTFLOW. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 93P WILL STEADILY DEEPEN AS IT DEVELOPS UNDER FAVORABLE CONDITIONS. GLOBAL MODELS HAVE 93P ADVANCING EAST-SOUTHEAST WITHIN THE NEXT 24 HOURS, BRIEFLY TRACKING OVER LAND, THEN REINTENSIFIES AS IT MAINTAINS AN EAST- SOUTHEASTWARD TRACK INTO THE CORAL SEA OVER THE NEXT 36 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 13 TO 17 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1009 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS LOW.

GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 93P WILL STEADILY DEEPEN AS IT DEVELOPS UNDER FAVORABLE CONDITIONS. GLOBAL MODELS HAVE 93P ADVANCING EAST-SOUTHEAST WITHIN THE NEXT 24 HOURS, BRIEFLY TRACKING OVER LAND, THEN REINTENSIFIES AS IT MAINTAINS AN EAST- SOUTHEASTWARD TRACK INTO THE CORAL SEA OVER THE NEXT 36 HOURS.