TS 27W(NYATOH): rapid intensification likely next 48hours//Invest 94W: intensification expected by 48hours/Invest 92S on the map, 30/09utc

JTWC IS ISSUING 6HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON TS 27W(NYATOH).

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TROPICAL STORM 27W WILL TRACK NORTHWESTWARD OVER THE NEXT 24 HOURS BEFORE BEGINNING A MORE NORTHWARD TRACK AS IT ROUNDS THE SUBTROPICAL RIDGE AXIS FROM 36H TO 48H. AFTER 48H, THE SYSTEM WILL BEGIN TO ACCELERATE NORTHEASTWARD UNDER THE INFLUENCE OF A DEEP MID-LATITUDE TROUGH PASSING TO THE NORTH. DUE TO INCREASINGLY ROBUST OUTFLOW PAIRED WITH HIGHLY FAVORABLE OCEAN HEAT CONTENT AND LOW VERTICAL WIND SHEAR, TS 27W WILL UNDERGO A PERIOD OF RAPID INTENSIFICATION FROM 06H TO 48H. THE CURRENT FORECAST PEAKS THE INTENSITY AT 100 KNOTS/CAT 3 AT 48H, BUT IT IS LIKELY TO REACH 110 KNOTS/CAT 3 SOMETIME AROUND 60H BEFORE INCREASING VERTICAL WIND SHEAR FROM THE MID-LATITUDE TROUGH TO THE NORTH BEGINS TO WEAKEN THE SYSTEM TO 95 KNOTS/CAT 2 BY 72H. IN ADDITION TO WEAKENING THE SYSTEM, THE VERTICAL WIND SHEAR FROM THE MID-LATITUDE TROUGH IS EXPECTED INITIATE A DECOUPLING PROCESS OF THE CIRCULATION. THIS IS EXPECTED TO OCCUR AFTER 96H WITH THE REMAINING LOW LEVEL CIRCULATION, NOW UNDER THE INFLUENCE OF LOW LEVEL STEERING FEATURES, BEING DRIVEN SOUTHWESTWARD.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A RAPIDLY CONSOLIDATING SYSTEM WITH ROBUST RADIAL OUTFLOW AND A CLEARLY DEFINED LOW LEVEL CIRCULATION CENTER WHICH LENDS HIGH CONFIDENCE TO THE INITIAL POSITION. THE INITIAL INTENSITY OF 40 KNOTS IS HEDGED SLIGHTLY HIGHER THAN PGTW AND KNES DVORAK ESTIMATES TO ACCOUNT FOR THE POSSIBLE START OF A PERIOD OF RAPID INTENSIFICATION WHICH IS FURTHER DISCUSSED IN THE FORECAST DISCUSSION.

MODEL DISCUSSION: IN REGARDS TO FORECAST INTENSITY, BOTH DETERMINISTIC AND ENSEMBLE MODELS ARE GENERALLY IN GOOD AGREEMENT AS FAR A THE TREND OF INTENSIFICATION. LATEST RUNS DEPICT A PERIOD OF MODERATE TO RAPID INTENSIFICATION UP TO 48H WITH PEAK INTENSITY AROUND 60H AND A MODERATE TO RAPID WEAKENING FOR THE REMAINDER OF THE FORECAST. THE RANGE OF PEAK INTENSITY VARIES WITH GFS PEAKING AT ABOUT 80 KTS AND CTCI PEAKING NEAR 120 KTS. THE FORECAST INTENSITY IS THEREFORE BASED OFF OF THE CONSENSUS. IN REGARDS TO FORECAST TRACK, THE MODELS SPLIT BETWEEN TWO POSSIBLE SCENARIOS. THE GFS DETERMINISTIC, GFS ENSEMBLE, EGRR, AND AFUM DEPICT A DECOUPLING SCENARIO AROUND 96H, WHICH THE FORECAST TRACK CURRENTLY REFLECTS. ALTERNATIVELY, THE ECMWF DETERMINISTIC, ECMWF ENSEMBLE, AND NVGM DEPICT A SCENARIO WHERE THE SYSTEM IS PULLED NORTHEASTWARD AFTER 96H IN THE WAKE OF THE MID-LATITUDE TROUGH AND DISSIPATES OR UNDERGOES EXTRATROPICAL TRANSITION.

THE AREA OF CONVECTION (INVEST 94W) PREVIOUSLY LOCATED NEAR 7.9N 106.0E IS NOW LOCATED NEAR 9.3N 101.0E, APPROXIMATELY 330 KM EAST-NORTHEAST OF PHUKET, THAILAND. ANIMATED ENHANCED MULTISPECTRAL SATELLITE IMAGERY (MSI) AND A 300222Z PARTIAL ASCAT METOP-B PASS REVEALS A FAIRLY DISORGANIZED LOW-LEVEL CIRCULATION — WITH A 292358Z SSMIS MICROWAVE IMAGE DEPICTING MOST OF THE CONVECTION DISPLACED TO THE SOUTHEAST. ENVIRONMENTAL ANALYSIS INDICATES THAT INVEST 94W IS IN A MARGINALLY FAVORABLE ENVIRONMENT DEFINED BY GOOD POLEWARD OUTFLOW, WARM (29-30C) SEA SURFACE TEMPERATURES, BUT OFFSET BY MODERATE TO HIGH (20-25KT) VWS. GLOBAL MODELS ARE IN AGREEMENT INVEST 94W WILL TRACK OVER THAILAND AND DECREASE IN INTENSITY BUT WILL REORGANIZE IN THE ANDAMAN SEA BY 48H. AFTERWARDS, THE SYSTEM WILL TRACK WEST-NORTHWESTWARD AND INTENSIFY IN THE BAY OF BENGAL, AND THEN RECURVE TO THE NORTH- NORTHEAST TRACKING NEAR THE EASTERN COAST OF INDIA. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1006 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS MEDIUM.

GLOBAL MODELS ARE IN AGREEMENT INVEST 94W WILL TRACK OVER THAILAND AND DECREASE IN INTENSITY BUT WILL REORGANIZE IN THE ANDAMAN SEA BY 48H. AFTERWARDS, THE SYSTEM WILL TRACK WEST-NORTHWESTWARD AND INTENSIFY IN THE BAY OF BENGAL, AND THEN RECURVE TO THE NORTH- NORTHEAST TRACKING NEAR THE EASTERN COAST OF INDIA.

AN AREA OF CONVECTION (INVEST 92S) HAS PERSISTED NEAR 7.1S 101.8E, APPROXIMATELY 475 KM WEST-SOUTHWEST OF JAKARTA, INDONESIA. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS BROAD CONVECTION SURROUNDING A PARTIALLY EXPOSED LOW LEVEL CIRCULATION (LLC). A RECENT SCATTEROMETER PASS SHOWS A DEFINED CIRCULATION WITH 20 KNOT WINDS OFFSET TO THE NORTH. ENVIRONMENTAL ANALYSIS INDICATES THAT THE SYSTEM IS IN A MARGINALLY FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH STRONG EQUATORWARD OUTFLOW ALOFT AND WARM (28-29C) SEA SURFACE TEMPERATURES, OFFSET BY HIGH (25-30KT) VERTICAL WIND SHEAR. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 92S WILL CONSOLIDATE AND TRACK SOUTHEASTWARD OVER THE NEXT 48 HOURS, WITH GFS AND ITS ENSEMBLE BEING THE MOST AGGRESSIVE. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1006 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS LOW.

30/0845UTC.