TCFA for INVEST 93S// TC 06S(ANGGREK) becoming ET after peak intensity at CAT 4 US// INVEST 93W// 3015utc

JTWC IS ISSUING IS ISSUING 12HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS TC 06S. 3HOURLY SATELLITE BULLETINS ARE ISSUED ON INVEST 93S.

THE AREA OF CONVECTION (INVEST 93S) PREVIOUSLY LOCATED NEAR 17.6S 64.4E IS NOW LOCATED NEAR 18.8S 64.5E, APPROXIMATELY 81 NM NORTHEAST OF PORT MATHURIN. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A QUICKLY CONSOLIDATING LOW LEVEL CIRCULATION CENTER (LLCC) WITH DEEP CONVECTION DISPLACED SLIGHTLY WEST OF THE LLCC. A 300536Z ASCAT METOP-C SCATTEROMETER PARTIAL PASS SHOWS AN OVAL SHAPED LLCC WITH STRONGER WINDS NOW WRAPPING AROUND THE SOUTHERN PERIPHERY OF CIRCULATION. UPPER-LEVEL ANALYSIS REVEALS A FAVORABLE ENVIRONMENT WITH LOW TO MODERATE VWS (15 TO 20 KNOTS ), SEA SURFACE TEMPERATURES (SST) OF 28-29C, A STRONG 850MB VORTICITY SIGNATURE, AND GOOD POLEWARD OUTFLOW ALOFT. GLOBAL MODELS ARE IN AGREEMENT THAT 93S WILL CONTINUE TRACKING SOUTHEASTWARD WITH CONTINUOUS DEVELOPMENT AND INTENSIFICATION OVER THE NEXT 12-24 HOURS. SOUTHEASTWARD AS IT MOVES OVER FAVORABLE CONDITIONS AND INTENSIFIES OVER THE NEXT 24 TO 36 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 28 TO 33 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 IS UPGRADED TO HIGH.

GLOBAL MODELS ARE IN AGREEMENT THAT 93S WILL CONTINUE TRACKING SOUTHEASTWARD WITH CONTINUOUS DEVELOPMENT AND INTENSIFICATION OVER THE NEXT 12-24 HOURS. SOUTHEASTWARD AS IT MOVES OVER FAVORABLE CONDITIONS AND INTENSIFIES OVER THE NEXT 24 TO 36 HOURS.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC 06S IS FORECAST TO CONTINUE TO ACCELERATE TOWARDS THE SOUTHEAST ALONG THE TIGHT GRADIENT BETWEEN THE STR TO THE EAST-NORTHEAST AND A STRONG FRONTAL BOUNDARY LURKING ABOUT 100NM SOUTH OF THE SYSTEM. TC 06S IS ALREADY BEING SHEARED APART BY 35 KNOTS OF NORTHWESTERLY SHEAR AND BEING ENGULFED BY DRY MID-LEVEL AIR BEING USHERED IN ALONG THE SHEAR VECTOR. MODEL-BASED PHASE SPACE DIAGRAMS DEPICT A RAPID EXTRA-TROPICAL TRANSITION (ETT), STARTING WITHIN THE NEXT 12 HOURS AND COMPLETING WITHIN THE NEXT 24-36 HOURS AS THE SYSTEM EMBEDS ITSELF INTO THE FRONTAL BOUNDARY, MOVES UNDER AN EXTREMELY STRONG UPPER-LEVEL JET MAX AND MOVES OVER RELATIVELY COLD WATERS LESS THAN 21C. WHILE THE SYSTEM UNDERGOES ETT, IT WILL RAPIDLY WEAKEN, BUT IS EXPECTED TO COMPLETE TRANSITION AS A STORM-FORCE LOW PRESSURE SYSTEM.

MODEL DISCUSSION: DETERMINISTIC TRACK GUIDANCE IS IN VERY GOOD AGREEMENT ON THE SOUTHEASTWARD TRACK, THOUGH AS EXPECTED, ALONG-TRACK SPREAD INCREASES SHARPLY AS THE SYSTEM UNDERGOES ETT. THE JTWC TRACK IS CONSISTENT WITH THE CONSENSUS MEAN WITH HIGH CONFIDENCE. INTENSITY GUIDANCE IS ALSO IN GOOD AGREEMENT, WITH ALL MODELS SHOWING A SHARP AND RAPID WEAKENING THROUGH THE END OF THE FORECAST. THE JTWC FORECAST IS CONSISTENT WITH, THOUGH SLIGHTLY ABOVE, THE CONSENSUS MEAN WITH HIGH CONFIDENCE.