TC 11S(FREDDY) powerful CAT 4 US: 5th intensity peak possible rapidly approaching Mauritius/Réunion islands//Invests 99W/93S//1915utc

JTWC IS ISSUING 12HOURLY WARNINGS AND 3HOURLY SATELLITE BULLETINS ON TC 11S(FREDDY). 3HOURLY SATELLITE BULLETINS ARE ALSO ISSUED ON INVEST 93S.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A FAIRLY SYMMETRICAL SYSTEM WITH RELATIVELY RAGGED BANDING IN THE NORTHERN AND SOUTHERN PERIPHERIES. TC FREDDY IS SHOWING SIGNS OF A SLOWLY EXPANDING EYE WHICH INDICATES A WEAKENING TREND. A 190523Z ASCAT-B IMAGE SHOWS THE 34, 50, AND 64 KNOT WIND RADII TO BE IN A SOMEWHAT BALANCED DISTRIBUTION AROUND THE LOW LEVEL CIRCULATION CENTER (LLCC). ENVIRONMENTAL ANALYSIS INDICATES TC 11S TO BE IN FAVORABLE CONDITIONS FOR CONTINUAL TROPICAL DEVELOPMENT. THESE CONDITIONS ARE CHARACTERIZED BY CONSISTENT WESTERLY OUTFLOW ALOFT, LOW (5-10 KTS) VERTICAL WIND SHEAR (VWS), A VERY STRONG 850 MB VORTICITY SIGNATURE, AND WARM (27-28 C) SEA SURFACE TEMPERATURES (SST). THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE ABOVE MENTIONED MSI AND SCATTEROMETRY IMAGES. THE INITIAL INTENSITY OF 130 KTS IS ASSESSED WITH MEDIUM CONFIDENCE SET SLIGHTLY HIGHER THAN MULTI-AGENCY AND AUTOMATED DVORAK ESTIMATES.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC FREDDY CONTINUES ITS WEST-SOUTHWESTWARD TRACK AS IT TRANSITS THE NORTHEASTERN PERIPHERY OF THE STR TO THE SOUTHEAST. COPIOUS AMOUNTS OF DRY AIR WILL CONTINUE TO SURROUND THE SYSTEM, HOWEVER, TC FREDDY WILL STAY COCOONED IN ITS OWN MOISTURE POCKET THROUGHOUT ITS FORECAST TRACK. THE SYSTEM WILL CONTINUE ITS WEST-SOUTHWESTWARD TRAJECTORY AND GRADUALLY DECREASE IN INTENSITY TO 105 KNOTS AS IT MAKES ITS APPROACH TO THE EAST COAST OF MADAGASCAR SHORTLY AFTER TAU 48. TC 11S IS FORECAST TO FURTHER DECREASE IN INTENSITY TO 45 KNOTS BY TAU 72 AS IT TRANSITS ACROSS THE MOUNTAINOUS TERRAIN OF SOUTHERN MADAGASCAR. BY TAU 96, THE SYSTEM WILL BE IN ANOTHER FAVORABLE ENVIRONMENT OVER THE MOZAMBIQUE CHANNEL AND RE-INTENSIFY TO 55 KNOTS AS A RESULT. BY TAU 120, TC FREDDY WILL APPROACH THE MOZAMBIQUE COAST SOUTH OF BEIRA AND DECREASE TO 45 KNOTS DUE TO LAND INTERACTION.

MODEL DISCUSSION: THE JTWC MODEL TRACK CONSENSUS REMAINS IN TIGHT AGREEMENT WITH A GRADUAL SPREAD TO 70 NM BY TAU 48. AFTERWARDS, THE SPREAD INCREASES TO 240 NM BY TAU 120 AS THE MEMBERS DISAGREE WITH THE TRAJECTORY OVER THE MOZAMBIQUE CHANNEL. GFS DETERMINISTIC AND ENSEMBLE GUIDANCE TAKES TC 11S ON A MORE WEST-NORTHWESTWARD TRACK WHILE CROSSING OVER THE MOZAMBIQUE CHANNEL, WHEREAS THE OTHER MEMBERS KEEP THE SYSTEM ON A WEST-SOUTHWESTWARD TRACK. THE FORECAST TRACK IS SET SLIGHTLY TO THE RIGHT OF CONSENSUS AFTER TAU 72 TO ACCOUNT FOR THE OFFSET OF THE GFS GUIDANCE. BECAUSE OF THIS, THE JTWC FORECAST TRACK IS PLACED WITH HIGH CONFIDENCE UP TO TAU 72, THEN MEDIUM CONFIDENCE THEREAFTER. THE INTENSITY GUIDANCE IS ALSO IN GOOD AGREEMENT WITH THE EXCEPTION OF GFS WHICH DECREASES THE INTENSITY WELL BEYOND THE OTHER CONSENSUS MEMBERS. THE JTWC INTENSITY FORECAST IS SET WITH MEDIUM CONFIDENCE.

THE AREA OF CONVECTION (INVEST 99W) PREVIOUSLY LOCATED NEAR 7.2N 129.3E IS NOW LOCATED NEAR 11.9N 124.4E, APPROXIMATELY 255 NM SOUTHEAST OF MANILA, PHILIPPINES. ANIMATED MULTISPECTRAL IMAGERY (MSI) DEPICT A BROAD AREA OF DISORGANIZED CONVECTION OVER THE CENTRAL PHILIPPINE ISLANDS. A 190152Z ASCAT-B PASS SHOW A REGION OF GENERAL CYCLONIC TURNING DISRUPTED BY NUMEROUS ISLANDS. ENVIRONMENTAL ANALYSIS REVEALS THAT 99W IS IN A MARGINALLY FAVORABLE REGION FOR DEVELOPMENT DUE TO HIGH (25-30KT) VWS, OFFSET BY GOOD WESTWARD OUTFLOW AND WARM (26-27C) SSTS. THE PLACEMENT OF INVEST 99W IS DIFFICULT DUE TO THE LOW LEVEL CIRCULATION ESTIMATED TO BE OVER THE CENTRAL PHILIPPINE ISLANDS. LAND INTERACTION IS PLAYING A ROLE IN LIMITING CONSOLIDATION AT THIS TIME. DETERMINISTIC AND ENSEMBLE MODEL GUIDANCE INDICATE INVEST 99W WILL TRANSIT NORTH AND BECOME BETTER ORGANIZED IN APPROXIMATELY 18-24 HOURS OVER THE WATERS NORTHEAST OF LAMON BAY. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1007 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS REMAINS MEDIUM.

DETERMINISTIC AND ENSEMBLE MODEL GUIDANCE INDICATE INVEST 99W WILL TRANSIT NORTH AND BECOME BETTER ORGANIZED IN APPROXIMATELY 18-24 HOURS OVER THE WATERS NORTHEAST OF LAMON BAY.