140900Z POSITION NEAR 17.4S 58.6E. TROPICAL CYCLONE (TC) 05S (BANSI), LOCATED APPROXIMATELY 181 NM NORTH-NORTHEAST OF PORT LOUIS, MAURITIU, HAS TRACKED EAST- NORTHEASTWARD AT 03 KNOTS OVER THE PAST SIX HOURS. RECENT ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS SPIRAL BANDING WRAPPING INTO A 12-NM CLOUD-FILLED EYE. THE CURRENT POSITION IS BASED ON THE MSI LOOP WITH HIGH CONFIDENCE. A 140523Z METOP-B MICROWAVE IMAGE GIVES HINT OF A POSSIBLE EYE-WALL REPLACEMENT CYCLE, WITH A LIMITED MOAT VISIBLE IN THE MICROWAVE. AS SUCH, THE INITIAL INTENSITY HAS BEEN DECREASED TO 90 KNOTS TO REFLECT THE WEAKENING TREND DURING THE CYCLE. UPPER-LEVEL ANALYSIS INDICATES TC 05S REMAINS IN FAVORABLE ENVIRONMENT WITH LOW (05 TO 10 KNOTS) VERTICAL WIND SHEAR (VWS) AND AGGRESSIVE POLEWARD OUTFLOW. TC BANSI IS CURRENTLY TRACKING ALONG THE SOUTHERN PERIPHERY OF A WEAKENING AND ELONGATING NEAR-EQUATORIAL RIDGE (NER). SLOW OR NEAR QUASI- STATIONARY MOVEMENT IS EXPECTED OVER THE NEXT 36 HOURS DUE TO A WEAK STEERING ENVIRONMENT BETWEEN THE NER TO THE NORTH AND A DEVELOPING SUBTROPICAL RIDGE (STR) TO THE EAST. OVER THE NEXT 48 HOURS, SLIGHTLY FAVORABLE CONDITIONS ARE EXPECTED TO PERSIST ALLOWING THE SYSTEM TO SLOWLY REGAIN SOME OF ITS FORMER INTENSITY, LEADING TO A PEAK OF 115 KNOTS BEFORE STARTING TO WEAKEN. BEYOND TAU 48, TC 05S IS FORECAST TO TRACK SOUTHEASTWARD AND ACCELERATE UNDER THE STEERING INFLUENCE OF THE STRENGTHENING STR. TC BANSI WILL CONTINUE TO WEAKEN AS VWS INCREASES AND OCEAN HEAT CONTENT DECREASES ALONG ITS EXPECTED TRACK. AVAILABLE MODEL GUIDANCE IS IN OVERALL GOOD AGREEMENT LENDING TO HIGH CONFIDENCE IN THE JTWC TRACK FORECAST WHICH IS POSITIONED CLOSE TO MULTI-MODEL CONSENSUS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 140600Z IS 30 FEET.
In a previous update I asked weather observers to keep an eye on System 93 in the Mozambique channel. This system already dumped heavy rain in parts of Mozambique and Malawi resulting in flash flooding. Thousands had to literally run for their lives while others were't so lucky to escape.
System 93S has no developed further. Although most people are watching Tropical Cyclone Bansi in the Southern Indian Ocean, a new tropical low pressure area has intensified about 489 nautical miles west-northwest of Antananarivo, Madagascar, in the Mozambique Channel. System 93S is actually straddling the coast of Mozambique. System 93S is centered near 17.7 south and 37.9 east. Satellite imagery shows that there is flaring "deep convection" - rising air that forms thunderstorms that make up a tropical cyclone - associated with this slowly-consolidating area of low pressure. The warm sea surface temps in the Mozambique Channel will help the tropical low develop. Currently maximum sustained winds are estimated between 20 to 25 knots. Despite the good conditions, at least over the next day, this system has a low chance for development into a tropical depression, but keep an eye on it.
- JTWC, SAT24 and NASA
