TC 08S(BATSIRAI): CAT 4 US tracking North of Réunion island// TC 09P struggling under dry air// Invest 90S: now Medium,02/15utc

JTWC IS ISSUING 12HOURLY WARNINGS ON TC 08S(BATSIRAI) AND 6HOURLY WARNINGS ON TC 09P. 3HOURLY SATELLITE BULLETINS ARE ISSUED ON 08S, 09P AND INVEST 90S.

02/14UTC.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC 08S WILL TRACK GENERALLY WEST-SOUTHWESTWARD TO WESTWARD THROUGH 72H UNDER THE STEERING INFLUENCE OF THE AFOREMENTIONED SUBTROPICAL RIDGE (STR) TO THE SOUTH. OVER THE NEXT 24 HOURS, TC 08S IS FORECAST TO CONTINUE WEAKENING TO ABOUT 110 KNOTS/CAT 3 US DUE TO THE EYE-WALL REPLACEMENT CYCLE (ERC). AFTER 24H, THE SYSTEM SHOULD STRENGTHEN AS THE ERC COMPLETES AND SHOULD REINTENSIFY TO ABOUT 115 KNOTS/CAT 4 US AT 36H. THERE IS SIGNIFICANT UNCERTAINTY DURING THIS PHASE OF THE INTENSITY FORECAST. AFTER 36H, THE SYSTEM WILL WEAKEN STEADILY AS IT APPROACHES MADAGASCAR WITH RAPID WEAKENING AS THE SYSTEM TRACKS OVER THE MOUNTAINOUS TERRAIN OF MADAGASCAR. AFTER 72H, THE STR WILL SHIFT EASTWARD AND REALIGN WITH THE APPROACH OF A MIDLATITUDE MAJOR SHORTWAVE TROUGH. THIS WILL PRODUCE A WEST-SOUTHWESTWARD TURN TOWARD A BREAK IN THE STR. THE SYSTEM IS EXPECTED TO REINTENSIFY OVER THE MOZAMBIQUE CHANNEL AFTER THE FORECAST PERIOD.

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED RADAR IMAGERY FROM PORT LOUIS INDICATES AN EYEWALL REPLACEMENT CYCLE (ERC) IS UNDERWAY AS INDICATED IN THE UW-CIMSS M-PERC PRODUCT. RADAR IMAGERY CURRENTLY SHOWS THAT THE SMALL INNER EYEWALL IS ERODING AS THE OUTER EYEWALL STRENGTHENS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY INDICATES WARMING CLOUD TOPS AND WEAKENING SPIRAL BANDING. ALTHOUGH DVORAK ESTIMATES REMAIN STEADY AT T6.5 (127 KNOTS) AT 021200Z, THE SYSTEM APPEARED TO PEAK NEAR 020600-020630Z WITH UNOFFICIAL DVORAK ESTIMATES ALMOST REACHING T7.0 (140 KNOTS). HOWEVER, TC 08S IS CLEARLY WEAKENING SINCE THAT TIME DUE TO THE ONGOING ERC WITH THE 021245Z UNOFFICIAL DVORAK ESTIMATE AT T6.0 (115 KNOTS). ADT ESTIMATES PEAKED EARLIER AT 122 KNOTS (6.3) AND HAVE MAINTAINED THIS LEVEL THROUGH 021245Z. THE INITIAL INTENSITY FOR 021200Z IS ASSESSED AT 125 KNOTS/CAT 4 US BASED ON THE DVORAK ESTIMATES OF T6.5 FROM BOTH PGTW AND FMEE AS WELL AS THE CIMSS ADT ESTIMATE. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON EIR, WHICH SHOWS A ROUND 15KM EYE.

MODEL DISCUSSION: WITH THE EXCEPTION OF NAVGEM, NUMERICAL MODEL GUIDANCE IS IN TIGHT AGREEMENT THROUGH THE FORECAST PERIOD LENDING HIGH CONFIDENCE TO THE JTWC FORECAST TRACK. OVERALL, INTENSITY GUIDANCE IS IN GOOD AGREEMENT WITH MEDIUM CONFIDENCE.

FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TC 09P IS FORECAST TO TRACK EASTWARD TO EAST-SOUTHEASTWARD UNDER THE STEERING INFLUENCE OF THE NER THROUGH 72H. TC 09P WILL MAINTAIN INTENSITY AT 25 KNOTS THROUGH 24H DUE TO DRY AIR ENTRAINMENT AS WELL AS WEAK OUTFLOW ALOFT. AFTER 24H, THE SYSTEM WILL INTENSIFY SLOWLY AS POLEWARD OUTFLOW IMPROVES AND THE CORE ENVIRONMENT MOISTENS. AFTER 72H, TC 09P WILL GRADUALLY TURN SOUTHEASTWARD ALONG THE WESTERN FLANK OF A BUILDING SUBTROPICAL RIDGE (STR) TO THE EAST. THE SYSTEM WILL PEAK AT 55 KNOTS BY 96H THEN WEAKEN SLIGHTLY, HOWEVER, THIS PORTION OF THE INTENSITY FORECAST IS UNCERTAIN DUE TO POSSIBLE DRY AIR ENTRAINMENT AND SLIGHTLY COOLER SEA SURFACE TEMPERATURES (27-28C).

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A WEAK, POORLY-DISORGANIZED LOW-LEVEL CIRCULATION (LLC) WITH FLARING DEEP CONVECTION OVER THE NORTHWEST PERIPHERY. A 021240Z GMI 89GHZ COLOR COMPOSITE IMAGE ALSO INDICATES A WEAKLY-DEFINED LLC WITH ISOLATED DEEP CONVECTION DISPLACED NORTHWEST. A FORTUITOUS 020851Z SCATTEROMETER IMAGE REVEALS A DEFINED CIRCULATION WITH 10-15 KNOT WINDS OVER THE SOUTHER N SEMICIRCLE AND A SWATH OF 25 KNOT WINDS OVER THE NORTHERN SEMICIRCLE. DUE TO THE LACK OF ASCAT IMAGERY AND HIGH-RESOLUTION MICROWAVE IMAGERY, THERE IS LOW CONFIDENCE IN THE INITIAL POSITION. THE INITIAL INTENSITY IS ASSESSED AT 25 KNOTS BASED ON THE KNES DVORAK ESTIMATE AND THE SCATTEROMETER DATA. TC 09P IS LOCATED UNDER AN UPPER-LEVEL COL REGION WITH COMPLEX FLOW; DEEP CONVECTION IS FLARING UNDER THE DIVERGENT REGION OF THE COL WHILE THE LLC IS LOCATED UNDER THE CONVERGENT REGION. POLEWARD OUTFLOW IS RESTRICTED DUE TO THE PRESENCE OF AN UPPER-LEVEL LOW AND TROUGH TO THE SOUTH AND SOUTHEAST. ADDITIONALLY, THERE IS SIGNIFICANT DRY AIR PRESENT OVER THE SOUTHERN PERIPHERY OF THE SYSTEM WITH MID-LEVEL DRY AIR ENTRAINMENT. SEA SURFACE TEMPERATURES (28-29C) AND VERTICAL WIND SHEAR REMAIN CONDUCIVE.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN FAIR AGREEMENT WITH A 390KM SPREAD IN SOLUTIONS AT 72H AND REMAIN IN FAIR AGREEMENT THROUGH 120H. THE 020600Z ECMWF ENSEMBLE (EPS) STRIKE PROBABILITY GRAPHIC SUPPORTS THE JTWC FORECAST TRACK WITH MEDIUM CONFIDENCE. THE BULK OF THE DETERMINISTIC AND ENSEMBLE GUIDANCE TURNS THE SYSTEM SOUTHEASTWARD BETWEEN NEW CALEDONIA AND VANUATU. RELIABLE INTENSITY GUIDANCE SUPPORTS THE JTWC INTENSITY FORECAST WITH HWRF INDICATING A PEAK OF ABOUT 55 KTS NEAR 96H AND THE JTWC INTENSITY CONSENSUS (ICNW) SHOWING A PEAK OF 60 KTS NEAR 96H.

AN AREA OF CONVECTION (INVEST 90S) HAS PERSISTED NEAR 18.6S 80.4E, APPROXIMATELY 1510KM SOUTHEAST OF DIEGO GARCIA. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND A 020343Z MHS 89GHZ IMAGE SHOW A BROAD LOW LEVEL CIRCULATION (LLC) WITH PERSISTENT DEEP CONVECTION IN THE NORTHERN AND EASTERN SECTORS. A PARTIAL 020346Z ASCAT-B PASS REVEALS 20-25KT WINDS IN THE SOUTHERN PERIPHERY. ENVIRONMENTAL ANALYSIS INDICATES THAT THE INVEST IS IN A GENERALLY FAVORABLE AREA OF DEVELOPMENT DEFINED BY LOW (5-10KTS) VERTICAL WIND SHEAR, WARM (28-29C) SEA SURFACE TEMPERATURES, AND FAIR EQUATORWARD OUTFLOW. GLOBAL MODELS ARE IN AGREEMENT THAT INVEST 90S WILL SLOWLY DRIFT EQUATORWARD OVER THE NEXT 24-48 HOURS WITH GRADUAL INTENSIFICATION. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1002 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS MEDIUM.

GLOBAL MODELS ARE IN AGREEMENT THAT INVEST 90S WILL SLOWLY DRIFT EQUATORWARD OVER THE NEXT 24-48 HOURS WITH GRADUAL INTENSIFICATION.