ReliefWeb

[JTWC] Summary: TROPICAL CYCLONE 11P (WINSTON), LOCATED APPROXIMATELY 164 NM EAST-NORTHEAST OF SUVA, FIJI, HAS TRACKED WESTWARD AT 13 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY, CURRENT RADAR IMAGERY FROM LABASA, FIJI AND A 191815Z SSMIS 91 GHZ MICROWAVE IMAGE CONTINUE TO REVEAL A SYMMETRIC EYEWALL SURROUNDING A 15 NM EYE AND THE MAINTENANCE OF DEEP CONVECTION OVER THE PAST 6-HOURS, PROVIDING HIGH CONFIDENCE IN THE INITIAL POSITION. THE INITIAL INTENSITY IS ASSESSED AT 145 KNOTS BASED ON NALYSIS OF ALL AVAILABLE SUBJECTIVE AND OBJECTIVE DVORAK INTENSITY ESTIMATES. UPPER LEVELANALYSIS SHOWS THAT TC WINSTON REMAINS IN A FAVORABLE ENVIRONMENT WITH STRONG RADIAL OUTFLOW, LOW (10 TO 15 KNOTS) VERTICAL WIND SHEAR (VWS) AND VERY HIGH SEA SURFACE TEMPERATURES (SSTS) OVER 31 CELSIUS. TC 11P IS CURRENTLY TRACKING WESTWARD UNDER THE INFLUENCE OF A DEEP-LAYER SUB-TROPICAL RIDGE (STR) TO THE SOUTH. BY TAU 36, TC WINSTON WILL BEGIN SLOWING, BECOMING NEARLY QUASI-STATIONARY BEFORE TURNING MORE SHARPLY TOWARDS THE SOUTH AFTER TAU 48 IN RESPONSE TO WEAKENING OF THE STEERING RIDGE AND CONCURRENT DEVELOPMENT OF AN UPPER-LEVEL CUTOFF LOW TO THE SOUTHWEST. TC WINSTON IS FORECAST TO CONTINUE TO STRENGTHEN OVER THE NEXT 12 HOURS AS UPPER LEVEL CONDITIONS AND SSTS REMAIN EXTREMELY FAVORABLE, PEAKING AT 160 KNOTS JUST PRIOR TO MAKING LANDFALL ALONG THE EAST COAST OF THE NORTHERN FIJI ISLANDS. AFTER TAU 12, TC WINSTON WILL WEAKEN SOMEWHAT AFTER LANDFALL DUE TO LAND INTERACTION. ONCE OVER OPEN WATERS BY TAU 36, TC WINSTON WILL MAINTAIN INTENSITY AS A SIGNIFICANT TROPICAL CYCLONE, BEFORE BEGINNING A SLOW WEAKENING TREND AFTER TAU 96 AS IT TRACKS OVER COLDER SSTS AND ENCOUNTERS HIGHER VWS AS IT BECOMES EMBEDDED WITHIN THE TROUGH. DYNAMIC MODEL GUIDANCE CONTINUES TO CONSOLIDATE ON THE OVERALL SYNOPTIC STEERING PATTERN AND IS IN GOOD AGREEMENT THROUGH TAU 72, LEADING TO HIGH CONFIDENCE IN THE JTWC FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 191800Z IS 40 FEET. NEXT WARNINGS AT 200300Z, 200900Z, 201500Z AND 202100Z.