B. TROPICAL DISTURBANCE SUMMARY:
(1) AN AREA OF CONVECTION HAS PERSISTED NEAR 13.3S 168.6E,
APPROXIMATELY 310 NM NORTH OF PORT VILA, VANUATU. RECENT ANIMATED
MULTISPECTRAL SATELLITE IMAGERY AND A 020058Z GCOM-W1 89GHZ IMAGE
INDICATE FLARING CONVECTION AROUND THE NORTHERN AND EASTERN
PERIPHERY OF A BROAD AND ELONGATED LOW LEVEL CIRCULATION
CENTER. THE UPPER-LEVEL ENVIRONMENT PROVES FAVORABLE WITH GOOD
OUTFLOW ALOFT, SUPPORTED BY RIDGING EXTENDING FROM THE EAST, LIGHT
(5 TO 10 KNOT) VERTICAL WIND SHEAR, AND SUPPORTIVE SEA SURFACE
TEMPERATURES AROUND 30 CELSIUS. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 10 TO 15 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1008 MB. DUE TO THE BROAD CIRCULATION AND RELATIVELY
DISORGANIZED CONVECTION, THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS LOW.
TROPICAL DISTURBANCE TD15F CENTRE [1004HPA] WAS ANALYSED NEAR 19.4S
176.9E AT 032100 UTC. TD15F SLOW MOVING. POSITION POOR BASED ON
HIMAWARI-8 IR IMAGERY WITH ANIMATION AND PERIPHERAL SURFACE
OBSERVATIONS. SST AROUND 29 DEGREES CELSIUS.
CONVECTION PERSISTANT PAST 24 HOURS. ORGRANISATION POOR. CYCLONIC
CIRCULATION CIRCULATION EXTENDS UPTO TO 500HPA. SYSTEM LIES UNDER AN
UPPER LEVEL RIDGE IN A LOW SHEARED ENVIRONMENT.
GLOBAL MODELS HAVE PICKED THE SYSTEM AND MOVE IT SOUTHEASTWARDS WITH
GRADUAL INTENSIFICATION.
POTENTIAL FOR THIS SYSTEM TO DEVELOP INTO A TROPICAL CYCLONE IN THE
NEXT 24 TO 48 HOURS IS MODERATE TO HIGH.
JTWC提升評級至Medium
B. TROPICAL DISTURBANCE SUMMARY:
(1) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 14.8S
170.3E, IS NOW LOCATED NEAR 18.6S 177.0E, APPROXIMATELY 58 NM SOUTH-
SOUTHWEST OF NADI, FIJI. RECENT ANIMATED INFRARED SATELLITE IMAGERY
DEPICTS A DEVELOPING LOW LEVEL CIRCULATION CENTER (LLCC) WITH
FLARING DEEP CONVECTION. THE 031455Z SSMI 85GHZ MICROWAVE PASS SHOWS
WEAK FORMATIVE BANDING WITH DEEP CONVECTION ALONG THE EASTERN
PERIPHERY. THE UPPER-LEVEL ENVIRONMENT IS CURRENTLY FAVORABLE WITH
GOOD DIVERGENCE AND LOW VERTICAL WIND SHEAR (VWS) VALUES (5 TO 10
KNOT) OVERHEAD. SEA SURFACE TEMPERATURES (SST) REMAIN FAVORABLE AT
APPROXIMATELY 28 TO 29 CELSIUS. GIVEN THE CURRENT FAVORABLE
CONDITIONS, THIS DISTURBANCE HAS A NARROW WINDOW FOR DEVELOPMENT
BEFORE ENCOUNTERING SHARPLY INCREASING VWS AND DECREASING SST AS IT
TRACKS SOUTHEASTWARD. GLOBAL MODELS SUGGEST THIS WINDOW OF
DEVELOPMENT IS OVER THE NEXT 24-30 HOURS. MAXIMUM SUSTAINED SURFACE
WINDS ARE ESTIMATED AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 1005 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS UPGRADED TO
MEDIUM.