t02436

JTWC提升評級到Medium

B. TROPICAL DISTURBANCE SUMMARY:
      (1) THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 13.2S
156.9W, IS NOW LOCATED NEAR 15.5S 152.5W, APPROXIMATELY 70 NM
NORTHWEST OF BORA BORA. ANIMATED MULTISPECTRAL SATELLITE IMAGERY AND
A 281957Z AMSU 89 GHZ IMAGE DEPICT A CONSOLIDATING LOW-LEVEL
CIRCULATION CENTER (LLCC) WITH FLARING, DEEP CONVECTIVE BANDING
WRAPPING INTO THE SYSTEM. RECENT ASCAT DATA REVEAL 25 KNOT WINDS
AND ISOLATED 30 KNOT WINDS WITHIN CONVECTION ALONG THE EASTERN
PERIPHERY OF THE LLCC. UPPER-LEVEL ANALYSIS SHOWS A FAVORABLE
ENVIRONMENT WITH LOW (10 TO 15 KNOTS) VERTICAL WIND SHEAR AND
IMPROVING OUTFLOW. RECENT OBSERVATIONS FROM BORA BORA INDICATE A 4
MB DROP IN PRESSURE OVER THE PAST 12 HOURS WITH WIND SPEEDS RANGING
FROM 20 TO 25 KNOTS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED
AT 20 TO 25 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE
NEAR 1003 MB. BASED ON THE IMPROVING LOW LEVEL SIGNATURE AND
SUPPORTIVE UPPER-LEVEL ENVIRONMENT, THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS UPGRADED TO MEDIUM.