ReliefWeb

JTWC Summary: TROPICAL CYCLONE 01B (AMPHAN), LOCATED APPROXIMATELY 480 NM SOUTH-SOUTHWEST OF KOLKATA, INDIA, HAS TRACKED NORTH- NORTHEASTWARD AT 08 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY INDICATES THAT TC 01B HAS SIGNIFICANTLY WEAKENED OVER THE PAST SIX HOURS, IN RESPONSE TO AN EYEWALL REPLACEMENT CYCLE, WITH THE EYE ACTUALLY FILLING AND DISAPPEARING FROM INFRARED IMAGERY OVER THE PAST HOUR. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE 9 NM EYE EVIDENT IN GOES-IO SATELLITE, SUPPORTED BY FIRST INDICATIONS OF THE INNER EYE ON IMD RADAR DATA. THERE HAVE BEEN NO MICROWAVE PASSES SINCE A 1514Z AMSU-B 89 GHZ IMAGE WHICH SHOWED THAT THE INNER EYEWALL HAS BROKEN DOWN ON THE EASTERN SIDE AS WELL AS INDICATIONS OF THE SECONDARY EYEWALL FORMING, ALSO OPEN ON THE EASTERN SIDE. THE LAST GOOD HIGH RESOLUTION MICROWAVE WAS A 1211Z CORIOLIS 37 GHZ COLORIZED IMAGE WHICH SHOWED THE SECONDARY EYEWALL FORMING ABOUT 25 NM OUT FROM THE CENTER, LENDING HIGH CONFIDENCE TO THE ASSESSMENT OF ONGOING ERC.THE INITIAL INTENSITY OF 130 KNOTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON A 6.0/6.5 DVORAK ESTIMATE FROM PGTW, AND A 6.5 CURRENT INTENSITY ESTIMATE FROM DEMS AT 1200Z.THE ADVANCED DVORAK TECHNIQUE CURRENT INTENSITY REMAINS AT 7.1, BUT THE FINAL T-NUMBER WAS ALSO 6.5 AT 1800Z....