21 days and counting, Kilo to rank among longest-lived tropical cyclones on recordTyphoon Kilo, already the longest-lived tropical cyclone on on Earth so far this year, is well on its way to ending among the longest-lived on record at the end of this week. Kilo formed from a cluster of thunderstorms way back on Aug. 20, as a tropical depression south of Hawaii. Since then the storm strengthened to a very strong hurricane, the westernmost in a trio of Category 4s, marking the first time three storms of that intensity spun simultaneously in the northeast Pacific Ocean since satellite records began in the 1960s.

Then on Sept. 1, Hurricane Kilo crossed west over the international dateline and became a typhoon. East of the international dateline, Pacific Ocean cyclones are managed by NOAA’s Central Pacific Hurricane Center, which calls tropical cyclones “hurricanes.” The western side is monitored by the Joint Typhoon Warning Center, where tropical cyclones are called “typhoons.” FULL REPORT