Overview

• JMA confirmed Typhoon No. 18 formed east of the Philippines on Sept. 18 with central pressure near 1002 hPa and sustained winds of about 18 m/s.
• Forecasts project No. 18 will strengthen and move west to northwest with a possible approach to Okinawa’s Sakishima Islands around Sept. 22–23.
• Coastal seas around the Sakishima area are expected to build with swells beginning Sept. 20, and Yaeyama is already seeing clouds and periods of rain.
• Three typhoons—Nos. 17, 18 and 19—formed on Sept. 18, a clustering the JMA described as unusual for a single day.
• A separate low and front will drive very heavy rain and strong winds across northern Japan through Sept. 21, with up to 200 mm forecast in Hokkaido and 150 mm in Tohoku, and Fukuoka issued alerts for tornado risk, sudden downpours and lightning on Sept. 20.