Japan Meteorological Agency | Radar and Nowcast …

Composite weather radar echoes and precipitation forecasts up to 60 minutes ahead are displayed in 1 km x 1 km resolution every 5 minutes, respectively. Any out-of-operation radars may cause radar echoes in affected areas to be weaker than they should be or not displayed at all. Precipitation Nowcasts provide precipitation intensity forecasts …

http://www.jma.go.jp/en/radnowc/