Official meteorological term for a weather advisory, less severe than a 警報 (warning). Used in phrases like 大雨注意報 (heavy rain advisory).
The Japan Meteorological Agency issued a heavy rain advisory.
Please stay away from rivers while the advisory is in effect.
A strong wind advisory was issued.
A heavy rain advisory is out, so it's better to avoid going outside.
The high wave advisory was lifted by evening.
tsunami advisory
photochemical smog advisory; smog alert