Piper City Fire Department issued the following announcement on May 21.
Tornado watch in effect until midnight - be weather aware - have a plan of action
The national weather service has issued tornado watch 236 in
effect until midnight cdt tonight for the following areas
In Illinois this watch includes 6 counties
In Central Illinois
Livingston
In North Central Illinois
La Salle Lee Ogle
Winnebago
In Northeast |Illinois
Grundy
This includes the cities of Byron, Coal City, Dixon, Dwight,
Fairbury, La Salle, Marseilles, Mendota, Minooka, Morris,
Mount Morris, Oregon, Ottawa, Peru, Polo, Pontiac, Rochelle,
Rockford, and Streator.
Original source can be found here.