LONDON, ONT. -- After several days of sun and heat, rain is making a triumphant return to southwestern Ontario.

Environment Canada has issued a Special Weather Statement for London-Middlesex, Chatham-Kent, Elgin, Oxford and Norfolk County due possible heavy rains.

Counties east of Oxford and Norfolk are also included in the statement.

A rain system coming out of Ohio across Lake Erie could produce 20-40 mm in some areas.

London is forecasted to get anywhere from 15-25 mm.

According to the weather agency there is uncertainty as to which areas might see the highest amounts of rain and warnings may be issued throughout the day.

More rain along with thunderstorms is expected Friday before sunny skies return for the weekend.

However temperatures will be much lower with a high of 16 degrees expected on Saturday.