A reprieve from the very cold temperatures Friday night was very short lived with frigid air blasting back into southern Ontario Saturday.
Environment Canada issued an extreme cold warning and a snow squall warning for Sarnia-Lambton late Saturday morning.
Forecasters say a sharp cold front will produce off lake snow squalls through Saturday into Sunday causing potentially hazardous driving conditions at times in snow and blowing snow.
Northwest winds gusting to 60 km/h will shift northerly before Sunday morning so both west and east Lambton are included in the warning.
The snow squalls will likely move into Middlesex and Lambton Counties beginning early Saturday evening, affecting places like London and Strathroy. They may eventually reach the Sarnia area later Saturday night or Sunday as winds become more northerly.
The snow squalls may significantly affect travel on all routes, including Highways 4, 7, 21, 401 and 402 with local snowfall amounts of 15 cm (6 in) quite likely in the strongest squalls. Travel plans should be changed accordingly.
The strong winds will produce dangerous wind chills around -30 C and therefore another exteme cold warning is in effect. We're advised to take precautions to guard against frost bite and hypothermia.
Sunday will be windy and bitterly cold with snow squalls and blowing snow diminishing in the afternoon.
Environment Canada says Sunday into Sunday night may be the coldest day and night of the season so far for many regions. A wind chill of -35 C is forecast for Sarnia-Lambton Sunday.
Temperatures Family Day Monday will slowly moderate after a frigid start to the day.