Beyond the immediate storm threat, cold air behind the system will usher in coldest air mass of the season, with temperatures struggling to reach low teens through midweek
The Sault Ste. Marie region remains under the grip of a significant winter storm on Monday morning, with dangerous and high-impact conditions continuing through the day. A rapidly deepening surface low-pressure system lifting through the Great Lakes has brought intense snowfall, combined with damaging winds gusting to 70km/h or higher. The system has created localized blizzard conditions across much of Northern Ontario, with near-zero visibility in falling and blowing snow.
Beyond the immediate storm threat, cold air behind the system will usher in the coldest air mass of the season, with temperatures struggling to reach the low teens through midweek.
Heavy snow will persist through Monday morning with rates approaching 10-15cm per hour. The most intense snowfall is expected through midday, with total accumulations of 20-25cm likely and localized amounts reaching 35cm or higher. Strong north to north-northwest winds sustained at 30-35km/h with gusts frequently exceeding 60-70km/h will combine with falling and freshly fallen snow to create localized blizzard conditions. The combination of strong winds and existing ice and snow on power lines and tree limbs creates a significant risk of power outages. Highway closures are likely, and travel is strongly discouraged through the afternoon. Conditions will gradually improve in the evening as the system pulls farther east, though gusty winds and blowing snow will persist into tonight. Daytime highs will be near -9°C, with lows overnight near -13°C.
Tuesday brings lingering impacts from today’s storm system with gusty northwest winds continuing through the day. While the heavy snow will have ended, periodic lake-driven snow showers will develop, particularly in the evening, as favourable northwest flow enhances moisture transport across Lake Superior. Additional accumulations will be limited to 1-3cm, but ongoing blowing and drifting snow will continue to create travel difficulties, especially on exposed roadways. Winds will gradually diminish from 30km/h to 20km/h, with gusts to 45-50km/h, though these will still be sufficient to maintain reduced visibility. Skies will remain mostly cloudy to overcast throughout the day. Temperatures will climb to -8°C, with wind chill values in the minus teens.
Wednesday will feature the coldest conditions of the week as persistent northwest winds maintain a notably frigid regime across Northern Ontario. Temperatures will struggle to climb out of the minus teens, even with any sunshine, with the high only reaching -11°C. Wind chill makes it feel considerably colder, potentially reaching -20°C during the dawn hours. Mostly cloudy skies will dominate as the active pattern continues, with periodic lake-effect snow showers possible, particularly in the afternoon and evening. Accumulations will be light at 0-2cm, but any snow combined with the bitter cold will create hazardous conditions.
Winds increase and remain out of the northwest on Thursday and Friday, bringing additional lake-effect snow. Another 10-20cm is likely, with some locations at risk for over 30cm. Totals for this work week could range from 40-75cm, possibly higher to the north of the city. Daytime highs climb slightly towards the end of the week and climb just above -10°C, but windchill values remain well into the minus teens.
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