Weekend Outlook: Historical blizzard or just a weather advisory?

Sault Ste. Marie sits on the edge of two national weather agency boundaries. Typically, we see very little difference in the weather forecasts for the Sault between these two offices. However, the next 24 hours are different. Our American neighbours suggest a winter storm and blizzard conditions with a setup similar to last year at Christmas. Meanwhile, Canada's national weather agency is reluctant to issue much more than a weather advisory - not even a watch or warning. So what do I think?

What I see is a low-pressure centre moving into Michigan late Friday night that is one of the deepest (if not the deepest) in the last 30 years for January. There is agreement that winds will be sustained over 50km/h Saturday morning with gusts of 80-100km/h. Snow will fall, but there is a wide discrepancy between weather forecast models. Some suggest 10cm, and some suggest closer to 30cm. Regardless of how much, whatever does fall will be blowing and drifting, causing whiteouts on local highways.

It is clear that the worst of the storm will miss the Sault to the east. This means locations north of the city will see the least impact, and our neighbours down the line to the east will see a much stronger storm event. Adding to the complexities of this storm is that it could be followed by days of significant lake-effect snow. So, the areas that are spared the worst of the winter storm on Saturday could see much more snow by the end of the weekend and early next week.

Regardless of whose forecast is correct, everyone should plan for a high-impact event. The threat to local roads could result in some closures and treacherous driving conditions. The threat to local power lines from strong winds means that consideration should be given to a plan to stay warm during very cold weather conditions if the power goes out.

I have gas for my generator, my snow blower is ready, and my weekend plans to leave the house are on hold. Just in case. Now, here are the details of this weekend's forecast...

Skies clouded over Friday morning and will continue to build into the region during the afternoon, with temperatures near -6 °C and windchill values below -10. The winter storm moves in Friday evening, bringing blizzard conditions with blowing snow, reduced visibility, and windchill below -20. 5-10cm of snow is possible overnight, but it will be blowing and drifting with the strong winds.

The blizzard conditions continue into Saturday with blowing snow, daytime highs near -9°C and windchill values remaining below -20 thanks to strong north winds. Due to drifting and blowing snow, visibility will be near zero on local highways. Drifting snow will be difficult to measure, but 10-20cm is possible by the time it ends late tomorrow night, with higher amounts east towards St. Joseph Island and the North Channel. If the storm is missing the city, then by Sunday afternoon, we might see some breaks in the clouds and improved visibility.

Widespread snow ends on Sunday with afternoon temperatures near -8°C and windchill values near -20 again. Northwest winds arrive to bring a risk of snow squalls that could add even more snow to the city and locations north along Lake Superior. The risk of squalls continues into early next week to bring much more snow.