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A messy weather setup is expected across Southern Ontario on Friday, as a burst of heavy snow moves into the region later in the day. Strong winds combined with falling snow are expected to create areas of blowing snow and reduced visibility, particularly through the afternoon and early evening hours. This has prompted Environment Canada to issue a widespread blowing snow advisory across much of Southwestern Ontario.

When it comes to impacts on school transportation, however, the situation is less straightforward. The worst conditions are expected to develop after the school day is already underway, with the most hazardous travel lining up closer to the afternoon commute rather than the morning bus run.

There may be some light snow around during the morning hours, but at this point, it does not appear to be enough on its own to meet the threshold that typically leads to school bus cancellations. Because of this timing, school boards would need to be proactive and factor in rapidly deteriorating conditions later in the day, rather than what is occurring at decision time in the early morning.

Given the blowing snow advisory from Environment Canada and the potential for travel conditions to worsen quickly while buses are on the roads in the afternoon, we have gone with a 50 percent chance for school bus cancellations for regions covered by the Bluewater District School Board, the Avon Maitland District School Board, and Middlesex County under the Thames Valley District School Board. This is very much a borderline scenario and could genuinely go either way. If this system were arriving a few hours earlier, confidence in cancellations would be much higher.

A second tier of regions carries a slight chance, around 25 percent, for a snow day on Friday. This includes areas covered by the Greater Essex County District School Board, the Lambton Kent District School Board, Elgin and Oxford counties under the Thames Valley District School Board, Wellington and Dufferin counties within the Upper Grand District School Board, the Near North District School Board, and the Rainbow District School Board. These areas are more rural in nature and are likely to see snow begin during or just ahead of the afternoon bus run. While most of these regions are expected to operate normally, a few localized decisions to cancel buses cannot be ruled out.

Outside of these zones, probabilities drop off further. We have assigned a widespread low to very low chance across rural school boards around the Golden Horseshoe and extending into parts of Central and Eastern Ontario. In these areas, the bulk of the snow is expected to arrive closer to the dinner hour, which greatly reduces the likelihood of school boards cancelling buses earlier in the day.

That said, if Environment Canada expands blowing snow advisories farther east or begins highlighting particularly poor travel conditions during the afternoon commute, some of the more weather-sensitive school boards could opt to cancel buses as a precaution.

For the more urban school boards, including those across the Greater Toronto Area and the Ottawa region, we are not expecting any school bus cancellations on Friday. Conditions in these areas are not forecast to come anywhere near the threshold that typically prompts cancellations, and travel should remain manageable through the school day.

Disclaimer: Instant Weather has zero authority when it comes to bus and school closures.

It is completely up to the school boards, bus companies, local authorities, and parents to decide what is best for their children. This is our best guess based on our forecast.