Multi-Day Snowstorm Possible Across Southern Ontario Between Wednesday and Friday; Up to 40cm of Snow Possible

It certainly has been a snowy start to 2022 across Southern Ontario as we saw the most impactful snowstorm in years a few weeks ago. Well, it appears that February will be continuing the snowy trend as a multi-day snowstorm will set up what is best described as a snow ‘conveyor belt’ between Wednesday and Thursday. The snowfall will predominantly come in two separate waves within those 3 days with the first round starting Wednesday morning and lasting through to Thursday morning. Then we will get a few hours of reprieve from the snow before a second wave hits late Thursday and into Friday morning.

Based on the two different waves, we will be forecasting this storm with two separate snowfall forecast maps. At this point, there is more confidence in the first wave as we’re closer and there’s less uncertainty in the track. The second wave is still 2-3 days away and models have diverged in two different tracks which would have significant implications on the totals we see across Southern Ontario. Between the two waves, it’s not out of the question that we see widespread accumulation ranging from 20-40cm by Friday or even more.

In terms of raw accumulation over the three days, this event may overperform the last major storm that we saw that delivered widespread totals between 40-60cm. However, there is a big difference to see this accumulation spread over 48-72 hours compared to contained within a 12-hour timeframe. The impacts shouldn’t be as severe, but they will certainly be more prolonged so several days of travel delays and school bus cancellations are likely. This could also change if the second wave has less of an impact on our area.

This storm is expected to begin late Tuesday evening with the initial bands of precipitation moving into the Bruce Peninsula and areas around Georgian Bay. It appears that a few hours of rain is possible and maybe some freezing rain as temperatures hover near or slightly above the freezing mark. However, this will quickly change as we head into the overnight and Wednesday morning with temperatures set to drop below the freezing mark. Heavy snow will be ongoing throughout the morning on Wednesday and will begin to spread to the southeast later in the day as more sustained and intense bands of snow move in from the southwest.

It should also be noted that there is the risk of some freezing rain and mixing for a few hours during the day on Wednesday before switching over to heavy snow. This is particularly a concern for the Niagara Region and in Eastern Ontario which could see more prolonged freezing rain before the switch over. The worst conditions with the first wave will be felt throughout the evening and overnight hours on Wednesday. Heavy snow combined with 30-50km/h wind gusts will lead to blowing snow and very poor driving conditions. Travel should be avoided during this time and perhaps save any travel until Friday after the second wave.

The snow will begin to lighten from northwest to southeast overnight Wednesday and early Thursday morning. Most areas will likely see a short break from the snow late Thursday morning to the afternoon before the second wave moves in. The exception is for areas along the Lake Erie shoreline and Eastern Ontario which will see the moisture streams associated with both waves merge so there be not much of a break here.

As for the snowfall totals from the first wave, we are looking at the highest totals throughout Southwestern Ontario where general accumulation will range from 20 to 30cm including Windsor, Sarnia, London, K/W and into the Hamilton region. A few localized totals above 30cm by Thursday morning can’t be ruled out.

Further to the northeast, we have an expansive 15-25cm zone that includes much of the GTA and into Central Ontario. There is a particular area east of Georgian Bay including the Muskoka-Parry Sound region that could experience some lake enhancement Wednesday morning which could push totals slightly above 25cm.

Eastern Ontario will avoid most of the snow from the first round with totals ranging from 5-15cm depending on the location with higher amounts further west. This is mostly because the snow starts later and will merge with the second round so this will be covered in our second forecast.

Now, while there is fairly good confidence in the forecasted totals from the first wave, it’s not 100% so we still may need to make adjustments. We will re-evaluate the latest data on Tuesday afternoon and update the first wave forecast by early evening if needed. Any changes should be minor so don’t expect any major shifts or significant changes in the forecasted totals.

We will now lightly touch on the second wave which is still in flux when it comes to all the different models. This map might look quite familiar as the track of the second wave is similar to the major blizzard we saw a few weeks ago. As we saw with the last storm, it really comes down to the exact track in how much snow we received and last time it tracked further to the west which affected more of Southern Ontario. Some models suggest this more western track while others have pulled it further southeast. This southeastern track could be significant enough that it could miss Southern Ontario entirely so keep in mind our forecast right now is very preliminary. We’ve split the event into two waves so we could focus on the wave we have more confidence in.

We are going with the track that has the most model agreement with the second wave. This track would bring a fairly intense band of snow stretching from Windsor through the Golden Horseshoe and into Eastern Ontario. The heaviest snow is expected late Thursday continuing overnight and into Friday morning. Hourly snowfall rates during the evening and just after midnight could be quite intense ranging from 2-6cm which like the last storm, will pile up quite fast but not as intense as we saw with the 10+cm hourly rates. The snowfall will start to wind down late Friday morning as the system moves out of our region. It looks like Eastern Ontario will be the last to see the snow taper off and should be out of it by the noon hour on Friday.

The current track would result in an additional 20-30cm (locally 30+cm) of snow for the Niagara/Hamilton region and into Extreme Southeastern Ontario. Further west, we are looking at between 15-25cm for Windsor/London through the GTA and into the Ottawa Valley. With this track, the gradient will be quite tight like with the last storm so expect the totals to drop off quite fast as you head to the northwest. Totals here will range from 5-15cm including Sarnia, K/W, Barrie and Bancroft. If the storm starts trending more to the southeast then this area may end up with barely any snow so it’s not set in stone at this point.

A more detailed forecast for the second wave will be issued on Wednesday once we get a better idea of the track. This includes more specific timing and accumulation. Right now the focus is on the first wave and then we will turn our focus to the second wave. Stay tuned for further updates.