First Wave of Multi-Day Snowstorm To Affect Southern Ontario With Widespread Accumulation Between 10-25cm Starting Wednesday

It’s increasingly likely that February will start off with not one but two heavy blasts of snow throughout Southern Ontario over the next 3 days. The first wave will begin early Wednesday morning and last into Thursday morning while the second wave will impact the region from Thursday afternoon to Friday morning. Between the two waves, we could be looking at widespread snowfall totals by Friday ranging from 20-40cm. Blowing snow will also be a concern throughout those timeframes so travel is strongly discouraged as road conditions will be quite poor.

As we mentioned in our preliminary forecast, there is more confidence in the snowfall totals associated with the first wave which will mainly target Southwestern and Central Ontario during the day on Wednesday. As we look towards the second wave, there is a lot of disagreement with the exact track making for highly variable snowfall totals across Southern Ontario.

The focus of this forecast will be on the first round where we have more confidence and we’ll make a separate forecast sometime on Wednesday for the second wave. We did include a very preliminary forecast for the second round HERE, but the latest data has trended further to the southeast so this will likely need to be significantly revised.

STORM TIMING

NOTE: For those that prefer daily snow totals, we’ve included what to expect by the end of Wednesday in the regional graphics above. Keep in mind that the timeframe for these graphics is different from the accumulation map for the first wave.

We will start to see the first bands of precipitation enter from the west sometime late Tuesday evening around midnight. For areas around Georgian Bay and the Bruce Peninsula, we may see a few hours of mixing with some freezing rain, but it will quickly switch over to snow by the early morning hours. For Southwestern Ontario, the rain and mixing will be more sustained as the warmer air holds on so the transition to snow won’t occur until later in the morning.

Moderate to heavy snowfall will be ongoing throughout Southwestern and Central Ontario during the afternoon and evening on Wednesday. The Golden Horseshoe and Eastern Ontario won’t start to feel the impacts of the first wave until later in the day towards the afternoon with a few hours of mixing also possible.

The snow associated with the first wave will continue overnight and into Thursday while slowly clearing from the northwest just after midnight. It should taper off for the most part by the late morning on Thursday giving us a break for a few hours before the second wave will move in during the afternoon.

This second wave is still unclear in the exact impact it will have on our region, but it’s a safe bet to say that the Niagara/Hamilton region and into Extreme Southeastern Ontario will see additional snow late Thursday into Friday. Accumulation will drop off quite fast to the northwest, but the track of the second wave will determine how far west the significant snowfall totals make it into the region. More details on Wednesday.

SNOWFALL ACCUMULATION

Based on the latest data, we’ve made some minor changes to our original forecast for the first wave. The main change is shrinking the 20-30cm zone which now only includes Southwestern Ontario (Windsor, Sarnia, London etc.). General snowfall totals here will likely end up somewhere around 25cm give or take a few centimetres with a few areas approaching 30cm. Now, it should be noted that rain and mixing here early Wednesday could inhibit accumulation on the ground for a few hours after the switch over which is hard to account for in the forecast.

Further east around the Golden Horseshoe, we’ve also reduced the snowfall totals here too as more mixing around the shoreline will likely reduce snowfall totals. The GTA can expect around 10-20cm with up to 25cm towards Hamilton and higher elevations of the Niagara Region by Thursday morning.

The forecast hasn’t changed much for Central Ontario where we are still expecting widespread accumulation between 15-25cm. Some of the data we’ve reviewed indicate that an area east of Georgian Bay including Muskoka into Bancroft could pick up closer to 25-30cm locally due to some lake enhancement.

Lower totals are expected for Eastern Ontario with around 5-15cm depending on your location. Although this is only for the first wave and Eastern Ontario will likely face the brunt of the second wave so they’ll catch up in snow totals late Thursday into Friday.

This will likely be our final forecast for the first wave unless there are any major changes in the model data this evening. We will pass along any last-minute updates if needed. Check back for a more detailed forecast on the second round sometime Wednesday once it becomes clearer on the impact it will have on Southern Ontario.