First Snowstorm of the Season Targeting Southern Ontario on Sunday With Up to 20cm of Snow Possible by Monday Morning
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Usually, by now most of Southern Ontario would’ve experienced a significant snowfall event as we head into the middle of November. That isn’t true this year though as aside from regions in the snowbelts, we haven’t really seen much snow which is a result of the fairly mild fall that we’ve had this year with many areas still experiencing double-digit temperatures even into November.
Unfortunately, all good things (that is if you don’t like snow) must come to an end and it’s going to be quite the jump from early fall-like weather to something we would see in early December beginning early Sunday. That shift in the weather is courtesy of a system that is expected to move into the region Sunday morning and lasting throughout the day and into Monday morning. For most areas, it will bring the season’s first significant snowfall including much of Southwestern, Central and Eastern Ontario and parts of the GTA that are away from the lakeshore. There is the potential for as much as 12-20cm of total snowfall accumulation by the time the storm moves out of the area on Monday morning.
STORM TIMING
TIP: You can click on the image to open it in a new tab and be able to zoom into the graphic.
TIP: You can click on the image to open it in a new tab and be able to zoom into the graphic.
With the first significant winter storm ahead of us for Southern Ontario, we thought this would be a good time to launch some new graphics we’ve been working on over the past few months. One of the most frequent questions we get is usually about timing for a specific location or region so we’ve broken down the province into 12 zones and outlined the precipitation timing hour by hour to help you better plan out your day. Obviously, it won’t be perfect as the forecast can change but hopefully, it’ll give you a rough idea of what to expect for your area - we tried our best to cover all the major population centres so if you can’t find your location just focus on the city on the graphic that is closest to you. Let us know what you think of the new graphic!
Back to the forecast, precipitation will begin to enter the region from south of Lake Erie beginning early Sunday morning around 7-8 am. The first areas to be affected will be the Windsor and Sarnia region starting with a rain/snow mix and transitioning to heavy snow later in the morning and into the afternoon. Snow will continue to spread to the northeast throughout the day on Sunday reaching the GTA and KW area by late morning. Those right near the lakeshore particularly around Lake Ontario and Erie will likely see rain or a mix of rain/snow due to temperatures being slightly warmer. The snow will intensify further during the afternoon as it spreads further north reaching Central and Eastern Ontario just after the noon hour. This is except for the Ottawa Valley into Renfrew which won’t see the first flakes until around 4-5 pm.
Precipitation will continue mostly in the form of moderate to heavy snowfall into the evening as we being to see it taper off in Extreme Southwestern Ontario and some rain mixing back in through the Hamilton/Niagra region. In Eastern Ontario, there is the threat of a few hours of freezing rain between 10 pm - 2 am including Kingston and Brockville (Ottawa may see an hour or two but it should remain mostly snow). The system will begin to exit our region early Monday morning with precipitation coming to an end just after midnight for most areas (Eastern Ontario will continue to see heavy snowfall into the mid-morning hours).
SNOWFALL TOTALS
TIP: You can click on the image to open it in a new tab and be able to zoom into the map.
TIP: You can click on the image to open it in a new tab and be able to zoom into the map.
Now onto the tricky part of the forecast which is the expected snowfall accumulation from this system. While we’re fairly confident in the timing and track of this system the problem is where the temperature will end up during the day on Sunday and into the evening. Most models seem to suggest that areas away from the lakeshore should stay below the freezing mark throughout most of the day which would be favourable for significant snowfall accumulation. This zone extends from the Quebec border through the Kawartha Lakes and into parts of Southwestern Ontario and the northern GTA. So areas like Renfrew, Ottawa, Peterborough, Newmarket, Guelph and Kitchener/Waterloo will likely see total accumulation between 12-20cm.
The accumulation will drop off the further to the northwest you go due to the majority of the moisture being focused on those east and south of Lake Simcoe. Areas such as Barrie, Orillia and Muskoka can expect as much as 5-10cm and even less through the Bruce Peninsula and Parry Sound/North Bay.
The tricky spot is along the shoreline of Lake Erie and Ontario and those out in Eastern Ontario along the international border where some models suggest that rain or even freezing rain could mix in at times. This would reduce the potential snowfall accumulation and melt any snow that has already accumulated. We have decided to put Hamilton, Toronto, Kingston and Brockville in the 2-6cm total snowfall accumulation zone but it could easily end up much higher should less rain mix in. It’s important to mention that this area has the potential to overachieve the forecast by a big margin should it remain all snow as the moisture is there (some models have as much as 20cm through the GTA even near the lakeshore but this is unlikely). Overall, the further inland you are, the greater the chance that you see over 10cm of snowfall accumulation.
We’ll continue to monitor the latest data and issue any updated forecasts if necessary.
The accumulation will drop off the further to the northwest you go due to the majority of the moisture being focused on those east and south of Lake Simcoe. Areas such as Barrie, Orillia and Muskoka can expect as much as 5-10cm and even less through the Bruce Peninsula and Parry Sound/North Bay.
The tricky spot is along the shoreline of Lake Erie and Ontario and those out in Eastern Ontario along the international border where some models suggest that rain or even freezing rain could mix in at times. This would reduce the potential snowfall accumulation and melt any snow that has already accumulated. We have decided to put Hamilton, Toronto, Kingston and Brockville in the 2-6cm total snowfall accumulation zone but it could easily end up much higher should less rain mix in. It’s important to mention that this area has the potential to overachieve the forecast by a big margin should it remain all snow as the moisture is there (some models have as much as 20cm through the GTA even near the lakeshore but this is unlikely). Overall, the further inland you are, the greater the chance that you see over 10cm of snowfall accumulation.
We’ll continue to monitor the latest data and issue any updated forecasts if necessary.
