February Set to Go Out Like a Lion as Southern Ontario Is Targeted by Another Winter Storm on Monday
/Updated forecast
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Forecaster: Brennen Perry
Published: Sunday, February 26, 2023
Déjà vu, anyone? After reviewing the latest model data on the upcoming system for Southern Ontario, it looks like the colder air will win over across much of the region. We have adjusted our forecast moving the heavy snow zone further south into Central and Eastern Ontario. The freezing rain risk now covers an almost identical area as last week's storm with the heaviest icing expected across Sarnia through London and into the Hamilton/Niagara region. For the rest of Southwestern Ontario and into the GTA, we are looking at a mixed bag of precipitation including brief freezing rain, ice pellets and snow.
The timeframe of this winter storm is fairly similar to our initial forecast with precipitation expected to start during the late morning hours in Deep Southwestern Ontario and spreading northward throughout the afternoon. It will likely begin as freezing rain in the Windsor/Chatham region before transitioning over to rain as temperatures rise above the freezing mark by the dinner hour. As mentioned, those in the Sarnia, London and Hamilton corridor will see more prolonged freezing rain during the afternoon and evening where the cold air is expected to hold on.
We are also looking at a big impact on the evening commute as heavy snow and ice pellets affect the Golden Horseshoe starting during the late afternoon and continuing through the evening. There is still some disagreement on the exact temperature in this area, especially closer to the shoreline of Lake Ontario which would dictate the main precipitation type. Current indications suggest it should start as some heavy wet snow before transitioning over to ice pellets and even some freezing rain. Later in the evening and overnight, there is the potential that temperatures climb above the freezing mark around the shoreline leading to a transition over to rain.
For Central and Eastern Ontario, snowfall will start during the early evening hours, continuing throughout the overnight and into Tuesday morning. Strong to damaging wind gusts may also accompany this system with gusts expected to reach 60-80km/h by late Monday and may even come close to 90km/h east of Lake Huron. This could lead to power outages in the areas that received heavy freezing rain earlier in the day and blowing snow for those further north.
Everything will come to an end by Tuesday afternoon as the system moves out of our region. Total snowfall accumulation across Central and Eastern Ontario is expected to range from 10 to 15cm with some localized pockets (especially in the Ottawa Valley) picking up to 20cm. The icing from this event isn't expected to come near what we saw last week, but up to 4-8mm of ice accretion is possible in the hardest-hit region. Those in between the snow and freezing rain including much of Southwestern Ontario into the GTA will see a bit of everything so the exact totals are difficult to predict depending on the exact temperature.
PREVIOUS fORECAST
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Forecaster: Brennen Perry
Published: Saturday, February 25, 2023
It has certainly been an active month across Southern Ontario regarding the weather as we’ve experienced almost all the seasons over the past few weeks. This includes temperatures on both extremes from wind chills in the -30s to spring-like temperatures well into the teens. It shouldn’t be a surprise that February is set to conclude with a bang across our region as yet another messy winter storm is on the horizon for Monday into Tuesday. Impacts will vary across the region from heavy snow in Central and Eastern Ontario to potentially several hours of freezing rain in the south.
There is still some uncertainty regarding the exact intensity and timing of this storm so it’s quite likely there are some changes to the forecast as we get closer to Monday. At this point, it appears precipitation will start during the late morning or early afternoon on Monday in Deep Southwestern Ontario. With temperatures expected to be just above the freezing mark in the Windsor/Chatham area, it should come down in the form of rain. Total rainfall accumulation throughout this event will range from 10-20mm.
As the precipitation spreads further north throughout the afternoon it will encounter some colder temperatures east of Lake Huron and into the Golden Horseshoe. As a result, a fairly expansive zone of freezing rain will develop and impact Sarnia, London, Goderich, K/W and Guelph along with parts of the GTA away from the shoreline throughout the afternoon and early evening. This could lead to icy road conditions just in time for the evening commute on Monday so plan to leave extra time to get to your destination and drive according to the conditions!
The forecast gets tricky for those in the GTA around the Lake Ontario shoreline and into the Niagara region as temperatures will be very close to the freezing mark. Brief freezing rain is possible before it slowly transitions over to rain although if this transition is slower then more icing is possible. The Niagara region will likely see minimal freezing rain as the temperature is expected to rise faster there compared to other areas.
While this system isn’t expected to be as significant as last week’s storm that brought heavy ice accretion from freezing rain, the timeframe will be very similar as we see the worst impacts primarily during the evening across Southwestern Ontario and the Golden Horseshoe. Freezing rain will begin to transition over to rain in Southwestern Ontario as the temperature slowly climbs above the freezing mark during the evening and early overnight.
Total ice accretion could range from 5-10mm in the hardest hit regions, but this should melt away fairly quickly unlikely last week which would limit the overall impact. It may still result in some localized power outages with a thin layer of ice developing on untreated surfaces including trees and power lines.
Further north across Central and Eastern Ontario, we are looking at mostly snowfall with ice pellets mixed in for regions south of Lake Simcoe. Snow will start during the late afternoon and continue throughout the evening and overnight. Total snowfall accumulation is expected to range from 6 to 16cm with the highest totals in the more northern parts of our region. Those in Northeastern Ontario including Elliot Lake, Sudbury and North Bay could see up to 20cm of snow. We expect to see the snow come to an end by the noon hour on Tuesday.
As mentioned, this is a preliminary forecast as there is some uncertainty on how long the cold temperatures will hold on which would affect the overall ice accretion. There is more confidence in the snowfall portion of this event so if we make any changes, it will likely be in Southwestern Ontario and the Golden Horseshoe once we get a better idea of how quickly the switchover will occur. Check back on Sunday for a more detailed forecast.
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