A life-threatening winter storm will impact Ontario, starting on Friday and lasting through the weekend.
While there are always comments from the public stating that weather people are always wrong or refuse to believe the forecast, this storm is of particular interest. This storm is strong. This storm has high agreement within the models. This storm is dangerous. The combination of the various hazards will result in extreme conditions.
Thursday
A strengthening low-pressure system will move across the United States on Wednesday and Thursday, nearing Ontario by Thursday evening. As the system moves close to Ontario, precipitation will start to fill in across Southern Ontario. This precipitation will be in the form of snow and/or rain. With either precipitation type, the precipitation will change over into rain through the late evening hours as the temperature climbs.
Hazards:
Wet surfaces from rain and/or brief snow in the evening hours
Friday
The rain will continue through the early morning hours before a cold front passes through the region. The timing of the cold front is not yet known, however, the majority of models suggest it will take place in the morning hours. This passage of the cold front will allow temperatures to plummet, causing a severe and rapid flash freeze. This will freeze wet surfaces in a fairly short period of time and may create hazardous travel conditions.
After the cold front passes through the region, the rain will change over into some intensity of snowfall. This may range from light to heavy at times throughout the afternoon hours. As the system progresses eastward, while strengthening, the winds on the western side of the system will strengthen and become NW or W, allowing for lake enhancement from Lake Huron. This may result in significant snowfall over 15cm. The exact snowfall totals on Friday are unknown at this point, however, amounts nearing a foot (30cm) may be possible in portions of Huron and Perth Counties (including surrounding lake regions such as Bruce County).
The strengthening system will allow the winds to strengthen throughout the afternoon. In the morning hours, the winds may gust up to 50km/h around the cold front, however, this will strengthen to between 70 and 100km/h by the evening hours. The exact wind speeds are unknown, however, 70km/h seems to be the minimal being portrayed by models. The maximum wind gusts are in question.
The combination of very strong, potentially damaging winds, alongside the lake-enhanced snowfall, will result in widespread blizzard conditions for areas east of Lake Huron by the evening hours with general blowing snow through the afternoon. Depending on the exact strength of the winds and the quantity of "wrap-around" snow after the cold front, these blizzard conditions or blizzard-like conditions may extend inland toward more populous areas (Middlesex, Oxford, Brant, Waterloo Reg., Wellington, etc.). If anyone has to travel further south towards Lake Erie, the winds will be strongest there, alongside some falling snow, so hazardous travel is likely.
The blizzard or blizzard-like conditions will almost certainly result in road closures Friday night. If the damaging winds result in power outages, it may be challenging for power crews to get to the outage region, let alone fix it. For this reason, power outages may be longer than usual.
Finally, the temperature will plummet after the cold front, resulting in negative double-digit temperatures by Friday night. With the strong winds, the wind chills may approach or surpass the -20s.
These combined hazards may result in impossible or nearly impossible travel. Getting stranded in this blizzard with extremely cold temperatures will be life-threatening to both yourself and first responders. There are no guarantees that first responders will be able to make it to you if you get stranded in the middle of a closed road in a blizzard. All travelling for the holiday season should be complete by Friday evening.
Hazards:
Wet surfaces will rapidly freeze during a severe flash freeze
Rain will changeover to snowfall, resulting in poor travel conditions from snow-covered icy roads
Blowing snow through the afternoon, changing into blizzard conditions by evening
Extensive road closures are possible and likely
Strong to damaging winds may result in power outages; the combination of blizzard conditions and road closures may make it difficult for power to be restored. Longer than normal outages are possible.
Extreme cold
Unknowns:
The exact timing of the flash freeze (and cold front) is unknown
The snowfall totals on Friday (estimated to range between 15-30cm)
The peak wind speeds on Friday (estimated ~100km/h on shorelines, give or take)
Saturday
On Saturday, the blizzard will continue. The very strong winds will persist throughout the morning and afternoon hours on Saturday. In the afternoon, the winds will be weakening, but they are expected to remain above 50km/h for the entire duration of Saturday, well supportive of blizzard conditions.
The system snow will slowly come to an end as the system moves eastward, however, lingering lake-effect squalls will persist over portions of Huron and Perth County (and surrounding snow-belt regions). The lake effect will start to weaken into the evening hours, however, it will continue through Sunday for some regions.
The combination of the ongoing lake effect, fluffy overnight snow, and strong winds will still lead to widespread blizzard or blizzard-like conditions for much or all of Saturday.
Similar to Friday evening, extensive road closures are possible. Hazardous travel is expected. Non-essential travel should be postponed. Extreme cold into the -20s via wind chills will remain possible.
Hazards:
Blizzard or blizzard-like conditions
Extensive road closures are possible
Strong to damaging winds may result in power outages; the combination of blizzard conditions and road closures may make it difficult for power to be restored. Longer than normal outages are possible.
Extreme cold
Unknowns:
The snowfall totals on Saturday (estimated 15cm+)
The peak wind speeds on Saturday (estimated ~80km/h, give or take)
Sunday
On Sunday, the lingering lake-effect snow will continue to weaken. The winds will continue to weaken as well, potentially reaching near or below 40km/h. The blizzard conditions will likely also come to an end, however, widespread blowing snow will remain a possibility on Sunday and into Monday, however, it won't be so persistent as Friday or Saturday. Travel isn't advised, however, it will likely be "doable" to some extent.
Extreme cold into the -20s via wind chills will remain possible.
Hazards:
Blowing snow
Road closures are possible
Extreme cold
Unknowns:
The snowfall totals on Sunday (estimated to range between <15cm)
The peak wind speeds on Sunday (estimated ~50km/h, give or take)
Summary
This is a serious storm. This is a dangerous storm. This is not a storm to take lightly. Preparation for potentially multi-day power outages or a multi-day blizzard should be made by Thursday. Travel will be horrible Friday night and Saturday. Expect road closures.
We will be actively updating road closures on our website here: https://www.weatherwatcher.space/road-closures
If you are looking for road closures in Huron and Perth County, we recommend joining this page: https://www.facebook.com/groups/HuronPerthWeatherWatch
Total snowfall amounts for this event will likely surpass 30cm, potentially nearing 50cm+ in some places.
An updated forecast with wind speeds, snowfall amounts, and timings will be posted in the coming days.
Environment Canada has created forecasts for Friday -> Saturday and Saturday -> Sunday. In both forecasts, they mention the risk of blizzard conditions near Lake Huron. They also mention the risk of upgrading their forecast to use the "extreme" threat level, something which has never been done before. This storm is big and should be treated as so.
