It’s been an active evening across extreme Southwestern Ontario. Severe storms produced torrential downpours, damaging winds, intense frequent lightning, and eerie skies. One storm chaser tracking the storms got more than he anticipated today.
What is a dancing storm? Good question. The Fujiwara effect “dancing storms” refers to the interaction between two cyclonic vortices. When two low-pressure systems near each other, they begin to orbit one another around a mid-point separating the two systems. The effect gets its nickname from the interaction of two systems appearing to “dance” around one another. Read more here.
WINDY DAY SATURDAY ALONG THE HAIDA GWAII ARCHIPELAGO
Southeasterly winds will pick-up along the channel separating the islands and the Mainland, Saturday. The most powerful wind & waves will remain off-shore. Still, gusty winds & rainfall along Vancouver Island and the Archipelago will lead to a lousy day. Wind gusts between 60-90km/h are likely.
WET ALONG THE COAST WITH SNOW IN THE MOUNTAINS
An unsettled couple of days across the Lower Mainland & Vancouver Island. 25-35mm of rainfall is expected across Vancouver & Victoria through Friday & Saturday. This will be a beneficial rainfall across the region, where its been an unusually-dry start to spring. Unfortunately, the rainfall isn’t expected to penetrate far enough into the interior to bring any relief to the dry conditions.
A more prolonged and significant rainfall is expected along Western sections of Vancouver Island. 40-70mm of rainfall is expected by the end of the day Saturday. The mountain peaks along the coast will see heavy snow – mixing or light accumulation is possible along sections of Highway 19.
Alberta Clippers are synonymous for bringing snowfall lee of the Canadian Rockies, during December and January. These typically moisture-starved systems are fast movers, ejecting quickly out of Alberta, through the Southern Prairies – towards the Great Lakes. Read more about Alberta Clippers here.
A clipper is expected to form in Northern Alberta Saturday evening. Normally, these systems are more of a nuisance, accompanied by low snowfall totals and quick forward motion. On the contrary, this weekends system will flourish. Thanks to clashing temperatures and abundant Pacific moisture.
Accumulations will vary greatly throughout the Prairies, bearing in mind the heaviest snow will fall along a narrow swath. Current guidance suggests close to 15cm across the northern extent of the darker shaded region (in our forecast map). Including, Northern & Central Alberta. The heaviest snow (~20cm) will fall across Extreme Southwest Manitoba and Southeast Saskatchewan. *Model guidance has increased snowfall totals further into Southwestern Manitoba, where Environment Canada has issued snowfall warnings. Several warnings now stretch across parts of Prairies.
There will be another swath of snow tracking down the Rockies, bringing 10-20cm. It looks like Calgary will be limited to less than 5cm through Friday. By Saturday, a steep contrast in temperature envelopes the Prairies. Calgary will see a high of 9c and sunshine. Whereas, Eastern Saskatchewan will still be below freezing.
STRONG WINDS & BLOWING SNOW
Winds pickup between the Grande Prairie – Whitecourt corridor early Saturday evening. Winds sustained at or over 30km/h, gusting 60-80km/h. Gusty winds will overspread much of Alberta and Southern Saskatchewan overnight Saturday into Sunday morning. The strongest wind gusts aren’t expected to coincide with the heaviest swath of snow. Still, freshly fallen snowfall, which is dry and light – will combine with gusty winds. Bringing local blowing and drifting snow. Stay tuned to weather advisories, or statements pertaining to any potential road closures.
Colder air is beginning it’s decent across Southern & Central Ontario. Gusty winds this evening gives-way to Lake Effect rainfall Thursday night through Friday. First ‘bout of the season serves as a reminder that winter is coming.
Inland sections surrounding Agawa Bay to Montreal River Harbour will see Lake Effect rainfall beginning this evening. A transition to mixing or large flakes of wet snow is anticipated during the early morning hours Friday. Location: East of Lake Superior.
Accumulating snow will develop in Lake Effect bands near Wawa Friday night through Saturday.
Lake effect rainbands will setup tonight southwest of Georgian Bay and East of Lake huron. Owen Sound to Barrie to Orillia will be in for a chilly wet reminder that winter is coming. With rainfall bands meandering through the area.
Fairweather waterspouts are possible late Friday over Lakes Erie and Ontario, given the cold air aloft.
Heavy showers & thunderstorms beginning this afternoon in Sudbury and Algoma District. Continuing through the overnight.
An area of low pressure will rapidly intensify as it tracks through Northern Ontario towards James Bay. A sharp cold front will trigger heavy rainfall and thunderstorms today and tonight across Northeastern Ontario.
The primary threat will be torrential rainfall leading to minor flooding. Additionally, small hail and locally strong winds are possible in stronger thunderstorms.
Rainfall totals in the range of 30-60mm is expected north of Manitoulin Island & East of Lake Superior.
Thunderstorm Outlook from Environment Canada
Monday will be a pleasant seasonal day, dominated by high pressure and brilliant sunshine – across Southern Ontario & Quebec.
Wet, humid and stormy conditions start the week, with a risk of thunderstorms. Find out when and where.
Cloud, spotty showers, steady rainfall and humidity will make a return to Southwestern Ontario as early as tonight, with a warm front pushing northwards. Overspreading, the rest of Southern Ontario and Extreme Southern Quebec by Tuesday Morning.
Concurrently, an area of low pressure will strengthen along the Manitoba/Ontario border as it tracks towards Hudson Bay. 15-30mm of rainfall is expected in Northwestern Ontario. With wet snow mixing in across far Northern sections.
2 WAVES OF PRECIPITATION
The first wave of precipitation will arrive overnight tonight into Tuesday morning across Southern Ontario, moving into Quebec by the morning – ending early afternoon. Some embedded heavy-downpours is expended in a swath from the shores of Lake Erie to Niagara. Elsewhere, expect light to moderate rainfall and predominantly cloudy, warm and humid conditions. Dry slot arrives in the late morning to afternoon.
We will be watching Southwestern Ontario closely Tuesday, as any clearing could further destabilize the atmosphere increasing the risk of evening thunderstorms ahead of the cold front.
SECOND WAVE; RISK OF ISOLATED SEVERE THUNDERSTORMS
Associated with a sharp cold front – along a developing strong area of low-pressure forecast to deepen as it tracks through Northeastern Ontario and Quebec.
Thunderstorms will develop ahead of a cold front Tuesday night, persisting into Wednesday morning from East of Georgian Bay through Southwest Ontario. Isolated severe storms are possible. Bringing isolated strong wind gusts and heavy downpours.
A risk of isolated severe thunderstorms develops for Extreme Eastern Ontario and Southeastern Quebec late Wednesday morning or early afternoon, ahead of a sharp cold front. The primary risk will be damaging winds and heavy downpours. Isolated supercell(s) cannot be ruled out in Southeastern Quebec, but the risk will largely depend on timing & clearing.
Gusty southwesterly winds of 40-60km/h will overspread the risk area Tuesday. Becoming northwesterly through Wednesday. The strongest wind gusts of 60-70km/h will remain draped across Central Quebec and Nova Scotia.