Dangerous freeze and potent snow squalls take aim at Ontario, risk of 30+ cm

Tuesday will be a day to remember across southern Ontario, as temperatures soared into record-setting warm territory, and rare February thunderstorms spanned the region well into the overnight hours. Conditions will change in quite the hurry however, with a strong cold front ushering in powerful winds, a major temperature drop, and a sudden freeze.

Drivers are being urged to plan ahead for this rapid change, with the sudden drop in temperatures likely icing over roads and surfaces into Wednesday night.

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The winds will also stir up potent lake-effect snow, with localized totals of 20-30+ cm possible for regions east and southeast of Lake Huron and Georgian Bay. Areas southeast of Lake Superior will also be impacted, as the 'super squall' spans 1000+ km deep into New York State. Blizzard-like conditions are likely, if the winds persist into Wednesday evening, which could result in near-zero visibilities and potential road closures.

Wednesday into Thursday: Temperatures drop by as much as 20°C

Although Wednesday starts with more mild temperatures and early morning thunderstorms, a quick blast of winter conditions will be a harsh reminder of the season it still is.

Much of central Ontario and the Greater Toronto Area (GTA) will be the first to see the drastic drop in temperatures on Wednesday afternoon, falling from the high single digits to temperatures below freezing within just a few hours. The major temperature plunge will impact eastern Ontario by the evening hours.

Eastern Ontario, cottage country and parts of the traditional snow belts, including Barrie, are under a flash freeze warning. Temperatures in these areas will fall so fast as the intense cold front passes through, that any standing water will freeze by the evening, causing black ice and very slippery conditions.

WATCH: What is a flash freeze, and why is it so dangerous?

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It is possible for a temperature drop of 10-15°C within a three to four-hour period Wednesday evening, and an additional drop of 20-25°C over an eight-hour period from Wednesday evening to early Thursday morning. Be aware of sudden icy surfaces, and adapt your travel plans accordingly.

Temperature swings like this certainly do not happen quietly. Gusty winds between 60-80 km/h are a widespread concern Wednesday evening, with bitter cold wind chill values sinking in, as well.

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Dangerous snow squalls with blizzard-like conditions through Thursday morning

The precipitation will quickly change over to bursts of snow, including potent snow squalls off of Lake Huron and Georgian Bay by late Wednesday through Thursday.

Travel will extremely difficult and dangerous within the snow squall, as 60+ km/h winds and snowfall rates near 3 cm/h will significantly reduce visibility.

A narrow band of intense winter weather will cause havoc on the roads Thursday morning for portions of Highway 6 and 10, the Barrie region, and sections of the 400 and 401 east of Toronto. Drivers are urged to consider postponing travel during this time.

By the time all is said and done, between 20-30+ cm of snow could hit the hardest hit areas through Thursday.

Mild weather returns after new all-time record warm February records set

This dramatic switch to winter will be sudden, but also brief. Another extended stretch of exceptionally warm weather will return by Friday across southern Ontario.

Temperatures will soar well above seasonal through this weekend and early next week, with high temperatures more typical of late April and even early May. For many areas, daytime highs will reach the mid to upper teens, with a few spots even hitting the 20°C mark early next week. Onshore flow will keep many lakeshore areas much cooler, and that will include the GTA at times.

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Windsor became the first place in Ontario this year to reach the 20°C mark on Tuesday afternoon! Temperatures reached 21.4°C in Windsor, beating the city's previous record February high of 20.4°C set in 2000.

Sarnia also broke its own record high for February on Tuesday, with temperatures climbing to 20.7°C -- beating out the previous record of 19.4°C, also set in 2000.

Thunderstorms were widespread in southern and central Ontario through the day and night on Tuesday, with rumbles of thunder and lightning, and even some hail, putting a rare spin on the late February day.

MUST WATCH: Hail, not snow, piles up in Ontario during rare February thunderstorm

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Stay with The Weather Network for all the latest on your forecast across Ontario.