An Ontario divided sees snow in the north, thunderstorm risk in the south

Digital Writers
·4 min read
An Ontario divided sees snow in the north, thunderstorm risk in the south
An Ontario divided sees snow in the north, thunderstorm risk in the south

The calendar says spring, but Ontario is experiencing a true clash of two seasons this week. While the south is enjoying extremely warm and pleasant conditions this week, the north is on the verge of seeing a wintry whiplash from a potent storm.

The system is expected the blast the north Wednesday with 20-30 cm of snow, heavy snow and rain, as well as the possibility of prolonged freezing rain and ice pellets. Needless to say, travel is NOT recommended in areas north of Lake Superior. Special weather statements are in effect, warning of the wintry blast, which could leave some places digging out of 20-30 cm of snow by Thursday.

The south, on the other hand, may see some showers Wednesday afternoon, along with a risk of thunderstorms, however conditional the threat is. But if storms do develop along Lake Huron, from Kincardine down to Windsor, they may become strong and approach warning criteria. A more substantially potent system will push into southern Ontario Thursday night with heavier rain. More on the timing and impact through this week, below.

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The late spring-like weather that has hovered over southern Ontario the last few days will continue Wednesday, with daytime highs soaring to April and even early May-like values.

Despite temperatures remaining mild on Wednesday once again, a breeze from Lake Ontario will keep much of the Greater Toronto Area a few degrees cooler than inland regions in the south.

ONTempWed (Tuesday PPM)
ONTempWed (Tuesday PPM)

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However, the mild pattern will come with the first shot of unsettled weather Wednesday, thanks to a storm system tracking into northern Ontario. This will push a bit of moisture into the Great Lakes, but the day will be far from a washout.

"This will bring increasing cloud cover and the chance for a few rain showers on Wednesday," says Weather Network meteorologist Michael Carter. "Periods of sun will still be possible on Wednesday, however, and the day will still be quite warm for late March."

ONrain (Tuesday PMM)
ONrain (Tuesday PMM)

With mild temperatures providing a bit of instability in areas where the sun breaks out during the late afternoon and early evening, those passing showers could also be accompanied by a risk for thunderstorms -- mainly along Lake Huron, from Kincardine down towards London and Windsor.

The threat storms are rather conditional, depending on when the sun appears and if it can create enough daytime heating. But, some of the storms that do develop may be strong and approach severe warning criteria.

As well, winds will be quite gusty in parts of the south, strongest along the shores of lakes Erie and Huron, as well as Georgian Bay, possibly reaching the 40-60 km/h range Wednesday afternoon.


Thursday may offer the warmest temperatures in this extended taste of mild and above seasonal weather, with many locations nearing or reaching the 20-degree mark away from Lake Ontario.

ONTempThurs (Tuesday PM)
ONTempThurs (Tuesday PM)

"But these mild temperatures will be coming in advance of a stronger storm system, which will be tracking into the region late Thursday through Friday, which will end our dry period with a potential 20-30+ mm of rain, accompanied by gusty winds," Carter says.

The heavier rain will diminish to showers by Friday afternoon, with temperatures falling several degrees, though still remaining above seasonal for many.


While southern Ontario gets a glimpse of late spring-like weather, a potent winter-like storm threatens northern Ontario through Wednesday, prompting snowfall, freezing rain and rainfall warnings, as well as special weather statements for areas north of Lake Superior.

Snow will start overnight Tuesday and become heavy at times Wednesday morning. Some areas may see it mixed with ice pellets and/or freezing rain throughout the day, while others may see heavy rain.

ONsnow (Tuesday PMM)
ONsnow (Tuesday PMM)

In the freezing rain-warned areas, several hours of it are expected and significant ice buildup may occur before the precipitation transitions to snow overnight Wednesday or early Thursday morning.

Some areas from Geraldton to Moosonee could see as much as 20-30 cm fall through the day on Wednesday and into Thursday morning, when it tapers off.

By the weekend, much of the province will be back to an even playing field as cooler, near seasonal temperatures are expected. While next week may start off even slightly below seasonal, it still looks like the first half of April will tip to the milder side.

Stay tuned to The Weather Network for the latest forecast updates.