Is it April or July? Southern Ontario wakes up to rare spring heat
Southern Ontario received a nice Saturday morning jolt as temperatures experienced a rare spring surge--jumping to values more typical of a mild start in July, not April.
A brief spell of summer-like warmth helped push the thermometer over 20°C in parts of southern Ontario on Saturday.
It was even warmer on Friday. A centre of low pressure moved into the Great Lakes to end the week, raising temperatures to July-like levels. The mercury hit 26.2°C in Windsor, 25.2°C in Point Pelee, 24.3°C in Harrow and 24.0°C in Sarnia, Ont., during the day Friday. Windsor's value was good enough to make it Canada's hottest temperature so far this year.
Toronto notched its warmest reading of the year on Saturday afternoon when the temperature there rose to 22.5°C.
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This setup also brought Friday nighttime thunderstorms. Some of the storms reached severe limits, with heavy rainfall, strong gusts and frequent lightning.
But that wasn't it for the warmth. Did you step outside this morning?
Rare spring heat in southern Ontario
Temperatures rose sharply across southwestern Ontario as a mild warm front lifted across the region. Through pre-dawn hours Saturday, temperatures hovered near 20°C for Windsor, London and Hamilton, Ont., while temperatures shot up across the Greater Toronto Area (GTA) to more than 18°C.
Pearson International Airport recorded a 5-degree temperature boost Friday overnight when the southwesterly winds kicked in.
Here’s a reality check. The average low temperatures for April 19 are:
Windsor: 5°C
Hamilton: 3°C
London: 3°C
Toronto: 4°C
Saturday morning's temperatures were more typical of a mild start in July, not April.
For reference, here are July’s average lows:
Windsor: 18°C
Hamilton: 16°C
London: 15°C
Toronto: 17°C
Cold front spoiler
The reasons for the summer-like heat are the highly amplified jet stream and upper-level winds. A potent ridge of high pressure situated in the southeastern U.S., with troughing farther west. A weak low was able to lift north towards cottage country, bringing in with it some incredibly mild air from the Ohio Valley.
Risk of thunderstorm activity on Saturday is highest across eastern Ontario, but instability is limited due to ample cloud cover over the region. More favourable conditions exist for thunderstorm activity across southeastern Quebec, where a storm or two may approach severe criteria.
However, don't get too accustomed to the warmth as it will soon disappear.
A sharp cold front will slide in from northwestern Ontario by Saturday afternoon, dropping temperatures. However, daytime highs will spike into the low 20s across the GTA and eastern Ontario ahead of the front's passage.
Expect big temperature drops as the cold air swoops in for the Lake Huron sores, dipping as much as 5°C to 8°C drop per hour in some cases.
Temperatures will fall to freezing by early Sunday morning, especially away from the warmer, urban heat islands.
The sun could make a brief appearance on Sunday, but cooler temperatures, bitter winds, and possible scattered showers won't help improve the weekend's rainy theme.
Stay with The Weather Network for more information and updates on your weather across Ontario.