This Day In Weather History is a daily podcast by Chris Mei from The Weather Network, featuring stories about people, communities and events and how weather impacted them.
According to National Oceanic and Atmospheric Administration (NOAA), over 7,000 daily record temperature highs were broken or tied across North America from March 1 through March 27, 2012. This was a part of the March 2012 North American heat wave that is said to be “the most extraordinary temperature anomaly in North American history.”
The cause of the unprecedented relentless heat started with a jet stream with an unusually high-pressure ridge over the Eastern United States and an abnormally strong and slow low-pressure trough through the West. This caused an intense southerly jet that transported the warm and humid air from the Gulf of Mexico northward.
Toronto, ON, during the heat wave.
The winter had also been extremely mild, which means it takes less thermal energy to heat the atmosphere.
So North American was hot. Two-thirds of the continent experienced this extreme heat and temperature records were broken.
On March 21, both Grand Rapids, Michigan, and Chicago, Illinois reached a high of 31°C. Chicago had a record eight days at or above 27°C. This blew past many records, as Chicago only experience this heat as early as April.
Southern Canada shattered significant temperature records as well, including an impressive 30°C in Nova Scotia on March 22.
Smog in Calendon, ON.
Within Canada, Ottawa, Toronto, and Winnipeg had most of the heat. Winnipeg broke a 74-year-old record when it hit 22°C, which is also about 20 degrees above seasonal.
This was also foreshadowing a scorching North American summer. On June 25, Denver, Colorado reached a high of 41°C, tying its all-time high. Kansas reached 45°C on the same day. The summer continued to break record-after-record.
To learn more about the March 2012 North American heat wave, listen to today's episode of "This Day In Weather History."
Thumbnail: Courtesy of NASA