‘Ottawa’ Severe Thunderstorm Watch Issued for Ottawa Region
Get ready for thunder. Maybe.
Environment Canada issued a severe thunderstorm watch for the Ottawa region Wednesday afternoon. A severe heat warning was also issued.
“Conditions are favourable for the development of severe thunderstorms that may be capable of producing strong wind gusts and large hail,” Environment Canada wrote in a bulletin.
The weather agency warned of fast-moving wind blowing at speeds of up to 90 km/h, along with the chance of hail.
“Strong wind gusts can toss loose objects, damage weak buildings, break branches off trees and overturn large vehicles,” Environment Canada wrote. “Locally heavy rain is also possible. Remember, severe thunderstorms can produce tornadoes.”
However, thunderstorm activity does have one benefit: it could bring relief, at times, from the heat, said the weather agency.
Because hot dang, it’s hot outside.
“A hot and humid airmass will continue to affect the regions through Thursday,” Environment Canada said in their heat warning.
Overnight temperatures will be around 20 C and tomorrow the maximum temperature will be around 30 C.
“Maximum humidex values will approach 40 again Thursday,” the weather agency said.
But while Ottawans may be roasting, these temperatures are far from a record – or even an official heat wave.
And would you really want to swap it for the weather exactly five months ago?
That’s when Ottawa recorded a wind chill of -44.7 C, the coldest in a decade, according to Rolf Campbell who tweets as @YOW_Weather.
Campbell uses Environment Canada data going back to 1873 – although the humidex and wind chill index didn’t turn up until well into the next century.
He says there’s nothing odd about having a 33 C day by mid-summer except that we’ve already had four of them.
“That’s unusual,” Campbell said. “We usually have two or three in the whole year.”
This many hot days by mid-July happened in 10 of the last 140 years – the last time in 2012 – and is becoming more common with the urban heat island effect and climate change.
“This summer isn’t breaking any records – it’s warmer than average, it’s not crazy,” Campbell said.
It would have to be 32 C or hotter for at least three days to be an official heat wave but highs for the rest of the week are expected to stay in the high 20s with lows in the mid-to-high teens.
Ottawa weather extremes:
Hottest day of the past 10 years: 36.3 C, tie between Aug. 1, 2006 and July 21, 2011
Hottest day ever: 38.3 C on July 2, 1931
Highest humidex: 47 on Aug. 1, 2008
Longest Ottawa heatwave in the past 10 years: Four days, July 2010
Longest Ottawa heatwave: eight days, tie between July 1912 and August 1944
Coldest day in the past 10 years: -31 C on Jan. 16, 2009
Coldest day ever: -42.8 C on Feb. 13, 1913
Lowest wind chill index in the last 10 years: -44.7 C on Feb. 13, 2016
Lowest wind chill index ever: -47.8 C on Jan. 8, 1968