After one of the hottest summers on record the fall has kept cooking.
“Warm is the story,” said Environment and Climate Change meteorologist Kyle Fougere on Wednesday.
Red Deer had its eighth warmest September in 100 years. The average mean temperature was 12.7, nearly three degrees warmer than the normal mean of 9.9 C.
“In fact, every station for Alberta was in their top 10 warmest recorded, except for one, High Level,” said Fougere. “So, across the province, it was a very warm September.”
Only five days in September in Red Deer were cooler than normal and four temperature highs were set.
On Sept. 3, the high was 31.7 C, compared with the previous 1938 record of 30.6 C. Another record was set the following day, when the high was 30.6 C, topping the 2013 record of 29.8 C. Another record was set on Sept. 11, when it reached 29.3 C, narrowly edging out the 2017 record of 29.2 C. On Sept. 28, the record books had to be updated again when the temperature hit 28.4 C, knocking off a 113-year-old record — 28.3 C in 1909.
The prolonged heatwave followed a hotter-than-normal August.
It was the third hottest on record for Alberta, capped off in Red Deer on Aug. 31 by a record-tying high of 31.1 C, matching a record set in 1940. Across the province, 22 temperature records were set that day.
Precipitation — more specifically the lack of rain — was another one for the record books.
The Red Deer station rain gauge recorded no precipitation at all for the month. While that would be a record for the driest September on record, that record comes with an asterisk at this point.
Three other sites located within the Red Deer area did record precipitation: Divide Hills (between Red Deer and Pine Lake), Lacombe and Prentiss (east of Blackfalds) all recorded precipitation ranging from 2.7 mm to 5.4 mm.
“That (Red Deer) data is suspicious,” said Fougere. “They’re looking into that, it looks like it’s a suspicious amount and it could have been an issue with the sensor.”
Even if precipitation matched the 5.4 mm recorded in Divide Hills, it would be the fifth driest September in Red Deer on record. The 3.7 mm recorded at Prentiss would go into the books as the second driest ever and the 2.7 mm of rain in Lacombe would be a new record low.
October is expected to offer more of the same, at least for the next couple of weeks. A system is expected to roll through early next week, which is likely to bring some rain, and possibly snow at higher elevations, before returning to warmer-than-usual weather.
“For the first several weeks of October we’re expecting it to be above normal as well.”
Thursday’s high is expected to hit 17 C, followed by Friday and Saturday highs of 21 C. Easter Sunday could hit 22 C and Monday 20 C, with rain and high of only 7 C forecast for Tuesday.
Fougere said an unusually persistent high-pressure ridge is behind the lengthy balmy stretch.
“We had a ridge of high pressure over much of North America. We saw it form in late summer towards the end of July. There have been a couple of systems that moved through that broke down the ridge, but it quickly rebuilt.
“When you have a ridge of high pressure you have descending air with it and the descending air prevents cloud and precipitation from forming and the heat then builds underneath the ridge and you get sustained warmth.
“It’s unusual for it to persist for so long.”
The ridge of high pressure has also kept the jet stream farther north, keeping the storms at bay that often roll through central Alberta regularly during the hottest parts of the summer.
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