Updated: The next 2 months of summer weather in Canada
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Wednesday, June 21, 2017, 10:01 AM - On this, the first day of summer, we look at how will a developing El Niño impact summer weather patterns across Canada? All the details below in The Weather Network’s 2017 Summer Forecast, which covers the remainder of June, July, and August.
(Editor's note: This article was originally published on May 23, 2017 as part of The Weather Network's Summer Forecast launch. It has been updated to reflect.)
The Short Answer
Most people prefer a short and simple answer to their forecast questions. However, the pattern for the upcoming summer does not lend itself to a simple answer, as we expect a more changeable and active pattern across most of Canada.
Changeable patterns during the summer tend to reduce the threat for widespread or prolonged drought and as such our forecast has all of Canada with near normal or above normal rainfall for the summer.
Keep in mind, though, that summer precipitation is notorious for being highly variable over short distances and it is inevitable that localized areas will miss out the showers and thunderstorms that occur in surrounding areas. Also, it is normal to have periods of dry weather during the summer.
A changeable pattern also reduces the threat for extended periods of excessive heat. While temperatures across most of Canada will balance out to near or slightly above seasonal, cooler than seasonal temperatures are expected for parts of central Canada and northern Atlantic Canada.
SUMMER IS HERE: With El Niño helping shape global patterns what will Canadians expect from summer? Find out with The Weather Network’s 2017 Summer Forecast | FORECAST & MAPS HERE
That’s a quick overview of the nation, but here are more details for each region of the country.
A warm summer is expected across the province, but we do not expect persistent extreme heat comparable to what we saw during 2014 and 2015.
This region saw abundant rain and mountain snow through the spring season, so that will reduce the wildfire threat early in the season. However, near normal precipitation is expected during the season that is typically the driest of the year. Therefore, the wildfire threat will increase somewhat as the season progresses.
It should be noted, though, that much of the rainfall during summer comes from scattered showers and thunderstorms which are notorious for producing localized torrential downpours (which can produce flash flooding) with not a drop of rain just a few kilometres away.
BELOW: Deeper dive into the Western Canada forecast: Chief Meteorologist
We expect that the Prairies will see a temperature pattern that resembles last summer, with alternating periods of above and below seasonal temperatures which should come close to offsetting each other across most of Alberta and Saskatchewan. Alberta has the best chance of seeing temperatures that end up on the warm side of normal, while near to below seasonal temperatures are expected across Manitoba.
With an active weather pattern at times through the summer, we do not expect widespread or prolonged drought conditions, though inevitably there will be some areas that get missed and become rather dry at times. If the Jet Stream pattern develops as expected, then there will also be a higher potential for cold core funnels.
Ontario and Quebec
This summer is not expected to be as hot or as dry as last summer, but the humidity will be more of an issue. Much like this spring, we have the potential to alternate between extended periods of both above seasonal and below seasonal temperatures. Across northwestern Ontario we expect that cooler temperature will be more dominant while southern and eastern Ontario should balance out near normal. The best chance of seeing temperatures tip to the warm side of normal looks to be across the Eastern Townships and near Montreal.
BELOW: Deeper dive into the Eastern Canada forecast: Chief Meteorologist
With competing weather patterns seeking to take control of summer, we recognize that at least one of those periods of warm or cooler weather could overachieve in duration or intensity and shape how the summer is remembered.
Rainfall is expected to be near normal across the region with the potential for above normal rainfall across parts of the south. However, since summer rainfall is highly variable over short distances, there is always the potential for localized areas to be dry while nearby locations are very wet.
A changeable summer is expected across the region with extended periods of above seasonal and below seasonal weather. The southern Maritimes and possibly into southern Newfoundland have the best chance of seeing temperatures tip to the warm side of normal. Meanwhile, cooler than normal temperatures are expected to be more persistent across eastern Labrador and northern Newfoundland.
Near normal rainfall is expected this summer. However, there is the potential for a couple of systems to tap into subtropical or tropical moisture and bring above normal rainfall to parts of the region.
The Yukon Territory can look forward to a warmer than normal summer while much of the Northwest Territories will see near normal temperatures. Below normal temperatures are expected for southern Nunavut while above normal temperatures are forecast for most of Baffin Island.
Near normal rainfall is expected in most areas but we will be monitoring the wildfire threat, especially across the Yukon and Northwest Territories.