‘Roller-coaster’ jet stream brings sweltering heat to the Far North


If you went looking for the highest temperatures in Canada on Monday, you may have had to travel farther than you think.

Although most southern parts of the country were enjoying some warm summer weather, with Toronto even under an extreme heat advisory and humidex advisory, the hottest part of the country was apparently up in the Northwest Territories, where several long-standing temperature records were broken.

In Yellowknife, the mercury reached 31.1°C, beating the previous record of 29.4°C from 1955, but temperatures got even higher in Fort Providence, where it reached 32.1°C (beating 29.0°C from 2010), and 33.1°C in Fort Simpson (beating 30.6°C from 1970). For Yellowknife, that apparently also beats the all-time record June temperature, which before this was 30.3°C from June 23rd, 1990, and this wasn't just some one-day fluke. Temperatures in Northwest Territories have been pushing or exceeding 30°C all weekend.

[ Related: How weather, geography made Alberta prime target for flood ]

Given that temperatures in Yellowknife and the surrounding area are typically more like 20°C this time of year, it goes without saying that it being warmer there than it is in southern regions of the country is a little weird, but it's not the only weird thing going on with the weather right now.

The jet stream — the relatively thin 'ribbon' of exceptionally strong winds that flows through the upper atmosphere, and is the driving force for a lot of the big weather systems that we see crossing over North America (and other parts of the world, of course) — has been acting pretty strange lately too... over the past three years, apparently, and in more recent days it's been responsible for not only the extreme heat up north, but it also played a part in the devastating floods in Alberta.

At times the jet stream can be fairly 'quiet', just stretching across the country from west to east and slowly shifting back and forth from north to south, but at other times, it can dip far to the south, dragging cooler temperatures down to the southern United States, and loop far to the north, pulling balmy temperatures along with it. During 'quiet' times, weather systems can zip across the country in a matter of a day or two, but when it dips far south, it can lock weather systems into place for days at a time, just like what happened with the 'omega block' that caused so much rain to fall in Alberta.

"There's been a lot interest in the jet stream in the last two or three years," said Environment Canada climatologist Dave Phillips, according to The Canadian Press.

"What we're seeing now is more of the dipping and the diving, looking more like a roller coaster than a ribbon," he added in the interview. "When that happens, it tends to kind of slow down. It doesn't move as energetically as it did and so therefore the weather can back up."

Whether this is just random fluctuations or as a result of climate change is still 'up-in-the-air' at the moment, because climate is the record of long-term weather patterns and it takes longer than two or three years to determine that kind of thing. However, seeing strange patterns show up definitely warrants investigation, and climate scientists are seeing some interesting

"What we seem to be developing, and there are some papers that are discussing this, is that the jet stream seems to be locking into these patterns longer," James Byrne, a climatologist at the University of Lethbridge, told The Canadian Press.

Weather and climate are complicated, so Byrne believes that it's going to involve more than just this 'wobbly' jet stream, but according to the interview, he said that it could be "a potentially powerful way to explain how climatic changes show up as weather."

"There's controls on how the jet stream behaved historically," he said. "Weaken one set of those controls, we're going to get some changes on how the jet stream behaves. It's probably demonstrating it quite well now."

[ More Geekquinox: Rare tsunami may have hit U.S. East Coast in mid-June ]

This is an important part of climate research right now. Gone are the days of simply trying to see if the world is warming, and we're even moving beyond the days where scientists are limited to just trying to tell how much we're warming now and what the long-term warming trends will be over a global scale. Now, it's an exciting time when climate researchers are actually getting to the point where they make meaningful studies of how this warming can and does affect smaller scale weather patterns. What would make it even more exciting is if the news coming out of those studies wasn't so scary.

(Photo & video courtesy: Jeff McIntosh/Canadian Press, NASA/Goddard Space Flight Center)

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