I'm a professor at U Michigan and lead a course on climate change problem solving. These articles often come from and contribute to the course.
By: Dr. Ricky Rood , 6:49 PM GMT on July 13, 2014
Monday It Will be 80 degrees in Yellowknife
The forecast for Monday in Yellowknife in the Northwest Territories is for a high temperature of about 80 F. Pretty nice. Sunday it’s predicted to be 80 in Inuvik, here’s a link to the Inuvik Weblog: Saving lives above the Arctic Circle!
Of course the more important news is that “Temperatures could drop to sweatshirt weather by Tuesday, when an unseasonably cool pool of air is expected to reach the northern and northeastern U.S.” (In Washington Post, July 10 2014, many other press sources as well) This cool air will be coming with a nice animated name, The Polar Vortex. Actually that’s not quite true, it’ll be coming with a confused heritage. According to the Capital Weather Gang, “A memo was emailed from the NWS’ Central Region to local offices directing forecasters to cease use of the term [polar vortex] according to Chris Vaccaro, director of NWS public affairs.” Perhaps it will come with “Cool Temps but “no” Polar Vortex.”
It’s all too complicated for me. I’m going to stay in the easy west, go someplace like Inuvik (at end of Dempster Highway) where it will be nice and warm. It would be easier to get to Boise, Idaho where today’s (Saturday, July 12, 2014) high was 105 F, tomorrow 102 and Monday 103. Lytton, British Columbia is likely to be over 100 F. These temperatures, about 20 F above normal, must be a typical excursion, because, well, there’s no weather feature with an animated name.
Now it’s going to be pretty nice in Yellowknife, temperature wise, but they are having some trouble with air quality due to the forest fires. They aren’t helped by the nice weather, according to Judy McLinton, a spokeswoman for the Department of Environment and Natural Resources (Canada), who says, “It’s going to start heating up again and heat up during the weekend. And it’s going to be hot again even all the way to Inuvik and the Sahtu.” So far, however, the fire season has not been as bad as last year.
The polar vortex was pretty neat last winter. Even I wrote a whole series of blogs that talked about the polar vortex. I was trying to explain the vortex prior to it becoming a media event after cold air, uninteresting out west, moved to the east. Had I only been smart enough to call it “the polar vortex” in that blog. Let’s see, the polar vortex ended up in WUWT and the The Cato Institute as they attacked John Holdren’s Video on the Polar Vortex. Therefore, as a solidly political term, it’s a good idea to bring it back.
Enough. I am not secure in my satire. My tutorials and summaries on hot and cold, the Arctic oscillation and isolated polar air are linked at the bottom. I will, however, repeat a figure I used in the blog I posted on December 8, 2013.
Here is a figure from the European Center for Medium-Range Weather Forecasts (ECMWF), that I have marked up a bit. The colors are the temperatures at the 850 hecto-Pascal surface, which is about 1.5 kilometers above the surface. The 850 hecto-Pascal temperatures are a good indicator of where it is hot and cold at the surface.
Figure 1: This figure is from the point of view of someone looking down from above at the North Pole (NP). The contour lines on the figure are the height of the 500 hecto-Pascal surface, which is between 5 and 6 kilometers above the surface of the Earth. The colors are the temperatures at the 850 hecto-Pascal surface, which is about 1.5 kilometers above the surface. The 850 hecto-Pascal temperatures are a good indicator of where it is hot and cold at the surface. For completeness with my example, the big, black dashed line is the jet stream of air flowing around the pole. Figure from the European Center for Medium-Range Weather Forecasts (ECMWF)
Back in December, I drew a blue arrow showing that the cold air at the pole had wobbled off of the pole and was pushed towards Colorado. To the west there was warm air, red arrow, pushing up towards Alaska. So while it had been cold in Colorado, it had been quite warm in much of Alaska. I used this as a real-world example off the hot and cold contrast that is characteristic of wobbles in the jet stream. These wobbles have warm air poleward, displacing the cooler air from the pole, pushing it south.
Here is a similar figure valid for July 14, 2014. There is a complete description of the figure here. The jet is far weaker in summer, less continuous than in the winter (bold, dashed arrows). In fact, it is difficult to define a single “polar vortex.” A blue arrow shows the cool air that is pushed towards the Great Lakes. To the west there is hot air, red arrow, pushing into western Canada. Being summer, it is far warmer at the pole than in winter. Still the Arctic is a place of cool air compared to the middle latitudes.
Figure 2: This figure is from the point of view of someone looking down from above at the North Pole (NP). The contour lines on the figure are the height of the 500 hecto-Pascal surface, which is between 5 and 6 kilometers above the surface of the Earth. The colors are the temperatures at the 850 hecto-Pascal surface, which is about 1.5 kilometers above the surface. The 850 hecto-Pascal temperatures are a good indicator of where it is hot and cold at the surface. For completeness, the big, black dashed line identifies the jet stream. Figure from the European Center for Medium-Range Weather Forecasts (ECMWF)
This is an unusual pattern for the summer time. There are several intrusions of warm air towards the pole, and there are centers of cooler air, I count 5 of them, distributed around the middle latitudes. The cool air, which will be centered on the Great Lakes, is displacing hot air, which is present over much of the U.S. The predicted high in Dallas, Texas on Monday is 103 F. In fact, as we get towards Monday, the predicted high in Ann Arbor, Michigan is 78 F, which is not that cool. (Medium and long-range weather forecasts are less reliable in summer than winter.)
Is the weather story here, really how cool it is?
Is there purpose to this entry? Doing a news search of “polar vortex,” there is an indelible relic of an uncharacteristic cold spell related to the return of the polar vortex. This is followed by even more links to there being a cold spell, but it’s not the polar vortex, or it is some diminished personification of the polar vortex. The original focus on the polar vortex as an explanation of the cold (in eastern North America) was, perhaps, a well-intentioned simplification. Perhaps it was meant to grab readers, watchers, listeners and web-site traffic. As the polar vortex mutated through the media, it was recognized early as naïve, mocked by comedians, dismissed as scientifically imprecise and politicized. It then becomes a trigger, that supports the doubt that is the goal of the political argument to disrupt climate-change and energy policy. This is a case when the pursuit of simple metaphors and snappy descriptions of complex events fuels the rhetoric. It is a fundamentally flawed tactic of communication and a fundamentally robust way to capture attention and fuel disruption. We must do better.
Previous entries on hot and cold:
Cold and Snowy and Warm and Wet
Previous entries on Arctic Oscillation:
Climate Change and the Arctic Oscillation 2
Climate Change and the Arctic Oscillation 1
Wobbles in the Barriers
Barriers in the Atmosphere
Definitions and Some Background
August Arctic Oscillation presentation
CPC Climate Glossary “The Arctic Oscillation is a pattern in which atmospheric pressure at polar and middle latitudes fluctuates between negative and positive phases.”
The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.
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