This summer's been atypical for a lot of reasons -- heavy rains, high humidity, followed by a two week stretch where temperatures have been running below average. Most aren't complaining about that last point after dealing with lots of humidity and rain for much of the summer (and as outlined, likely dealing with more of it in the coming days as the pattern sets itself up for more) but to show the magnitude of weirdness, I thought I'd illustrate a point of how summer "cool" in one spot is yielding excessive warmth elsewhere.
Our average high and low the past three days in Philadelphia are 81.7 and 67.3, both of which are below average for us in early August and more typical of the Labor Day timeframe. We've benefited from a trough that's been situated over Hudson's Bay and Eastern Canada to provide a west-northwest flow of drying air aloft, with high pressure aloft (the heat ridge) situated over Texas and Oklahoma.
To the west of that upper trough, a spike of upper ridging has pushed into the high Arctic, with a blocking pattern setting up for the Northwest Territories and Yukon for the past few days and continuing into this week. The result has been rather warm weather for them.
Inuvik, which is 60 miles from the Arctic Ocean and situated at 68 degrees latitude, has had an average temperature of 82 and 61 the past three days. Their average for early August is around 59 for a high, 40 for a low...which yields temperatures just above 20 degrees above average for them.
You might remember Inuvik was an Ice Road Trucker town (if you watch the show), along with Tuktoyaktuk to its north and closer to the Arctic Ocean than Inuvik to its south. Tuktoyaktuk got into the mid 70's yesterday.
This regime of sorts is expected to continue, although with the upper low over Hudson's Bay pivoting back to the west somewhat and allowing for us to get more moisture, humidity, and a bit more warmth while keeping parts of Northwest Canada under the influence of this high pressure ridge spike that blocks in place. The result is continued warmth relative to average for the Northwest Territories and the Yukon over the next several days.