Say goodbye to the 80s, for now.
I won't make any proclamations that this is the end to 80-degree weather, because the way this year has been going, I'd bet we would see it again. But I'm more of a short-term forecaster, not necessarily long-term.
I will take a stab at the long-term forecast though because there are a lot of signs pointing to a series of cool swings of weather through the end of September.
The first is coming this weekend, September 15 and 16. A strong cold front will move through Friday night and possibly spark an isolated shower or thunderstorm. Otherwise it will drop temperatures by nearly 20 degrees across the board! In fact, a hard freeze and frost will be likely across the Adirondacks and NEK of Vermont Sunday and Monday mornings (Sept.16/17).
We will moderate a little bit, temperatures will then rise to around 70 for highs Monday the 17th of September. This is right around average for the area. In particular the average high Monday for Burlington is 69. I'm projecting 73 that day, so slightly above. However the large-scale weather pattern will then shift again into a cooler position.
Next week, September 17-23, long-range models predict a long wave trough to sink across the continental United States. A long wave what? Trough. You've probably seen the eye-appealing weather maps that show the jet stream taking a big 'U' shape or 'n' shape. Let's talk about the 'U' shape because that's what I expect to have next week, which indicates a cold air intrusion from the north. There are several long-range weather models available too, and they're all on board with this solution. This would mean "at or below average" temperatures for a good chunk of states and provinces in North America, including here in our local area. A few days we may sneak above average, but at least for the next 10 days, 80s will be a thing of the past.
-Meteorologist Steve Glazier