Even though this week just started, I want to go ahead and fast-forward to late week/this weekend into early next week. We’ll discuss this upcoming week in this week’s newsletter, so be sure to give that a read if you’re signed up! I should have that out by tonight.
A shortwave feature is going to move across western Canada later in the week and eventually begin to dig southeastward and swing across the Northern Plains by this weekend. An upper-level low pressure system will develop and move over or near the Hudson Bay region. In response, a longwave trough will develop over the central U.S., and an early season strong cold front will move through a large chunk of the U.S., associated with a surface low pressure system that will develop and swing across Canada.
What all of this means is that some areas, particularly the central-third of the United States, will get to experience an early taste of fall. Regions to experience below average temperatures first will be Montana, Wyoming and the eastern Rockies late this week, and as the cold front sweeps southeastward over the weekend, temperatures will fall across the Plains, including parts of the Southern Plains. These cooler temperatures will eventually move into the Great Lakes region, the Ohio Valley, Tennessee Valley, and even into a large area of the Mississippi Valley by early next week.
Although temperatures should eventually cool some near the East Coast regions early to mid next week, the potency of the air mass shouldn’t be as strong by the time it reaches those regions, especially towards the Southeast. However, the lower moistures levels and slightly lower temperatures should be noticeable, given how hot and humid it has been in many of those regions this summer (which will continue this week, by the way).
As far as specific temperatures, lows should run in the 40s and 50s across the Central and Northern Plains early in the weekend. Temperatures may even dip down into the 50s for even parts of Oklahoma for a night or two this weekend. Low temperatures across the Midwest, Great Lakes, and Ohio Valley will drop down into the 50s and even 40s in spots late weekend into early next week. Temperatures could definitely even get quite cool across the Tennessee Valley and extend southward into northern and central parts of Mississippi and northwestern parts of Alabama, with temperatures running from the 50s to lower 60s from north to south. By early to mid week, the temperatures will cool down across the western Northeast and extend down the Appalachian Mountains. As mentioned above, the air mass should be a bit more modified by the time it reaches the far East Coast and far Southeast regions, but there still should be some noticeable differences early to mid next week. It might not be quite as cool as some of you in those regions might want though!
For highs, temperatures will be in the 60s and 70s for a couple of days during the same timeframe as described in the paragraph above. Temperatures will be in the 80s in the more southern areas described but still noticeably cooler with lower humidity values. Closer to the coast and far Southeast, 80s/90s will be common until the front makes it through, and temperatures may stay in the 90s across far southeastern regions.
So, this will be a nice and brief (2 to 3 day) cool-down for many of you. It’s important to keep in mind that below to well-below temperatures in August is different than what it is during the winter months.
Below are the probabilities of having below/above average temperatures in 6 to 10 days from now! Like I said, it will cool off farther east in some of those red-shaded areas on the map early to mid next week.
On a side note, this type of setup actually mimics what I believe could occur early this winter. The coldest of air will spill into central parts of the U.S. and move eastward will time. By the time it reaches the East Coast and Southeast, the air mass will be a bit more modified. Of course, since I believe Southeast ridging will be an issue early on this winter, that will further enhance above average temperatures at times across the Southeast and even along East Coast regions into the Mid-Atlantic and parts of the Northeast until January/February. A good recent example of that is the 2013-14 winter. I talk about all of this in my early 2016-17 winter forecast in much more detail, so please give it a read if you haven’t already!