An incoming trough of low pressure located not too far off the Northwest coast on Friday will swing through the region this weekend, allowing for some welcome relief following a very toasty stretch of weather this week. There is a catch to this cool down, however. While the Northwest will be able to enjoy more comfortable weather, the northern Plains will deal with intense heat. This won’t last long, through, as another warm-up returns early next week.
Following widespread, above-average temperatures on Friday, temperatures will take a nosedive on Saturday across the western two-thirds of Washington and Oregon. Highs will be up to 20 degrees below-normal, which means actual maximum temperatures will only be in the 60s and 70s.
East of the Cascade Mountains, heat will continue to crank on Saturday with temperatures nearly 20 degrees above-average. This means high temperatures will range from the 70s and 80s in the higher elevations, to the 90s and 100s in the valleys. Montana will act like a hot plate, with widespread temperatures soaring into the 100s, record-breaking in most climate-recording locations.
By Sunday, the cooler air will expand a bit more to the east, weakening in magnitude as the trough of low pressure lifts out to the north and east. High temperatures across most of Washington and Oregon, northern Idaho, and northwestern Montana will be up to 10 degrees above-average, translating to actual highs in the 70s and 80s.
To the south and east, it will be as much as 10 degrees above-average, with high temperatures in the 80s and 90s. The real heat on Sunday, however, will be found in the northern Plains. High temperatures in North Dakota will be up to 25 degrees above-average, meaning that the actual high temperatures will generally be in the 100s across both North and South Dakota.
These higher temperatures anomalies will also be found in the central Plains and the Midwest on Sunday as it will be around 5 degrees above-average, translating to temperatures into the 80s and 90s.
The core of this heat will shift into the upper Midwest by Monday, moderating as temperatures only go up 5 to 10 degrees. Meanwhile, back to the west, a brief cool down will pass through the interior Northwest. The heat will already begin to return to the Pacific Northwest following this, marking the start of another hot week.