This is an archived article that was published on sltrib.com in 2016, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.

The first blush of autumn spreads through the hollows of the Wasatch Range, even as late-summer weather tightens its grip on the valleys and high deserts below peaks turning to gold and rust.

Low temperatures will dip into the low-40s in the northern mountains as this new work week unfolds, even as highs slip into the low- to mid-70s. That flirtation with fall will be less-pronounced the region's valleys, but overnight lows still will slip into the upper-60s, after daytime highs generally in the low - to mid-90s.

The Salt Lake and Tooele valleys will sweat under summer's late surge, seeing highs in the upper-90s Tuesday and Wednesday, up a few degrees from Monday's forecast. Thunderstorms expected late Wednesday will cool daytime temperatures into the low-90s.

It will take a few more weeks for encroaching autumn to find its way into much of southern Utah. Under clear, sunny skies, Highs in Utah's Dixie were forecast to flutter near triple digits on Tuesday, same as Monday; partly cloudy skies will shave a couple degrees off the sizzle on Wednesday.

The Utah Division of Air Quality's forecast through the midweek is brow-furrowing. Salt Lake, Utah and Davis were "yellow," or compromised for particulate pollution levels on Monday, with the rest of the state "green," or healthy. However, by Wednesday, the entire state — with the sole exception of Carbon County — was expected to be in the compromised air quality category.

The Intermountain Allergy & Asthma website reported that chenopods and sagebrush were "very high" on its pollen index as of Monday, with mold "high," and ragweed and grass at "moderate" levels.

For more extensive forecast information, visit The Salt Lake Tribune's weather page at: http//www.sltrib.com/weather/.

Twitter: @remims