Utah forecast: Early taste of fall to be short-lived

You can finally break out the sweaters for a couple days. Fall does not begin officially until Sunday, but the crisp autumn air is making an early, if short-lived, appearance.

After a warm day Tuesday, highs in northern Utah will sink to the high 60s and low 70s through Thursday, before returning to the low 80s by week's end, according to the National Weather Service in Salt Lake City.

In southern Utah, highs will not break the upper 80s Wednesday and Thursday. The Moab area will remain in the 80s through the week, but St. George residents can expect a return to the 90s by Friday.

While meteorologists expect clear skies statewide, visitors to Arches National Park should still be wary of flash floods on Wednesday, thanks to heavy overnight rainfall.

The weather service issued a flash flood watch for the Salt Wash area of the park from noon to late Wednesday night. Heavy rainfall overnight will allow the Salt Wash to run, increasing flash flooding concerns for the Delicate Arch and Wolfe Ranch parking areas, as well as the walking bridge to Delicate Arch, according to the flood watch.

The Utah Division of Air Quality predicted "green" conditions throughout the state. The Intermountain Allergy and Asthma website, meanwhile, rates sagebrush as "very high," ragweed at "high" and chenopods and mold at "moderate" levels Wednesday.

Salt Lake City's high temperature are forecasted to reach 68 degrees Wednesday and 69 degrees Thursday; Ogden can expect 68 and 69 degrees, respectively, as well; Provo 70 and 72; Logan 66 and 68; Wendover 68 and 67; Duchesne 71 and 67; Cedar City 76 and 74; St. George 89 both days; and Moab 87 and 81 degrees.

mmcfall@sltrib.com

Twitter: @mikeypanda