Active weather for first weekend of fall

SALT LAKE CITY (ABC4) — Happy first weekend of fall, Utah! This weekend will feature active skies in southern Utah, eventually reaching north to close it out.

High pressure in northern Utah is acting as a storm block, keeping the moisture-rich low pressure system at bay in the Desert Southwest. Southern Utah can expect scattered showers and thunderstorms sticking around both Saturday and Sunday with mostly cloudy skies and temperatures in the 70s for most and low 80s for St. George. A flash flood threat will persist in the south into Monday, especially in the state and national parks where slot canyons and low-lying areas can cause serious problems.

Northern Utah will be late to the party with mostly sunny skies in the forecast to kick off the weekend, although we can’t totally rule out a brief shower. Temperatures will be pleasant with highs in the low 80s for valleys and mid to upper 70s for mountain valleys. By Sunday the high pressure lifts, allowing moisture to surge into the north by Sunday afternoon. Isolated thunderstorms and mostly cloudy conditions will impact northern Utah to close out the weekend with temperatures cooling into the mid 70s for most and 60s to low 70s for higher terrain.

On Monday the system begins exiting to the east, but lingering moisture will spell a few more isolated showers and partly cloudy weather. However, another system is hot on the heels of the exiting system which will transport cool soggy air from the Pacific Northwest, bringing more activity for Tuesday. Tuesday will feature more isolated thunderstorms for northern valleys and mountains across the state, but we could see a couple showers make their way into southern valleys as well. 

By Wednesday lingering moisture brings a slight chance of a few more showers, but high pressure begins building again and should clear it out by the back half of the workweek. 

We’ll keep you updated on the latest developments in our 4Warn Weather forecast both on-air and online, we are Good4Utah!