But Matt Hebberd, co-owner of Rim Tours in Moab, has no doubt his clients will be enjoying the scenery outside Arches National Park as they pedal over the redrock through the weekend.

"We won't have any cancellations," he predicted.

Linda Cheng, a forecaster in the National Weather Service's Salt Lake City office, calls it "just a fall storm," thunderstorms blasting in from the Pacific Northwest and stirring up some heavy pockets of rain statewide. Accumulations of 1 inch are possible in some areas, especially in the south.

People should look out for flash floods in the slot canyons and mudslides in the scorched hillsides above Draper, where the Corner Canyon fire burned earlier this week, she added.

And Uinta Mountains campers - like anyone at elevations 8,000 feet or higher - might even see a dusting of snow when they wake on Labor Day morning.

In northern Utah, temperatures are expected to reach 100 degrees Fahrenheit on Saturday. They will drop nearly 20 degrees Sunday and tumble another 14 degrees Monday. The low Monday night is expected to get no higher than 39.

In southern Utah, Saturday's high of 100 will decline to an unseasonably cool 87 degrees Sunday and Monday. The low Monday night will be 55.

Like Cheng, Hebberd sees the wild weather as part of nature's usual fall routine in Utah.

"Usually," he said, "Labor Day is supreme." fahys@sltrib.com