Utah's Labor Day weekend expected to start hot, then cool dramatically

SALT LAKE CITY — Got big outdoor plans for the last summer holiday weekend? Be prepared for a weather roller-coaster ride, as Salt Lake Valley temperatures could change by 21 degrees between Saturday and Labor Day.

After a high temperature in the low 80s Thursday, it will warm to the high 80s Friday, according to the Salt Lake office of the National Weather Service.

Then, expect a sizzling high of 93 degrees Saturday under clear skies. High pressure is building to the east of Utah, causing the warming trend.

The first dip in temperatures comes Sunday, with a high of 87 under still sunny skies, as a Pacific storm system will push a dry cold front through the state through Monday.

No precipitation is predicted through the middle of next week, and mostly clear skies will prevail. However, temperatures that decline to a high of only 72 degrees Monday will feel more like fall than summer.

KSL meteorologist Dan Pope also predicts a high in the low 90s on Saturday, followed by the 20-degree decline by Monday.

"Winds will pick up later Sunday and Labor Day," he said, as part of that dry cold front.

Overnight lows in the Salt Lake area will be 64 Saturday night, followed by 54 on Sunday night and 53 degrees on Monday evening.

"Make your water skiing plans for Saturday-Sunday and your barbecue plans for Monday," Pope said.

Bear Lake users will enjoy daytime air temperatures in the mid-80s Saturday, but that will decline to 77 Sunday and a brisk 64 on Monday. Overnight in the Bear Lake Valley will be downright chilly, with Sunday evening's temperatures there bottoming out at 40 degrees, followed by only 35 degrees Monday evening.

Lake Powell will be less affected by this cold front. For example, Hall's Crossing will bask in 94 degree temperatures Saturday, followed by a slight dip to 91 on Monday.

Zion National Park will feature 91 degrees Saturday and 83 degrees on Labor Day.

Even St. George will be affected by this temperature decline, going from a high around 102 Saturday to only 90 degrees Labor Day.

Has Salt Lake baked in its last 100-degree day already?

"It's over," Pope said, noting that Sept. 8, 1979, has boasted the latest-ever recorded century temperature reading in Salt Lake. With that cold front coming, he foresees no chance of any more 100 readings in 2010.

Salt Lake should warm to 76 degrees by Tuesday and near 80 by Wednesday.

e-mail: lynn@desnews.com