Incoming storm to snap Utah's record warmth, bring snow back to the mountains

SALT LAKE CITY — Utah's run of record warmth and late summer-like temperatures is coming to an end, as an incoming storm is forecast to bring below-normal temperatures and mountain snow.

The National Weather Service issued its first winter storm watch for the season on Tuesday. It advises that snow accumulations of up to 18 to 24 inches are expected in parts of the Wasatch and West Uinta mountain ranges.

However, most mountain ranges will receive strong snow totals, while valleys across the state will receive rain, as well.

"It's going to feel a lot more fall-like around here," said KSL meteorologist Matt Johnson.

Storm timing and accumulations

Johnson explains that the first large storm of the season is arriving in Utah from the Pacific Northwest, as the latest high-pressure system set up over the state — which is keeping Utah warm and dry — moves out.

Windy conditions are forecast for Wednesday ahead of a cold front that is expected to reach Utah on Thursday morning, bringing precipitation with it. Johnson said it will likely sweep over the Wasatch Front by late morning, but he said some models project it could arrive closer to noon.

"It's going to be a one-two punch, with the first punch being kind of on the weaker side," he said. "That will have light valley rain and mountain snow above 9,000 feet."

A stronger cold front is forecast to arrive between late Thursday and early Friday, causing temperatures to plummet further while bringing heavier precipitation. Snow levels may drop to as low as 5,000 feet.

Everything is expected to clear out by the start of the weekend but not before impacting most of the state.

The weather service's storm watch says 10 to 18 inches of snow are forecast for the Wasatch Mountains south of I-80, while the Upper Cottonwood Canyons could receive as much as 2 feet of snow by Friday night. The West Uintas are forecast to receive 12 to 24 inches.

Other mountain ranges are forecast to receive slightly lower snow totals. Johnson said 6 inches of snow or more are possible for areas 7,500 feet or higher. Ranges above 9,000 feet are most likely to receive at least a foot of snow.

KSL Weather models indicate that the storm could produce as much as an inch of precipitation along the Wasatch Front by Friday evening and possibly over an inch across parts of central and eastern Utah. Johnson said some models indicate that valley communities could receive snowflakes, but he doesn't believe there will be much accumulation if that happens.

That's important because soil moisture levels — a key statistic for snowmelt efficiency in spring — have started to dry up again. The Natural Resources Conservation Service reported that soil saturation within the Uinta Basin, Western Utah and St. George regions had fallen to the bottom 10th percentile by the end of September.

"To flip the switch is really good news," Johnson said.

Cooling things down

The forecast starkly contrasts what the past few weeks have been like in Utah. For example, Salt Lake City is forecast to surpass 80 degrees through Wednesday, potentially extending the number of 80-degree days this month to 15 — five more than the previous record set in 1996.

Utah's capital also experienced its first recorded 90-degree October day on Oct. 4, along with four other daily records tied or set so far this month. With the string of record warmth, it's not a surprise Salt Lake City's average temperature for the month is on pace to end up at 70.8 degrees, over 10 degrees above the record set in 2015.

The incoming storm will at least help bring those numbers closer to normal. Freezing conditions are also expected in most places outside of the Wasatch Front and lower Washington County areas, according to the National Weather Service.

High temperatures along the Wasatch Front and northern Utah are forecast to drop from the upper 70s and low 80s on Wednesday to the low-to-mid 60s on Thursday; they may only top out in the low 50s on Friday, remaining in the 50s and 60s over the weekend. Overnight lows are forecast to drop into the 30s and 40s during this time, possibly even into the 20s in northern Utah communities.

High temperatures in St. George — which has also been abnormally warm this month — are forecast to drop from the low 80s on Thursday to the low 60s on Friday, remaining in the 60s over the weekend. Overnight lows will drop into the 40s by the weekend.

More to come?

The incoming storm may be the first of a few storms over the next few weeks. Multiple long-range models list most of Utah as having a higher probability of above-normal precipitation to close out the month, as more fall-like conditions return to the state.

It indicates that there might be more intermittent storms over the next few weeks, Johnson explains.

"That's good news because we definitely need to recharge the soil moisture right now before we put down that heavier snowpack," he said. "It's a promising sign."

Full seven-day forecasts for areas across Utah can be found online, at the KSL Weather Center.

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