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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 warning for the season on Wednesday ahead of a storm that could potentially deliver up to 20 to 24 inches of snow in parts of the Wasatch and West Uinta mountain ranges. The agency also issued a series of new winter storm watches for other mountainous areas in the state.
Valley communities are expected to receive plenty of rain on Thursday and Friday, too.
"It's going to feel a lot more fall-like around here," said KSL meteorologist Matt Johnson.
Storm timing and accumulations
The first large storm of the season is arriving in Utah from the Pacific Northwest, but windy conditions that are forecast ahead of the storm could pose new fire danger.
A few small showers are also possible in the mountains on Wednesday, but the much larger system is forecast to arrive on Thursday. Updated models now suggest that it will produce showers across northern Utah and the Wasatch Front beginning in the early morning and possibly during the morning commute, Johnson said.
"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."
On-and-off showers will linger throughout the day across the state before a stronger cold front is forecast to arrive as early as Thursday night. The second front will cause temperatures to plummet further while bringing heavier precipitation. Snow levels may drop to as low as 5,000 feet.
NWS Projections
The National Weather Service's winter storm warnings and watches project that the incoming storm could deliver:
- 12 to 24 inches of snow within the West Uinta range by Friday evening.
- 10 to 18 inches of snow within the Wasatch Mountains south of I-80 by the end of Friday, while the Upper Cottonwood Canyons could receive closer to 20 inches.
- 6 to 12 inches of snow within the Wasatch Plateau/Book Cliffs by Friday evening.
- 8 to 16 of snow within the central and southern mountains by Saturday morning.
Lesser snow totals are projected for other mountain ranges in the state, per weather service models. A few inches of snow is possible in Wasatch Back communities like Park City.
Storms will linger into Friday morning before it begins to clear out later in the day for most of the state. Mountain roads and passes will likely be slick and motorists should drive carefully, the weather service warnings and watches state.
Johnson said some models indicate that valley communities could receive snowflakes, but he doesn't believe there will be much accumulation if that happens.
KSL Weather models are now less optimistic about the storm's precipitation potential, largely because the storm is now forecast to move through the state faster than originally expected. Still, Johnson said many Wasatch Front communities could receive over a half-inch of rain by Friday evening.
Models also indicate that the core of the system may impact parts of eastern, central and southern Utah, so those areas could receive higher totals.
The highest precipitation values are still forecast in the mountains, which is 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. Salt Lake City is forecast to surpass 80 degrees again on Wednesday, 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. 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 70.6 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 forecast in most places outside of the Wasatch Front and lower Washington County areas, according to the National Weather Service.
Ready for fall? Changes are finally on the way, with much cooler temperatures by the end of the week, which will brought in with valley rain and accumulating mountain snow. Freezing temperatures are expected by Friday and Saturday mornings. #utwx#wywxpic.twitter.com/VMX3yhlb4A
— NWS Salt Lake City (@NWSSaltLakeCity) October 14, 2024
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 upper 50s on Friday before rising back into the 60s over the weekend. Overnight lows will drop into the 40s during that time.
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.
