textproduct: Salt Lake City

KEY MESSAGES

- A closed low continues to meander east across Utah providing continued chances for widespread light to moderate rainfall for areas primarily east of I-15. Mountain snowfall will continue across the Western Uintas (primarily northern slopes) and our central Utah mountains.

- A drying trend develops Thursday, persisting through the weekend.

- Freezing temperatures look to develop across locations such as eastern Box Elder county, Juab / Millard counties, Sanpete Valley, and higher elevation valley locations across southwest Utah Friday morning and potentially Saturday morning.

- High confidence continues to exist regarding another system impacting the forecast area around Tuesday next week. Guidance is now 50/50 on a southern split track versus the trough holding itself together, resulting in high uncertainty.

DISCUSSION

A closed mid-level low associated with a large mid- level trough continues to slowly meander east across southeastern UT. Ascent will gradually increase along its eastern periphery into the afternoon, bringing another round of low elevation rainfall and snowfall to the western Uintas and central UT mountains into tomorrow morning.

As the low continues east, a lobe of vorticity will dip south towards the AZ/CA border spinning up a large, albeit weak, trough across much of the southwest. This feature will meander across the area into the weekend, slowly retrogressing southwest and weakening with time as westerly flow develops across the Great Basin in its wake. This will yield mild conditions with a slight uptick in afternoon temperatures through the weekend with a dry pattern developing. Eventually, this trough will weaken enough to phase back into weak mean mid-level flow by Monday ahead of an incoming system.

Current model trends suggest a more east-northeast mid-level wind component across northern UT this evening into tomorrow morning, suggesting the canyon wind / localized downslope event will be more limited than anticipated. This is due to the mid-level low sliding somewhat further northeast over time than initially forecast in prior cycles. Regardless, typically windy spots (such as Ogden and Farmington canyons) may see gusts to 45mph in the immediate vicinities of each respective canyon mouth.

Across southwest UT, a gap wind event still appears likely to develop late this evening and persist into tomorrow morning as northwest flow amidst a tight pressure gradient continues to establish itself. While gusts will generally range from 30-40mph through much of the overnight period, gusts potentially reaching or exceeding 45mph (70% chance) look to develop around the 2-6AM timeframe primarily near the Beaver Dam Mountains and Blackrock Canyon. Winds are expected to diminish across the area before noon.

Another Pacific system looks to push into the western U.S. around Tuesday with favorable agreement among ensemble members (>80%). Compared to yesterday, however, ensembles are now split regarding two solutions which would greatly impact what we see across the forecast area. The first solution keeps the mid-level trough in tact, bringing widespread precipitation and mountain snow to UT and southwest WY. The mid-level trough remaining in tact is particularly important to this scenario as it will draw in notably colder air, resulting in favorable mountain snow conditions for much of the state. The latter solution is, unfortunately, quite similar to what we saw many systems do at the start of the 2025-2026 season where the system "cuts off" and forms a cutoff low to the south of the Sierra mountains. This will prevent more robust cold air advection further south, resulting in a warmer system favoring snowfall across higher elevation southern and central UT terrain. Additionally, this would result in weaker ascent further north with northern UT seeing weaker rain showers and little snow across the terrain. These early season systems are typically difficult to resolve at this timeframe, and this forecast will more than likely see major changes over the coming days.

AVIATION

KSLC...VFR conditions will continue at the KSLC terminal through the TAF period. Northwest winds will remain in place across the terminal into the overnight hours before switching to southeasterly flow around 9Z tomorrow. Low-level clouds with base around 5000 ft will continue throughout this afternoon until 0Z. There is still a chance of some showers this afternoon before those chances completely diminish this evening into the overnight hours.

REST OF UTAH AND SOUTHWEST WYOMING.... VFR conditions will continue at most sites throughout the TAF period. light northwesterly flow but also variable at times is expected across the majority of terminals through the overnight hours. Local pockets of IFR/LIFR conditions within can be expected fog and low ceiling at the KEVW terminal. Low-level clouds with base between 2000-5000 ft will continue throughout this afternoon until 0Z. There is still a chance of some showers this afternoon before those chances completely diminish this evening into the overnight hours across northern terminals.

FIRE WEATHER

Low pressure continues to meander across southeastern UT resulting in one more day of widespread rainfall and high elevation snowfall for areas east of I-15. High pressure builds in Thursday, bringing a drying and slight warming trend to all of Utah into and through the weekend. Mixing will remain limited given weak winds, inversion development, and October sun angle through the next few days.

SLC WATCHES/WARNINGS/ADVISORIES

UT...Winter Weather Advisory until 9 PM MDT this evening for UTZ112.

WY...None.