textproduct: Salt Lake City

KEY MESSAGES, Issued 215 PM MDT Sat Oct 31 2026

- A lull in activity continues through early this evening ahead of an incoming system.

- A strong moisture push is expected late tonight with chances for rain increasing across the forecast area into tomorrow. Widespread light to moderate rainfall is expected tomorrow, with isolated instances of heavier rainfall rates possible across southwest Utah.

- Accumulating mountain snow is expected across all Utah mountains through Monday morning. Given high snow levels, 3-6" of snow is expected for most mountains. However, the Upper Cottonwoods and western Uintas may see localized accumulations 18-24" above 10000ft.

- Cool, dry, and stable conditions build in Tuesday following the passage of this system. Ensembles hint at an active period developing again later next week.

DISCUSSION, Issued 215 PM MDT Sat Oct 31 2026

Currently, a deepening mid-level trough is situated off the western U.S. coastline with broad southwesterly flow persisting across the Desert Southwest. Deeper moisture has been analyzed further south near the Baja Peninsula, southern CA, and southern AZ this afternoon with drier conditions further north, though some moisture currently exists across the forecast area with PWATs ranging from 0.6-0.8. Later this afternoon, a weak mid-level trough will traverse across UT providing modest ascent resulting in isolated to widely scattered showers and thunderstorms across the state, particularly across southwest UT. Storm motions ranging from 25-30kts from the southwest amidst lower PWATs generally preclude most flooding concerns today, though some localized nuisance flooding may be possible if storms track over already saturated locations given how wet it has been as of late.

Later this evening into tomorrow morning, the mid-level trough will deepen markedly and become negatively tilted as it interacts with a southern stream impulse further south. This will strengthen ascent across the forecast area with increasing PoPs areawide as a result. While this event is forecast to be a longer duration light to moderate stratiform rainfall event, rainfall totals raise concern given already saturated soils across much of the state. For most valley locations, 25th percentile amounts range from 0.75-1.25" with most mountains, southwest UT, and the Wasatch seeing 25th percentile amounts ranging from 1.50-2.00". For 75th percentile amounts, this increases notably for lower elevation locations with a range of 1.50- 2.00", and 2.50-3.00" for all specific aforementioned locations. While spread remains high, we must acknowledge that even the lower range of these rainfall amounts are rather high and could still result in areal flooding.

On Sunday night, a cold front will sweep across the area serving to put an end to most lower elevation precipitation. However, elevated moisture remains in place amidst northwest flow following the front, resulting in widespread mountain snowfall across the entire forecast area. For areas above 8000ft, around 3-6" of snowfall is expected from this system. Further north, primarily concerning the Cottonwoods and western Uintas above 10000ft, totals will range from 18-24" given northwest flow amidst ample moisture remaining in place.

On Monday, transient ridging builds in the wake of the departing system bringing cool, dry, and stable conditions to the forecast area. Another trough looks to impact the region mid-week bringing another stretch of unsettled weather, though spread remains high at this time making it difficult to iron out specific impacts.

HYDROLOGY, Issued 1012 PM MDT Fri Oct 30 2026

Through Sunday night, Issued 1012 PM MDT Fri Oct 30 2026... additional rainfall, locally heavy across southern Utah, will once again bring elevated potential for localized flash flooding and widespread rises to area waterways in southern and portions of central Utah. The most significant period of precipitation is expected on Sunday.

Earlier precipitation brought areas of flooding to portions of southwest Utah. However, coverage has decreased this evening. A relative downtick in heavy rain potential exists for Saturday, but the primary precipitation producer will be moving into the area Sunday. The broad upper trough off the Pac Coast is expected to phase with a strong short wave embedded within a strengthening southern tier jet. Anticipated set-up will allow a land falling atmospheric river (AR) to penetrate inland into southern/central Utah producing widespread moderate to locally heavy rainfall across the Arizona strip, Grand Staircase, and southern/central mountain regions, including National Parks and Recreation Areas within these areas. Rainfall amounts of 1-2.5" are likely with this, and given antecedent conditions, will efficiently runoff the landscape promoting widespread rises for all waterways, including streams, creeks, normally dry washes, slot canyons, and rivers across the region.

AVIATION

KSLC...Isolated showers will prevail through the evening, with rainfall becoming much more persistent after 07-08z. Light to moderate rainfall will likely continue through at least 00z Monday, with conditions worsening into MVFR first after 07-08z and further into low-end MVFR/high-end IFR after 16-18z. Southerly winds will largely prevail through the morning, but may become light and variable at times after 12z. Winds will transition to northwesterly between 20-22z as a cold front moves through.

REST OF UTAH AND SOUTHWEST WYOMING...Isolated showers will become much higher in coverage and more persistent statewide after 05-09z (across southern Utah first). Conditions will gradually worsen, becoming prevailing MVFR at most sites by morning, and even reaching IFR at many sites during the afternoon hours as this light to moderate rainfall continues.

SLC WATCHES/WARNINGS/ADVISORIES

UT...Winter Weather Advisory until 11 AM MDT Monday for UTZ111-112.

Flood Watch from 5 AM MDT Sunday through Sunday evening for UTZ120-121-123>125-127>131.

WY...None.