Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
706 FXUS65 KSLC 022228 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 328 PM MST Tue Dec 2 2025 .SYNOPSIS...An active pattern will continue across the region through the weekend. An upper level low will bring the threat of snow to most locations tonight into Wednesday morning across northern and central Utah. After a break, another storm system will impact portions of northern and central Utah Friday into the weekend. && .DISCUSSION...An active pattern will continue to impact the region through at least this weekend. Early afternoon upper air and satellite analysis indicates deep northerly flow from Alaska into the Intermountain Region. An upper level low embedded in this flow is near Boise this afternoon and will shift south through the overnight hours. Showers continue across northern Utah, though dewpoint depressions are such that most precipitation is evaporating prior to reaching the ground. Two main scenarios can be expected across northern Utah this evening into the overnight hours. The first and most likely scenario (85% chance) is periodic snow showers will continue across northern and central Utah as the upper level low shifts southward through 09-12Z Wednesday. Given the showery nature of the precipitation, the most likely valley snow total range will be trace to 2 inches, up to 3 inches on benches especially for Tooele County. Scenario 2, while unlikely (15% chance), would be more impactful. In this scenario, forcing with the upper level low will combine with northerly flow over the Great Salt Lake to bring a period of moderate to heavy snow to eastern Tooele County and northwestern Salt Lake County...beginning around 6-8 PM and continuing through 3-5 AM. This scenario would bring heavier snow accumulations, around 4 to as much as 8 inches for the eastern Tooele Valley, Magna and the remainder of western Utah through about Taylorsville to West Jordan. For now, confidence in the higher impact scenario is below the threshold for any type of winter weather advisory, but those who have overnight travel and/or an early morning commute in the Tooele and western Salt Lake Valley areas should be prepared for the potential for winter driving conditions. In the wake of the upper level low, shortwave ridging will build across the area. As a strong jet max shifts around the northern side of a robust eastern Pacific ridge, synoptic scale forcing combined with mid-level warm air advection will shift into northern Utah late Thursday into early Friday. Precipitation will initially begin as snow across the northern valleys, but gradually increasing snow levels will slowly change any snow to all rain for most valley locations Friday afternoon into Friday evening. The heaviest precipitation with the first round is expected Friday evening into Saturday morning associated with the left exit region of the jet max. Another period of deeper forcing Saturday evening into Sunday will bring the potential for another round of precipitation. Current 25th to 75th percentile snow accumulations for the northern mountains range from 8 to 18 inches with locally up to 2 feet in the upper Cottonwoods. Valley snow totals would range from around trace to 2 inches valley floors, up to 4 inches benches...most of which would fall early in the event. Looking at the last four runs of the major ensemble systems, around 30% of the ensemble members represent an alternate scenario to the above description, with the best jet support remaining north and east of the region. This subset, while 15% of the members in earlier runs has an increased following with the 12Z runs (up to 30%). Whether this is represents an increasingly significant shift in the guidance remains to be seen...but total accumulations would be roughly 50% of the current forecast in this scenario (roughly 4 to 8 inches for the northern mountains). The vast majority of ensemble members build the eastern Pacific ridge eastward next week. Whether this is a dry pattern, or whether shortwave troughs embedded in northwesterly flow shift occasional cold fronts with associated precipitation across northern Utah will be the main question. Confidence is much higher that central and southern Utah will shift into a dry, more typical La Nina pattern. && .AVIATION...KSLC...CIGs are expected to drop and remain below 6000 feet around 23-00z as a cold storm brings snow showers to the terminal. Reductions to MVFR and brief IFR conditions are possible in the evening and overnight as a period of heavier precipitation is expected to accompany a frontal passage. Winds remain overall light through the TAF period, with a period of variability as showers approach the terminal, switching northerly by 00z and remaining north behind the frontal passage overnight and into tomorrow. .REST OF UTAH AND SOUTHWEST WYOMING...Lowered CIGs will persist into the evening ahead of a cold front spreading through the forecast area. Snow showers associated with this storm are expected to move into northern Utah and southwest Wyoming around 23z this afternoon, gradually moving southward through the remainder of the evening. These showers may bring periodic MVFR/IFR conditions to northern Utah terminals through early Wednesday morning. Winds will remain light through the day except for lingering gusts at EVW, until a cold front moving through the region this evening and overnight brings increased northerly winds into Wednesday. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ Kruse/Verzella For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity