Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
959 FXUS65 KSLC 152233 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 333 PM MST Mon Dec 15 2025 .KEY MESSAGES... - A landfalling atmospheric river will bring a long duration period of mountain snow and valley rain across northern Utah beginning Wednesday. - Strong, gusty winds will impact Uinta County, WY Wednesday afternoon and evening. && .DISCUSSION...Broad upper level ridging remains in place across the eastern Pacific. A weakening shortwave undercutting the ridge continues to shift eastward across Utah. Attention then turns to the active northern stream and the impacts to northern Utah through much of the remainder of the forecast. As a shortwave trough embedded in strong flow near the US/Canadian border races eastward Tuesday, moist northwest flow will build into northern Utah. Weak cold air advection will continue into Tuesday afternoon. Flow will back in the wake of this system Tuesday evening, before the next jet max takes aim on northern Utah Wednesday. Initial snow levels will be near 8500-9000 feet Wednesday afternoon as preferential jet dynamics support a broad area of moderate to occasionally heavy precipitation over northern Utah. By Wednesday evening, snow levels across northern Utah will fall to 5500-6500 feet, though this will be at the tail end of the period of precipitation. In general, expect 0.25-0.75" of snow water equivalent for the northern mountains, heaviest north of I-80. Snow ratios will be more reminiscent of the Sierra versus the Wasatch, so total snow accumulations will be in general around 2 to 5 inches, locally higher in the western Uintas. There is little threat of snow to valley floors (sorry snow lovers), with less than a 5% chance for accumulating snow for valley floors of the Wasatch Front. After the main forcing once again for precipitation shifts east early Thursday, expect a break in the precipitation until Thursday afternoon when yet another shortwave trough will bring another round of largely light precipitation to northern Utah. This pattern will continue...with another series of shortwave troughs expected to bring rounds of mountain snow and valley rain to northern Utah Friday into early next week. With snow levels largely remaining above 7500-8000 feet, snow ratios will favor dense snow, so while SWE amounts are most likely to range from 0.75-1.50" (25th to 75th percentile) for the northern mountains, snow totals will be closer to 4 to 10 inches from Friday morning through Sunday morning. The one potential headline will be for strong, gusty winds across Uinta County, WY Wednesday. Strong, westerly 700mb flow, near 55-60kts will support strong winds with gusts in excess 50 mph likely. Right now, the probability of wind gusts in excess of 58 mph is roughly 40%, which precluded joining neighboring offices with a High Wind Watch. Something to monitor moving forward. && .AVIATION...KSLC...VFR conditions will persist for the KSLC terminal through the period. Dry conditions will continue with some mid and high level clouds moving in overnight. Winds will remain light out of the north before transitioning to a light southerly wind this evening. There is a 20% chance of fog developing on the north side of the terminal overnight. .REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will persist for the entire airspace through the period. Dry conditions will continue with mid and high level clouds moving in overnight. Winds will remain light and diurnally driven. There is a 20% chance of fog developing overnight for some valley locations across the northern airspace. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ Kruse/Mahan For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity