Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
053 FXUS65 KSLC 222248 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 348 PM MST Sat Nov 22 2025 .SYNOPSIS...Patchy dense fog is possible across northern Utah valleys and southwest Wyoming tonight. A weather system moving through the Four Corners on Sunday brings light precipitation to far southeast Utah, with the remainder of the state remaining dry into early next week. && .DISCUSSION...Key Points: - Patchy dense fog may result in visibility reductions to less than a quarter mile tonight across some northern Utah valleys and southwest Wyoming. - Generally dry conditions expected through at least Thanksgiving Day, outside of some light precipitation across far southeast Utah on Sunday. - A dry cold front passage late Monday will bring much cooler temperatures Tuesday. Day cloud phase satellite imagery shows low stratus decks eroding across northern Utah valleys and southwest Wyoming this afternoon. As such, much of the northern portion of the forecast area will see clear skies this evening, which will be supportive for the potential for another night of fog development in these areas. Limiting factors tonight include slightly lower dew points areawide today, which may keep any fog development at bay. Thus, certainty in locations of dense fog overnight tonight is quite low, though these conditions suggest coverage would likely be less than the past few nights. Some light valley rain and high elevation snow showers are going on across southern Utah this afternoon per recent radar imagery, associated with moisture wrapping around a low pressure system currently centered across the northern Baja Peninsula. Accumulations from these showers will be little to none given drier air at the surface. These showers will continue to move northwestward into Nevada through this evening. As this low lifts northeast and across the Four Corners region through Sunday, additional shower activity is expected to fill in across southern Utah overnight into Sunday morning, though these showers remain light as the region remains on the fringes of main moisture transport. Best chances for measurable rainfall will exist east of the US-89 corridor and south of the US-12 corridor, where storm total accumulations of up to a tenth of an inch of precipitation is possible. Higher elevation locations may see upwards of 0.2-0.25". A shortwave trough moves in from the Pacific Northwest on Monday, traversing the northern Rockies through Tuesday, This system will bring a dry cold front passage to the region late Monday, yielding a cooldown of around 5-10 degrees for Tuesday. Some of the coldest lows of the season are also likely across portions of southern Utah, mainly on Wednesday morning as the development of gap winds through the Black Ridge Canyon from northerly flow behind the front will keep lows elevated on Tuesday morning. For lower Washington County, where there is a 15-20% chance for lows to reach freezing on Wednesday morning. Overall dry conditions prevail through the remainder of the week behind this front, with the exception of the potential for light, orographic-enhanced snow showers across the Bear River Range and portions of the Wasatch on Monday as northwesterly flow prevails behind the front. Expect conditions to remain dry and mild areawide on Thanksgiving Day. A shift in the pattern across the western US appears likely next weekend per long-range ensembles. These ensembles indicate some flavor of deep troughing developing across the west Saturday into Sunday, which will bring cooler temperatures in addition to the potential for more widespread precipitation chances. There is a bit of variability in the placement of this trough, as it will heavily depend on the placement of an upstream North Pacific ridge. At this time, ensembles exhibit a near 50/50 split on potential scenarios. The first scenario is the colder and wetter scenario in which a deep trough digs into the Great Basin Saturday into Sunday. The other scenario takes this trough further east into the Rockies, which would yield drier, milder conditions. && .AVIATION...KSLC...Northwesterly winds will persist until a transition to southeasterly around 03-04z. Fog chances will return once again late tonight and into early tomorrow morning. After 06z, patchy fog will begin to develop over the lake, resulting in a 30% chance for dense fog and LIFR conditions between 11-16z if the fog is able to move over the airfield. Similar to today, may see some MVFR SCT-BKN cloud decks lasting through much of the morning, likely dissipating after 18-19z. .REST OF UTAH AND SOUTHWEST WYOMING...Across southern Utah, showers will increase in coverage after 08-10z, mainly for areas east of KBCE and south of KHVE, resulting in MVFR-IFR conditions at times. These showers will likely continue through the morning, dissipating through the afternoon as the low pressure system continues eastward. Across northern Utah and southwest Wyoming, expect patchy dense fog/LIFR conditions to redevelop across certain valley locations after 03-06z, with the highest chances in the Cache Valley, Heber Valley, near KEVW, and areas close to the Great Salt Lake between KSLC and KBMC. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ PUBLIC...Whitlam AVIATION...Cunningham For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity