Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
006 FXUS65 KSLC 091033 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 333 AM MST Tue Dec 9 2025 .KEY MESSAGES... - An atmospheric river will primarily affect the Pacific Northwest through Wednesday. Southwest Wyoming and far northern Utah will be on the southern periphery of this Tuesday and Wednesday, with gusty winds and light mountain snow. - High pressure will be in place Thursday through the weekend, with dry conditions and temperatures around 10-15F warmer than normal. Strengthening valley inversions can be expected, especially by the weekend. && .DISCUSSION...Utah remains under a northwesterly flow aloft this morning downstream of a ridge over the eastern Pacific. A landfalling atmospheric river is currently noted over the PacNW, with moisture streaming into Montana and northern Idaho. The position of the upper jet well north of Utah will keep the bulk of the moisture to the north. However, the northwest flow will pull some remnant moisture into northern Utah today into tomorrow. This moisture is expected to remain fairly limited, with the NBM 25th percentile QPF amounts remaining at 0, while the 75th percentile amounts range from less than 0.1 inches across the central Wasatch and western Uinta Mountains to up to 0.15 inches in the northern Wasatch and around 0.4 inches in the Bear River Range. It should be noted, however, that the HREF amounts are higher, with ensemble means of up to 0.30 inches in the Wasatch/Uintas and locally over 1 inch in the Bear River Range. These models land on the very high end of the NBM probabilistic forecast and thus considered very likely, but cannot be completely ruled out. Nonetheless, snow levels will be high (near 7000 ft today rising to near 9000 ft tomorrow) and snow densities will be low, so snow accumulations are not expected to be significant even if the storm does overperform. Enhanced winds are noted across southwest Wyoming and portions of far northeast Utah this morning, and these winds will increase through the day and continue into tomorrow as a trough over southern BritCol tracks southeast before grazing northeast Wyoming this evening. Models continue to indicate H7 winds of up to 55kt across southwest Wyoming along with a westerly surface gradient. However, the probability of reaching High Wind Warning Criteria in both the NBM and the HREF remains generally under 15%. Given this probabilistic information, along with the trough position well to the east and model soundings not even mixing up to the H7 level, it seems reasonable to go without any wind highlights. Dry and above normal temperatures can be expected Thursday through the weekend as the upstream ridge builds and very slowly shifts inland. As the flow weakens, especially over the weekend, expect inversion conditions to strengthen, although the lack of both snow cover and pre-existing cold air will help moderate this somewhat. For those looking for the next storm, global deterministics are all trending towards a relatively weak trough next Tuesday. This solution remains in the minority based on cluster analysis of global ensembles, but it`s...something. && .AVIATION...KSLC...VFR conditions will persist for the KSLC terminal through the period. Dry conditions will continue with mid level clouds increasing during the day. Light southerly winds will transition to light northerly winds during the afternoon. .REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will persist for the entire airspace through the period. Mid level clouds will increase across the northern airspace with some light mountain showers in the evening across the far northern mountains. Elsewhere, conditions will remain dry with light and diurnally driven winds with stronger winds across the higher terrain in the northeast. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ Cheng/Mahan For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity