textproduct: Salt Lake City

KEY MESSAGES

- A largely mild, calm and dry pattern will persist through much of the upcoming work week. The stable conditions and redevelopment of local valley inversions will in turn lead to potential for haze.

- The southern mountains could see some modest precipitation later this week in the Friday/Saturday timeframe as a weak system pushes through the region. This system will also act to mix out valley inversions.

DISCUSSION

Utah and southwest Wyoming are currently sitting between a narrow ridge over the west coast and a broad trough encompassing much of the eastern US, resulting in persistent and stable northwesterly flow. A look at this morning's sounding reveals valley inversions still in place, though visibility observations have largely stayed above 6 miles this afternoon despite some visible haze out the window. Dry and stable conditions will continue through at least Thursday, though low chances for fog could develop on Thursday and Friday mornings in favored areas such as the Cache Valley.

By Friday morning, model guidance suggests a shortwave trough developing upstream, which will deepen as it swings across Utah likely sometime on Saturday. Along with this shortwave trough, a closed low will move in phase across AZ, now forecast to take a track even further south. Modest moisture associated with this low ahead of the shortwave trough may produce some light snowfall across the southern mountains between Friday morning and Saturday afternoon, though the best moisture is well to our south so accumulations will be minor at best. The NBM 25th percentile shows nearly 0.00" QPF across the state, though the 75th percentile at least shows up to 0.40" across the southern mountains. This could translate to 3-6" of snow in the highest elevations, mainly south of US-6.

As this shortwave trough passes through, a dry cold front will push across the state, bringing clearing skies, mixing of valleys, and cooler, more stable conditions behind it. There is still some question as to when this cold front moves through the area on Saturday, though it seems likely that we could see some chilly temperatures by Sunday morning...potentially reaching Code Blue criteria along the Wasatch Front. Unfortunately, the pattern will continue to favor ridging over the western US and a mean trough over the eastern US, which doesn't bode well for more snowfall in the near future.

REST OF UTAH AND SOUTHWEST WYOMING

Generally light, terrain driven winds prevail for terminals today except KEVW, where gusty westerly winds are expected to diminish around 00z. Valley haze across the Wasatch Front may result in periodic slantwise visibility reductions this evening into the morning. Otherwise, clear skies yield widespread VFR conditions through the period.

SLC WATCHES/WARNINGS/ADVISORIES

UT...None. WY...None.