textproduct: Salt Lake City

KEY MESSAGES

- Patchy fog has developed early this morning across portions of the Wasatch Back and southwest Wyoming, with a low chance of further development along the Wasatch Front before sunrise.

- Additional showers will develop Friday afternoon across primarily southern Utah, with generally light accumulations.

- High pressure will bring dry conditions for the upcoming weekend before a more active pattern returns beginning Monday as a series of storm systems impact the area. These storms may bring significant mountain snowfall as well as minor valley snow accumulations.

DISCUSSION

An upper-level trough will continue to shift into Utah this morning, ushering in a drier, more stable air mass in behind it. Ahead of this weakening system, scattered showers have developed across roughly the southern third of Utah early this morning, and will overspread much of southeastern Utah through the day. These showers will likely remain fairly weak, though a few may see some better vertical development this afternoon given some lingering instability.

Across northern Utah and southwest Wyoming, patchy dense fog has developed in some areas, though low stratus is likely inhibiting this fog from becoming more widespread across valleys. The fog that has developed will likely last through about mid-morning across portions of the Wasatch Back, particularly in the vicinity of Park City and Parley's summit where visibility lower than a quarter mile has been observed. Cloud cover overall will dissipate through the day as the trough axis passes overhead, which could result in valley fog returning on Friday night in prone locations such as the Cache Valley or near reservoirs.

As ridging builds across the area this weekend, temperatures will rebound to around 10-15 degrees above normal by Sunday and Monday, with increasing southwesterly flow as a potent trough dives southward along the west coast. On Monday and Tuesday, winds could approach advisory criteria primarily across western valleys given 700-mb winds around 40-50kts. Current guidance suggests a 40-60% chance of reaching advisory criteria (45 mph) on both days across western Millard and Iron counties.

This broad trough will remain a feature over the western US through the work week, with a couple of strong shortwave troughs rotating through the flow and likely ejecting across Utah and northern Arizona. The first wave is expected to swing across the area late Monday into Tuesday, accompanied by a surge of moisture and colder temperatures from the southwest. This will mark the initiation of precipitation statewide. Strong moist, southwesterly flow will likely last through at least Wednesday, thus higher terrain favored in southwest flow could do quite well during this period. The second wave, while still somewhat far out, is favored to arrive in the Wednesday-Thursday timeframe, bringing a second cold front with even colder temperatures and northwest flow.

Details still need to be ironed out, however model consensus suggests this pattern could bring significant mountain snow accumulations and a transition to long-awaited valley snow for all but St. George.

REST OF UTAH AND SOUTHWEST WYOMING

Moisture and calm conditions have resulted in patchy fog impacting some northern valley terminals. Expect this to begin to clear up in the hours following sunrise, but patchy fog will once again be possible across northern valleys Friday night given calm and mostly clear conditions. At southern terminals, departing system will result in another day of scattered showers through Friday, beginning to clear out Friday night into Saturday morning. Winds will generally remain light at area terminals, with many following diurnally normal directional patterns.

SLC WATCHES/WARNINGS/ADVISORIES

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