textproduct: Salt Lake City

KEY MESSAGES

- A period of valley rain/snow and heavy mountain snow will accompany a cold front passage on Thursday. High elevation snow lingers across northern and central Utah mountains through Friday.

- Wrap-around showers on Friday morning bring additional chances for accumulating snowfall to valley floors, with lake enhanced showers possible for portions of the Wasatch Front.

- Dry and mild conditions expected this weekend, with another cold storm possible early to mid next week.

DISCUSSION

Dry conditions with more seasonable temperatures are expected today behind the exiting weather system that brought widespread precipitation to northern Utah and southwest Wyoming. Benign conditions areawide will be brief as an upper-level shortwave trough currently off the coast of the PacNW begins moving inland on Wednesday. Increasing southwesterly flow aloft ahead of this system will bring gusty winds to west- central and southwest Utah on Wednesday, with strongest gusts 25-30 mph in the afternoon and evening. This warm, southwesterly flow will also support highs around 10 degrees above average areawide on Wednesday.

A strong cold front associated with this shortwave moves in from the northwest early Thursday morning, with a band of heavy precipitation accompanying its passage. Snow levels beginning around 7500-8000 feet will quickly drop to around 4500-5000 feet with the frontal passage early-to-mid Thursday morning, supporting the potential for heavy, wet snow to mix down to valley floors across northern and central Utah under this band. Given the warm antecedent conditions, morning commute impacts will be limited to areas like Parleys Canyon, though can't rule out the potential for some slick spots under more convective showers especially for the I-15 corridor across central Utah where best dynamics are favored.

After the frontal passage, a general lull is expected with precipitation becoming more showery areawide. Strong northwest flow develops behind the front late Thursday, with widespread gusty northwesterly winds 25-30 mph expected across the entire region. This northwest flow may favor terrain enhanced showers across the higher terrain of northern and central Utah during this period, notably across the Upper Cottonwoods and Tushars. Late Thursday, models show good agreement on the wave pinching off into a closed low overhead before diving southward into the Baja Peninsula. This portion of the forecast is where details become a bit murkier. There is potential for enhanced shower activity to reinvigorate around this low, especially across northern Utah and southwest Wyoming late Thursday into Friday morning. With snow levels well-below valley floors at this point given strong cold air advection behind the front, this may bring a period of better chances for accumulating snowfall to valleys including the Wasatch Front. There is even a 40% chance for lake enhanced showers to impact portions of the Wasatch Front, particularly across Davis, Salt Lake, and Tooele counties. Something to watch as we get closer given the potential impacts for the Friday morning commute.

Wrap around showers may linger through Friday afternoon especially across northern and central Utah mountains before moisture associated with the low moves out of the region. Dry conditions are expected to linger through the weekend as the low parks over the Baja Peninsula and a ridge develops poleward of the low. This pattern will result in dry conditions with more seasonable temperatures lingering into early next week. Ensemble clusters are showing some indications for a cold storm to impact the region sometime around the Tuesday to Wednesday timeframe, but impacts are unclear at this time given uncertainty of the track of this system.

REST OF UTAH AND SOUTHWEST WYOMING

CIGS will gradually lift and scatter out across valley locations through the morning, with a return to widespread VFR conditions anticipated by mid to late afternoon at most terminals. Light and variable winds will transition to southerly at most site tonight through the day on Wednesday.

SLC WATCHES/WARNINGS/ADVISORIES

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