textproduct: Salt Lake City

KEY MESSAGES

- Light valley rain and mountain snow is expected across central and southern Utah today, with impacts mostly confined to mountain routes.

- A cold front tracking in from the north will bring chances for light snow with minimal accumulations late today into Saturday, in addition to some of the coldest temperatures of the season Sunday morning.

- Gap winds develop behind the front for favored areas of southwest Utah Saturday into Sunday.

DISCUSSION

Radar imagery this morning depicts showers ongoing across central and southern Utah, associated with an area of deformation developing as a cutoff low moving into the Baja Peninsula phases with a northern stream trough over the northern Plains. Showers will likely remain elevated this morning, producing primarily virga, given high dewpoint depressions over the area. Mid-level moisture will continue to work into the region through the day, allowing a more organized deformation band to develop roughly parallel to the I-70 corridor by late morning. This band will continue to pivot southeastward through the remainder of the day, exiting the region overnight. Given snow levels between 6000-7000 feet during this period, any impacts will likely remain confined to slush-ups on mountain routes across central and southern Utah. Snow accumulation will be overall on the lighter side, generally 1-4 inches for most of the central and southern mountains.

A frontal boundary associated with the northern stream trough is expected to sweep through from the north the latter half of the day into early Saturday. While this system will be quite moisture starved given the continental airmass, we could see some flakes flying this evening mainly for northern Utah mountains, spreading southward overnight into Saturday morning. Any accumulations will be light with minimal travel impacts anticipated. Strong cold air advection should work to scour out any remaining valley inversions. Northerly flow behind this frontal passage will also result in the development of gap winds across favored areas of southwest Utah, especially the Black Ridge Canyon where there is a 50-60% chance for winds in excess of 45 mph late Saturday into Sunday morning.

Northerly flow prevailing behind the cold front in addition to clearing skies overnight Saturday will result in some of the coldest temperatures of the season for Utah and southwest Wyoming on Sunday morning. Expect lows in into the mid-to-upper teens for most valley locations, except the Wasatch Back and lower Washington County, where lows are expected to dip into the single digits and low 20s respectively.

Dry and mild conditions return early next week as high pressure gradually builds back in across the western US. This pattern will also support strengthening valley inversions and subsequent air quality reductions and haze, especially by Tuesday as the ridge axis moves overhead. Weak shortwave troughs brushing the region the latter half of the week may bring periods of improvement.

REST OF UTAH AND SOUTHWEST WYOMING

VFR conditions expected for all regional terminals through Friday with generally light, terrain driven winds. There is a 20% chance VIS temporarily falls into the MVFR range around sunrise this morning at northern Utah terminals. A cold front moving through northern Utah late this afternoon and this evening will bring a 30% chance of light snow accompanied by low end MVFR/IFR conditions. Little if any accumulation is expected. Across southern Utah scattered showers will develop after 18Z Friday with snow levels above 6000 feet.

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SLC WATCHES/WARNINGS/ADVISORIES

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