textproduct: Salt Lake City

KEY MESSAGES

- High-based showers and thunderstorms will develop across southern Utah late Sunday afternoon and evening. Wind gusts up to 50 mph are possible near high-based convection.

- This threat will shift into northern Utah Monday afternoon and evening, with a chance for microburst winds up to 50 mph near any high-based showers and thunderstorms.

- Unsettled conditions will continue through midweek, with the increasing potential for a return to summer-like temperatures late in the workweek to the next weekend.

DISCUSSION

Showers have diminished this evening as a shortwave trough exits to our southeast. In its place, high pressure continues to build across the region, resulting in temperatures rising to around 5-10 degrees above normal this weekend. Tonight, however, expect one more night of freezing temperatures across portions of central and southwestern Utah, with Freeze Warnings out for the Sanpete/Sevier valleys as well as much of the I-15 corridor between Nephi and Cedar City.

As a strong closed low starts to slowly pivot into California on Sunday, mid-level moisture will begin to increase ahead of this system into southern Utah. High-based showers and thunderstorms will increase in coverage from the southwest, though there are still some timing uncertainties with how quickly this moisture moves into the area. Initial high-res guidance suggests scattered showers by mid afternoon or evening Sunday, primarily limited to the southern two-thirds of the state. Although instability doesn't look terribly impressive, only on the order of around 100-200 J/kg, that could still be enough to produce a couple gusts in the 35-45 mph range given a pretty solid inverted-V in model soundings. Current HREF max shows wind gusts up to 45 mph through the afternoon (evening is outside of its window), though gusts may be higher moving into the evening hours as moisture continues to increase.

As this closed low shifts closer Sunday night, showers will push northward under strengthening upper-level diffluence. Precipitation coverage will increase on Monday, primarily across northern areas, given overall synoptic support coupled with daytime heating...as long as cloud cover doesn't inhibit instability too much. Gusty outflow winds could once again be a threat, though model soundings show a bit more low-level moisture which could potentially limit that threat.

Showery activity will then continue statewide through Tuesday and perhaps into Wednesday as well as that closed low moves across northern Arizona. Forecast uncertainty increases here, as models are still struggling with timing differences. Around half of ensemble members favor a slower solution, which could result in showers hanging around a bit longer into Wednesday. Afterwards, high pressure is expected to rebuild into the region, with higher confidence in temperatures continuing to gradually increase.

REST OF UTAH AND SOUTHWEST WYOMING

The airspace will see VFR conditions through the night with mostly clear skies. Across the area, winds will be primarily light and terrain driven.

SLC WATCHES/WARNINGS/ADVISORIES

UT...Freeze Warning until 9 AM MDT Saturday for UTZ116-118-119-122.

WY...None.