textproduct: Salt Lake City

KEY MESSAGES

- After a general lull today, heavier precipitation accompanying a cold front passage Monday into Tuesday morning will bring widespread rain and high elevation snow to northern and central Utah.

- A colder system impacts the region late Wednesday through Thursday, bringing better chances for more substantial mountain snow and potential for light valley snow.

DISCUSSION

A transient ridge overhead today brings continued unseasonable warmth and mostly dry conditions areawide today, with the only exception being scattered showers moving into far northern Utah late this afternoon and evening. Highs this afternoon will top out around 10-15 degrees above average, more reminiscent of a mid-to-late April day... today will be the last day in the warming trend, however, as a cold front makes its way through the region Monday.

A cutoff low currently located off the northern California coast will continue to traverse eastward today, moving inland early Monday. Enhanced southwesterly flow ahead of this system will result in gusty winds developing by late Monday morning, notably across central and southern Utah with widespread gusts between 30-40 mph. A cold front associated with this low is expected to move in from the northwest beginning mid-to-late Monday morning, with a band of heavy precipitation accompanying the frontal boundary as it continues moving eastward through the day, extending as far south as the central mountains. Given warm antecedent conditions, snow levels will begin around 8500-9000 feet at the onset of precipitation, gradually decreasing through the afternoon. Post- frontal northwesterly flow developing late Monday into Tuesday morning will keep showers lingering over northern Utah, with snow levels bottoming out around 6500-7000 feet. As such, could expect a period of lower density snow overnight across northern Utah mountains, notably the Upper Cottonwoods where northwest flow is favored. Overall, impacts will be quite limited with this system, though could see some travel impacts across mountain routes above 7000 feet Monday night into Tuesday morning.

Shower activity wanes areawide by Tuesday afternoon, with cooler, northwesterly flow bringing temperatures closer to seasonal normals. We'll see a break in active weather Tuesday and through a majority of the day Wednesday before an upper-level shortwave trough digging into the Great Basin late Wednesday into Thursday yields cooler and wetter conditions through this period. Initially, this system looked to be quite moisture starved as its origins were favored from a more continental airmass, but recent guidance favors this wave originating from a low over the Gulf of Alaska. As such, this system looks a lot cooler than previous, with a more efficient Pacific moisture tap. This system will bring better chances for more substantial mountain snowfall accumulation, with a 30% chance for 9+ inches of snow accumulation across the northern mountains, except a 70% chance across the Upper Cottonwoods. Across central Utah mountains, there is currently a 30-40% chance for 6+ inches of snow accumulation, except a 60-70% chance for the Tushars. With strong cold air advection aloft associated with this storm, H7 temperatures are expected to fall to around -8 to -11C by late Thursday morning, which will favor snow levels near valley floors. Current guidance maintains low chances (10-20%) for accumulating snowfall across the Wasatch, with higher chances around 50-60% across central Utah valleys given better dynamics in this region.

Friday onward, the pattern remains overall progressive, but ensembles are split on exactly how things will progress as the aforementioned shortwave dives southward into the Baja Peninsula.

REST OF UTAH AND SOUTHWEST WYOMING

Mainly dry conditions expected through the day, with a round of showers possible across northern Utah and southwest Wyoming tonight. Briefly MVFR conditions will be possible in showers, especially at KHCR and KEVW, otherwise predominantly VFR conditions are expected at most terminals. Winds will generally see typical diurnal trends.

SLC WATCHES/WARNINGS/ADVISORIES

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