textproduct: Salt Lake City

KEY MESSAGES

- By Saturday, unsettled conditions will return to northern Utah. Showery precipitation along with initially high snow levels will continue through Tuesday.

- A more organized upper level low will cross the region Monday into Tuesday, bringing more widespread precipitation to the state and slightly higher precipitation intensity for northern Utah.

- A colder but less moisture rich system will move through the Great basin later Wednesday into Thursday, with increasing potential for limited lower elevation snow amounts.

DISCUSSION

As ridging crests over the western edge of the forecast area this afternoon, yielding anomalously warm conditions with maximum temperatures for the day running 5-15F above normal for northern utah and 10-15F above normal across central and southern Utah. While the ridge itself decays through the weekend and moisture is able to spill in overhead, there will be little in the way of cold advection given the more zonal orientation of the flow until Tuesday at the earliest where models are in better consensus of a deeper low with more northern origins finally brings cooler temps.

Showery precipitation will begin to spread across northern Utah by late Saturday and continuing through Sunday as a weak shortwave trough ejects out ahead of a lifting upper level low. Continued warm advection during much of this time will ensure high snow levels, with 10th percentile (lowest reasonable) snow levels still up around 8800 ft.

A more significant feature is forecast with relatively high confidence to pass through the area Monday-Tuesday, bringing more widespread measurable precipitation to the area. The ECMWF Extreme Forecast Index does show a signal for anomalous precipitation across portions of northwest through west-central Utah, though the most significant signal sits to our west in northeastern Nevada. Though this is a deeper more progressive wave with colder H7 temps, it is still a much warmer system than we might expect this time of year, and snow levels will remain generally above 6500-7000 ft. The NBM does have a 75% chance of greater than 8 inches of snow in the upper Cottonwoods and Uintas for this storm, but this will mostly occur above 8500 feet, and could be moderated by below-normal SLRs/above-normal snowfall density.

Moderately good agreement in the ensembles highlights another, potentially deeper, progressive wave moving through the area in the Wednesday afternoon through Friday night timeframe. This system does finally tap into some colder Canadian air, which should increase the likelihood for seeing some accumulating snow in the valleys of northern and central Utah. The 13Z NBM is still fairly pessimistic on measurable snow along the Wasatch Front, Cache Valley, Sanpete and Sevier Valleys, and I-15 corridor through central and southwest Utah with < 10% chance of 1".

The active weather pattern then looks to continue for the foreseeable future, though it's hard to discern if any of these systems will be particularly cold or moist.

REST OF UTAH AND SOUTHWEST WYOMING.

VFR conditions will prevail across all of our TAF sites through the period. KEVW will see gusts in excess of 20kts dissipating by 03z.

SLC WATCHES/WARNINGS/ADVISORIES

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