textproduct: Salt Lake City

KEY MESSAGES

- After a brief break through early Saturday, an unsettled pattern will shift into northern Utah. Showery conditions, with high snow levels, will continue through Monday.

- An upper level low will cross the region Monday into Tuesday, bringing more widespread precipitation to the state.

- Another colder system will impact the Great Basin later Wednesday into Thursday.

DISCUSSION

A dry and mild northwesterly flow aloft is in place over Utah this evening downstream of an upper ridge with its axis over the West Coast. This ridge will move inland tomorrow and by Saturday afternoon, its axis will be overhead, although by then the ridge will have lost some of its amplitude. Still, this pattern will continue to bring above-normal warmth to the area as temperatures gradually trend warmer through the weekend.

A dry airmass will yield to showery precipitation across northern Utah by late Saturday and continuing through Sunday as a weak ripple ejects out of an approaching upper low. Warm advection during much of this time will ensure high snow levels, largely above 8500-9000 ft. This, combined with the aforementioned showery nature of precipitation should keep impacts on the low side.

The upper low will be arriving for Monday through Tuesday is expected to bring more widespread precipitation to the area. Latest global models indicate some modest cyclogenesis developing across southern Nevada through southeast Utah which could aid in enhancement of precipitation especially across portions of western and northern Utah. The ECMWF Extreme Forecast Index does show a signal for anomalous precipitation across portions of northwest through west-central Utah. However, even in the cooler airmass behind the low, snow levels will remain relatively high, generally above 6500-7000 ft. The NBM does have a 60-70% chance of greater than 6 inches of snow in the upper Cottonwoods and Uintas for this storm, but this will mostly occur above 9000 feet and these chances could be a bit inflated given the NBM snow ratios tend to run a bit high with warmer events.

The next storm, which will follow for the late Wednesday through Thursday night timeframe, will be accompanied by colder air which will increase the likelihood for accumulating snow in the valleys. The 01Z NBM has between a 20-60% chance for measurable snow along the Wasatch Front, Cache Valley, Sanpete and Sevier Valleys, and I-15 corridor through central and southwest Utah. However, amounts will likely be limited as the probability of greater than 1 inch of snow for these same areas remains generally under 30%. Portions of the northern mountains as well as the Tushars have a 50% chance or greater of seeing 6 inches of snow. Overall, however, moisture anomalies with this storm are much more subdued than with the Monday/Tuesday storm. The active weather pattern then looks to continue through the weekend, with model consensus leaning towards another storm which will also be potentially cold enough to produce snow to the valley floors.

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 develop around 19z, dissipating by 03z.

SLC WATCHES/WARNINGS/ADVISORIES

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