textproduct: Salt Lake City

SYNOPSIS

A storm system is on track to bring valley and mountain snow to much of Utah Tuesday and Wednesday. A drier Thursday is likely, with models indicating a northern mountain snow event Friday into the weekend.

LONG TERM (After 00Z Thursday/5PM Wednesday)

A strong mid/upper ridge will gradually slide southeast from the Gulf of Alaska over the Pacific to kick off the long term. This will set up a pattern of persistent northwest flow aloft maintaining cool temperatures aloft across our forecast area and maintain favorable storm tracks for the area. On Thursday, mild conditions develop following the departure of our mid-week storm as cool and stable air is transported across the forecast area. Most valley locations will reach highs in the upper 30s on Thursday, slightly below climatological normals for this time of year.

On Friday, enhanced northwesterly flow aloft develops as a shortwave trough ejects from the Gulf of Alaska into southwest British Columbia, flattening the ridge as a result. Ensemble guidance remains in great agreement with this solution, with each cluster remaining in agreement with respect to the general flow pattern, though slight differences in geopotential heights exist and likely won't have much of an impact. At the surface, flow will clock to southwesterly drawing up ample moisture ahead of the northwesterly enhancement. With favorable ascent expected with this impulse, a potentially significant snowfall event appears possible across our northern UT mountains beginning as early as late Friday night through Sunday morning.

Warm air advection commences Friday, serving to raise snow levels across the forecast area keeping any snowfall isolated to higher terrain. Snow levels are expected to drop somewhat heading into Saturday, though not by a large margin. With this type of system, the warm air advection regime will typically keep snow levels above valley floors yielding a relatively high-confidence forecast for rainfall across the majority of valley locations across northern UT this weekend. There is a small chance for some accumulations across the Cache valley as they remain somewhat sheltered and will remain colder overnight into Saturday, though this remains uncertain at this time. There is also a chance that the northern Wasatch Front could see light accumulations as well, granted overnight temperatures cool efficiently. On Saturday, deeper moisture and stronger ascent continue pushing into the forecast area. This is expected to yield higher snowfall rates across our northern mountains, tapering off into the evening as the system progresses southeast into Sunday morning.

Through the extended, ensemble guidance keeps the general pattern in place, though uncertainty remains surrounding the placement of the Pacific Jet. Around 50% of ensemble members build the aforementioned mid/upper ridge, nudging the jet slightly north thus lowering chances for additional precipitation somewhat. Additionally, 25% of members keep the pattern relatively the same with the final 25% of guidance flattening the ridge further pushing the jet slightly south, favoring precipitation chances across central and southern UT in the extended.

REST OF UTAH AND SOUTHWEST WYOMING

Generally VFR conditions are expected across most areas into tomorrow morning. However, some far northern Utah locales may see occasional MVFR CIGS overnight. Otherwise, scattered flurries or light snow are expected to develop across northern Utah tonight and southern Utah tomorrow morning which could lead to to isolated MVFR conditions. Snow showers will then increase across northern and central Utah tomorrow afternoon and evening which could result in periodic MVFR to briefly IFR conditions and mountain obscurations.

SLC WATCHES/WARNINGS/ADVISORIES

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