textproduct: Salt Lake City

KEY MESSAGES

- Building high pressure will maintain dry and increasingly mild conditions into early next week.

- A system will move through the area late Tuesday through Wednesday, bringing valley rain and mountain snow primarily to the northern half of the forecast area.

DISCUSSION

A fairly pleasant start to the weekend across the forecast region today. Temperatures are running near to slightly below normal for southwest Wyoming and the northern half of Utah, and around 7-15 degrees below normal across southern Utah. This is courtesy of colder airmass associated with the departing system. Visible satellite shows little of note aside from a good bit of snow on the ground and some passing high clouds filtering through overhead.

Deep layer riding will gradually amplify overhead into early next week. As such, high pressure will result in a continuation of dry conditions and support warming temperatures. With the ridging, may see some slight increase to some valley haze, though the increasing effect of the sun angle pushing towards spring should help abate things from getting too thick. Similarly would also anticipate at least some potential for localized fog development overnight in sheltered valleys that hold on to some snow on the ground.

A deep elongated Pacific trough characterized by strong jet jet flow in excess of 140 kts and favorable IVT above the climatological 90th percentile will shift into the region by midweek. The best combination of moisture and dynamics looks to favor the northern half of the forecast region, and as such that is where associated precipitation will be most likely. Warm initial conditions will support elevated snow levels generally in the 7000-8000 ft range, falling closer to 5000-7000 ft following the passage of a cold front late Wednesday. This front will only make it as far south as central Utah or so. Given the limited amount of cold air, and the fact it'll be largely coming as moisture starts to wane, this looks to be another mountain snow and valley rain event. Given the good moisture transport, northern mountains see a 60% chance at an inch or more of water, with valleys at similar odds for more than a quarter inch of rain. Given the strong flow overhead, do think there is some chance strong orographic forcing may lead to some higher localized mountain totals in favored spots, and conversely could lead to some localized downsloping eating away at some areas of valley rain. Looking at ensemble clusters, there is still roughly 17% of membership bringing precipitation to areas further south across southern Utah.

Following the aforementioned system temperatures will rebound and drier conditions return as ridging is reestablished across much of the west. Uncertainty is noted for the weekend though, as models largely support a deepening trough digging southward from the northern Plains, with varying degrees of its western extent and potential timing. Given how far out in time it is, wouldn't put much faith into any numbers and instead would focus on any trends. If nothing else, looking at ensemble plumes for some northern mountain locations at least shows some members with bumps in precip rather than fully flatlining.

REST OF UTAH AND SOUTHWEST WYOMING

VFR conditions will prevail across all TAF sites except KLGU through the period. Diurnal wind shifts are expected across all sites. Following 12z, MVFR vsbys will develop at KLGU, perhaps dropping below 1SM around 15-17z. Conditions will improve by 18z at the latest.

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SLC WATCHES/WARNINGS/ADVISORIES

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