textproduct: Salt Lake City

KEY MESSAGES

- A mild, stable and dry pattern will continue through Thursday. These conditions will support valley inversions and some locally hazy conditions.

- A brief period of unsettled conditions return to the southern half of Utah Friday and Saturday. Modest snow accumulations are anticipated for the southern mountains.

- A cold frontal passage will bring colder conditions into the region during the weekend. It will also support potential for a period of gap winds across portions of southwest Utah Saturday, with roughly a 10-20% chance of gusts in excess of 45 mph noted at this time.

DISCUSSION

Another fairly unremarkable night across the local forecast region. That said, at least some evidence of upcoming pattern change noted in this morning's mid level water vapor loop as a trough is gradually churning towards the Pacific coast. The corresponding increase in mid/upper level moisture is in turn resulting in some increase to cloud cover filtering through overhead.

While the aforementioned trough will continue to slowly approach, the pattern overhead will not change substantially through Thursday aside from the increased cloud cover. Temperatures will continue to run above seasonal normal, and dry and stable conditions will maintain potential for valley inversions and some increase to locally hazy conditions. Overall though, not expecting anything much in the way of impactful weather.

Friday and Saturday continue to appear as the small period of the forecast where slightly more unsettled weather returns. As has been the trend over the prior several forecasts, the cutoff trough responsible for this has continued to trend southward, with any potential phasing with a deepening northern stream trough also still favored across the southern half of Utah. As such, precipitation chances only really increase across the southern half of the state, especially along/south of the I-70 corridor. Even then, there isn't really an abundance of moisture to work with, and forecast water amounts continue to look fairly meager. As evidenced by NBM 25th percentile water amounts near zero, a fairly dry scenario is still very much possible. 75th percentile amounts bring a more broad brushed 0.20" to 0.40" or so for southern mountains, and somewhere in the middle of that seems reasonable. Corresponding snow levels do support high elevation snow, with current forecast carrying around 2" to 6" for southern mountains. While modest for winter standards, some travel impacts will be possible primarily for those higher elevation routes/passes.

While continental and fairly dry in nature (excepting where it can interact with the cutoff's moisture), the deepening northern stream looks to push a cold frontal boundary southward Friday night through Saturday. This will bring a fairly marked cooldown with it, with temperatures falling back to near to a bit below normal through the weekend. Given the mild nature of the season thus far, it'll certainly feel colder if nothing else. That said, there is still some spread on just where the cold air with the deepening trough spills, with some guidance suggesting more of a glancing blow. As such, would not be surprised to see the exact temperature forecast numbers change a bit in coming cycles.

The other primary note to the aforementioned cold front will be potential for enhanced gap winds for a period following passage Saturday, primarily across portions of southwest Utah. Given the previously highlighted uncertainty on the exact depth/placement of the cold air, there is similar questions to the orientation and strength of the associated pressure gradient that would drive these gusty winds. For now, generally expect some gusts in typical favored areas in the 25-40 mph range, with around a 10-20% chance of gusts in excess of 45 mph noted at this time.

Following the departure of this system and trough, the pattern is still favored to return to something more resembling what we've been more or less largely experiencing. While there is still some individual members suggesting some sort of something, general ensemble means support a return to anomalous positive mid level heights across much of the W CONUS (favoring ridging and high pressure). As such, both CPC 6-10 day and 8-14 day temp/precip outlook continue to favor above normal temps and below normal precipitation.

REST OF UTAH AND SOUTHWEST WYOMING

VFR conditions expected for all regional terminals today. Overall light, terrain driven winds prevail for all regional terminals except KEVW where gusty westerly winds are expected to develop this afternoon. Mid-to-high level cloud coverage is expected to increase across the airspace this morning into the afternoon before clearing out across northern Utah overnight.

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SLC WATCHES/WARNINGS/ADVISORIES

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