textproduct: Salt Lake City

KEY MESSAGES

- Gusty south to southwest winds up to 50 mph will impact most eastern valleys 10 AM to 6 PM Wednesday.

- Strong northwest winds up to 55 mph will develop behind the cold front across Castle Country near and along the SR-10 corridor after 1 PM and continue through 5-6 PM Wednesday.

- Northern valley rain up to around 0.25" and northern mountain snow of around 2 to 6 inches (locally higher over the Bear River Range) will occur between Wednesday morning and Thursday evening.

- Freezes will impact central and southwest Utah valleys Wednesday night into Thursday morning, expanding to include eastern Box Elder County Thursday night into Friday morning.

DISCUSSION

An upper low is currently noted off the OR/CA coast. Meanwhile, a shortwave trough rotating around the low is ejecting across the central/southern Sierra Nevada. Downstream of this trough, Utah remains under a warm and fairly dry southwesterly flow aloft. Gusty winds were prominent today especially across the western valleys, with many gusts in the 40 to mid-50 mph range. Ahead of the approaching trough, winds will remain at least locally gusty through the night, but otherwise should weaken somewhat as they decouple.

The trough will eject across northwest Utah, pushing a cold front through the forecast area early Wednesday morning through Wednesday afternoon. Winds are expected to remain gusty across southern and eastern Utah ahead of the frontal passage Wednesday, then favored downslope areas such as the eastern Uinta Basin and Castle Country are expected to continue to see gusty winds behind the cold front.

Precipitation will fill in behind the front, but limited to northern Utah and southwest Wyoming north of the associated upper jet. However, hi-res guidance suggests precipitation to be fairly showery, so amounts are not expected to be very significant overall, especially south of areas near the Idaho border. Showery precipitation will continue into Thursday, as the aforementioned upper low is forecast to shear apart and ripple through in pieces. While cooler air will settle into the area, snow levels will remain off most valley floors, bottoming out near 6kft. Snow amounts are likely to remain below advisory criteria for most mountain areas, except perhaps along the highest ridgelines, which should have little impact.

As clouds scatter out Wednesday night, good radiative cooling will allow overnight temperatures to cool efficiently. As such, expect freezing temperatures especially across the valleys of central through southwest Utah Wednesday night/Thursday morning and potentially again the following night. This will have an impact on early season agriculture.

Another shortwave trough is expected to dive south through ID and western MT, arriving at the doorstep of northern Utah by Thursday evening. Latest models don't have it going farther south than that, limiting the chances for precipitation on Friday. The pattern becomes active again late Saturday into next week. The next trough arriving from the southwest looks to bring potentially more widespread precipitation to the area Saturday night into Sunday. Beyond that, the large-scale pattern becomes more complex, but cluster analysis of model ensembles lean towards overall troughiness near the West Coast.

REST OF UTAH AND SOUTHWEST WYOMING

VFR conditions will persist for the entire airspace through the period. Gusty southerly winds will persist for most terminals overnight before a cold front moves through the region tomorrow morning transitioning winds to a west/northwest flow. Scattered showers will exist throughout the day for the northern airspace with dry conditions across the southern airspace.

SLC WATCHES/WARNINGS/ADVISORIES

UT...Freeze Warning from 10 PM Wednesday to 10 AM MDT Thursday for UTZ114>116-118>120-122.

Wind Advisory from noon to 6 PM MDT Wednesday for UTZ120.

Wind Advisory from 9 AM to 6 PM MDT Wednesday for UTZ121-128>131.

WY...None.