textproduct: Salt Lake City

KEY MESSAGES

- Locally critical fire weather conditions may return to portions of southern Utah Saturday and Sunday afternoons.

- Temperatures will drop to around 10 to 20 degrees below normal Sunday into Monday as a cold storm system moves through the area. Accumulating snow is possible across the northern mountains and mountain valleys along with southwest Wyoming.

- Freeze conditions will impact many Utah valleys outside of the Wasatch Front Monday and Tuesday mornings, and even as early as Sunday morning in the Cache Valley and Wasatch Back. Some areas may see a hard freeze including the Cache Valley, Wasatch Back, west central and southwest Utah and the Sanpete Valley.

DISCUSSION

A near-zonal flow is in place over Utah this evening, with mostly clear skies and mild temperatures accompanying. Expect similar conditions for Friday, with perhaps a bit more midlevel clouds across southern Utah. The pattern will then shift for the weekend, with cooler and wetter conditions expected.

This pattern shift will begin on Saturday with a shortwave trough moving across the PacNW, while a weaker southern branch disturbance approaches Utah and Arizona. Southwesterly winds will increase across southern and eastern Utah by Saturday afternoon, while a cold front crosses northern Utah. The winds across southern Utah could bring localized critical fire weather conditions. Near the cold front, showers are expected to develop, mainly over and near the higher terrain. These will be largely high-based and precipitation amounts are not expected to be significant, as even at the 90th percentile, the NBM QPF largely remains under 0.25 inches except over the high Uintas where it has closer to 0.45 inches.

As the PacNW trough continues to dive into Utah on Sunday, increasingly cooler air will spread into the area. High temperatures in many valleys across northern Utah on Sunday and across northern, central, and southwest Utah on Monday will likely fail to reach 60F. This would be 15-20 degrees below climatological normals. Additionally, precipitation will become more widespread Sunday into early Monday morning. Precipitation amounts from the NBM mean have been trending upward with the last few model runs. However, there is still quite a bit of model spread, especially across northeast Utah, southwest Wyoming, the central Utah mountains and portions of the Wasatch Front. For example, the 25th-75th percentile at SLC ranges from 0.07-0.84 inches. This model spread would affect snow fall amounts as snow levels are expected to fall to near 6kft, bringing the potential for snow to the mountains and some of the higher valleys. Snow amounts of 6 inches or more will be most likely over the upper Cottonwoods and the western Uintas, otherwise most other mountain areas are currently expected to see 4 inches or less, with generally 3 or less in higher northern valleys such as the Park City area and across southwest Wyoming.

With the cooler air settling into the area, there will be the potential for another round of freezing conditions, especially across central through southwest Utah Sunday night/Monday morning and Monday night/Tuesday morning. By Tuesday afternoon, temperatures are expected to start trending upward again as drier conditions spread back into the area. However, there remains a fair amount of model spread, with cluster analysis of ensemble members showing varying patterns including troughiness, ridging, and near-zonal flow over the western CONUS by the middle of next week.

REST OF UTAH AND SOUTHWEST WYOMING

VFR conditions will persist through the TAF period. Winds will remain light and terrain driven through mid-morning Friday. Northwest winds will develop by late Friday morning across most northern TAF sites, while southwest winds will be the rule Friday across southern Utah.

FIRE WEATHER

Conditions will stay dry and become increasingly mild through Saturday, with highs peaking at 5F above normal for this time of year. Winds will pick up Saturday afternoon ahead of the next approaching storm system, and these breezy winds could combine with the dry conditions to produce locally critical fire weather conditions. The storm system, quite unseasonably cold, will cross the area Sunday into Monday. Temperatures are expected to drop to up to 20F below seasonal normals by Monday morning. Snow levels are forecast to drop to as low as 5000 feet by Monday morning, with up to six inches of snow possible for the highest elevations of the northern mountains. Accumulations look to be far less over central and southern Utah. Drier conditions are then expected to follow Tuesday behind the front, with generally dry conditions persisting through next Thursday.

SLC WATCHES/WARNINGS/ADVISORIES

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