textproduct: Salt Lake City

KEY MESSAGES

- Valley rain and accumulating mountain snow will spread back across much of the area late tonight through Monday.

- Freezing temperatures will return for some Utah valleys Tuesday and Wednesday morning.

- A warming trend will follow for the latter half of the week into the upcoming weekend.

UPDATE

The shortwave trough which brought widespread valley rain and mountain snow across the forecast area over the past 24 hours is translating through the central Rockies this evening. Weak large scale subsidence in its wake has allowed precipitation to largely taper off across most of the forecast area. However, the next shortwave trough already digging into the western Great Basin is spreading ascent across northern and central NV where showers have developed and are beginning to spread into west central Utah. This shower activity will spread into more of west central and southwest Utah later this evening through tonight, before spreading into northern Utah Monday morning. The band of heaviest precip Monday looks to set up across eastern Tooele County into northern Utah and most of Salt Lake Counties through much of the day, with activity will spread across the forecast area later tonight through much of the morning and early afternoon.

00Z guidance is largely in line with the previous forecast, thus no major adjustments have been made and the previous discussion is included below. With colder air spreading into the region behind this system, a Freeze Watch was issued earlier for most central and southwest valleys.

DISCUSSION

Radar returns and activity have been paltry across Tooele and Salt Lake valleys this morning as southerly flow has led to some downsloping. However, other locations, such as the northern Utah county and the northern Wasatch Front don't have to deal with this problem. These locations have picked up 0.25 to as much as 1.00 inches of rain so far. The storm is far from over though as it is pivoting across the Wasatch Front. As it does so, our southerly winds will gradually transition to more westerly/northwesterly and areas that have missed out will start to fill in. Mountain snow has generally be across elevations above 8000 feet with accumulating snow primarily above 9000 feet. Heavier cells, with some embedded convection, have resulted in quick road slush ups. But as the rates come down with these road snow should quickly dissipate.

A lull in precipitation will start around 6pm as the low ejects to the east, but another trough will be moving into the Great Basin with widespread precipitation forming by Monday morning. Current guidance shows a line of heavier precipitation developing from Dugway up through Salt Lake and into southwest Wyoming that will push to the east throughout the day. Instability appears to be slightly better tomorrow afternoon that could lead to some stronger convection that could produce some gusty winds and frequent lightning. Snow levels will also drop down to 6500 to 7000 feet as H7 temperatures drop closer to -5C. This will allow for some quick slush ups on mountain routes, primarily above 8000 feet. A bulk of precipitation will push out by Tuesday, but diurnal showers will remain across the northern zone through Thursday as shortwaves round the base of the trough across southern Canada.

As colder air moves in behind this second trough, freezing conditions will return to some Utah valleys Tuesday and Wednesday morning. Tuesday morning will see the widespread freezing conditions with most central/southwestern, and eastern valleys experiencing freezing conditions. Slightly warmer temperatures on Wednesday morning will limit the freezing temperatures to areas across Sanpete/Sevier valleys and the western Uinta Basin.

Drier and warmer conditions will return by the end of the week and into the weekend as low amplitude ridge builds across the area.

REST OF UTAH AND SOUTHWEST WYOMING

VFR conditions will prevail through tonight across all terminals. Periods of rain will spread across the area Monday morning, and persist into the afternoon hours, reducing conditions into the MVFR category at times. KEVW will see periods of snow reducing conditions into the IFR category. Conditions across the region will begin to improve after 21Z Monday.

SLC WATCHES/WARNINGS/ADVISORIES

UT...Freeze Watch from late Monday night through Tuesday morning for UTZ114-115-118>120-122.

WY...None.