textproduct: Salt Lake City

KEY MESSAGES

- Freezing conditions will occur across central and southern valley locations tonight into Wednesday morning.

- A strong cold front will bring accumulating valley snow to northern Utah Thursday afternoon into Thursday night, with snow showers continuing into Friday morning. Snow may impact both the Thursday evening and Friday morning commutes along the Wasatch Front.

- Very cold temperatures in the teens to upper 20s will occur across most valleys of Utah Thursday night into Friday morning and each subsequent overnight period through Sunday morning. Temperatures this cold can freeze sprinkler systems and cause widespread fruit orchard blossom death. Consider re-winterizing sprinkler systems to avoid property damage.

DISCUSSION

An upper level low that brought widespread mountain snow and even a few inches to southern valley locations such as Cedar City will continue to pull away from the region this afternoon. With a colder airmass in place under generally clear skies, one more night of freezing temperatures will occur in many central and southern Utah valleys. Freeze Warnings remain in effect for these locations.

Attention then turns to a very cold, robust trough dropping south and east into the Interior West on Thursday. The associated cold front will cross into northern Utah late Thursday morning into early Thursday afternoonreaching Salt Lake City between 3 and 6 PM. Any rain will quickly change to snow as snow levels fall to valley floors. This will likely bring accumulating snow to a portion of the evening commute across the Wasatch Front, as well as impact any outdoor activities across the region.

There are some indications in the guidance that this front may be strong enough to have a very intense band of precipitation for 1-2 hours and then a period of subsidence for several hours before snow showers fill back in. These types of fronts tend to limit widespread valley accumulations to around 1-2 inches for the valley floors with higher amounts for the benches. Current NBM 25th to 75th percentile snow totals support these amounts, around 1-2 inches for the valley floors of the Wasatch Front, up to 6 inches benches. Additional snow accumulations will occur in any areas that are impacted by lake enhanced snow showers overnight Thursday into Friday morning. This part of the puzzle is always difficult to discern this far out with how sensitive lake enhancement is to drying in the boundary layer and wind direction. Something to monitor that could allow for higher snow accumulations.

Areas south of about Utah County will see far less precipitation as forcing shifts east as the front reaches these locations. One question mark for locally enhanced totals would be the Nephi to Cedar City corridor, where some ensemble members are suggesting heavier, orographically forced snowfall.

Areas remaining ahead of the front through the afternoon across central and southern Utah will see strong, gusty south to southwest winds up to 45-50 mph. Current ensemble members suggest there is a 50% chance wind gusts will exceed 45 mph for 3+ hours in many of these valleys, which may eventually require a wind advisory as this portion of the forecast shifts to the near-term.

Outside of the fact that the Wasatch Front is experiencing a historically low snow total for the water year and so a few inches of snow will be unusual this year, the portion of the storm that could have even more impact is the very cold temperatures behind the front Thursday night into Sunday. Overnight lows will reach temperatures cold enough in some locations to freeze sprinkler systems that were turned on for the spring during the exceptionally warm spring as well as cause blossom death in fruit orchards. Those who turned on their sprinkler systems across much of Utah may consider re-winterizing, especially those with shallow or above ground pipes.

REST OF UTAH AND SOUTHWEST WYOMING

Mountain obscuration will continue through this afternoon across the mountains of central and southern Utah, but cloud cover will rapidly thin this evening and overnight allowing VFR conditions for all areas. In large, northwesterly winds across the airspace will become light overnight, prior to increasing from the south mid morning Wednesday.

SLC WATCHES/WARNINGS/ADVISORIES

UT...Freeze Warning from 9 PM this evening to 9 AM MDT Wednesday for UTZ114>116-118>122-130.

Winter Weather Advisory until 3 PM MDT this afternoon for UTZ117- 125.

WY...None.