textproduct: Salt Lake City

KEY MESSAGES

- Periods of precipitation, mainly in the form of valley rain and mountain snow, will impact the Beehive State through Friday with temperatures averaging around 5 to 10 degrees above normal.

- The greatest snow accumulation will occur early Wednesday into Thursday across the northern Utah mountains where there is around a 60% chance of accumulations exceeding 9 inches in the Upper Cottonwoods and 6 inches for the remainder of the northern Utah mountains.

- The active weather will continue, with the next round of precipitation increasing in likelihood for the beginning of next week.

DISCUSSION

A low-amplitude trough grazing northern Utah today has pushed a cold front into Utah. This front is currently located near a line extending from Milford to Price and should move into southeast Utah before stalling out this evening. Behind the front, a band of mostly light precipitation in the form of valley rain and mountain snow developed near the H7 baroclinic zone. With the front outrunning the upper dynamics, however, precipitation will be winding down by late this afternoon and largely fail to make it past the northern half of Utah.

Tomorrow, as an upstream low approaches the West Coast, southerly flow aloft will increase, and the stalled cold front will lift back north as a warm front. Generally light valley rain and mountain snow will redevelop along this boundary across northern and portions of central Utah.

Early Wednesday morning through Thursday looks to bring the best chance of widespread precipitation to the forecast area as the low gradually breaks down with various vort lobes ejecting across Utah. Most of this will occur in a breezy and mild southwest flow on Wednesday before the flow turns more westerly to northwesterly by Thursday afternoon. Snow levels will remain high through Wednesday, with valley rain and relatively dense mountain snow. The NBM QPF from Tuesday evening through Thursday afternoon has a 25th-75th percentile range of between 0.9-1.7 inches in the upper Cottonwoods and 0.5-1 inch across the rest of the northern mountains. The NBM snow amounts may be a bit high as it uses a greater than 10:1 average snow ratio, but bottom line is that a period of potentially impactful snow may occur over the northern mountains during this timeframe.

As the trough moves out of the area, there will be a break in the weather Friday into the weekend. An active weather pattern looks to return for next week with potentially a broad trough moving across the area. However, there is still some spread in the timing of the arrival of the next round of precipitation. Cluster analysis of ensemble solutions show 55% of members going with a faster solution which has precipitation arriving as early as Sunday while 45% of members are slower, with precipitation arriving closer to Monday or even later.

REST OF UTAH AND SOUTHWEST WYOMING

VFR conditions are expected to prevail across the area under increasing low level cloud cover through the overnight hours. Light northerly flows are expected across the western portion of Utah through the overnight, with other areas expected to return to diurnal flows. An area of isolated to scattered precipitation is expected to push into northern Utah/ southwest Wyoming early Tuesday morning. The biggest impact from these area showers will be lower of CIGs that may obscure higher terrain features.

SLC WATCHES/WARNINGS/ADVISORIES

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