textproduct: Salt Lake City

KEY MESSAGES

- Accumulating mountain snow is expected across all Utah mountains through Monday morning. Upwards of 12" of snow is expected above 9000 feet, and 3-6" of snow down to around 7000 feet. Upper elevations of the Cottonwoods and western Uintas may see localized accumulations 18-24".

- Cool, dry, and stable conditions build in Tuesday following the passage of this system.

- A weak system looks to impact the region Wednesday/Thursday ushering in a brief period of low elevation rainfall and high elevation snowfall across primarily northern and central Utah.

DISCUSSION

Currently, a mid-level trough is traversing across the Great Basin with its axis nearly centered along the UT/NV border. With this trough, a cold front continues to sweep across much of UT, having already traversed the western half of the state. While the lower levels are slowly drying out, weak ascent with modest moisture aloft will result in light to occasionally moderate rainfall persisting across much of the forecast area through roughly 09z. From 09z on, higher terrain will be favored for precipitation given drier low levels of the atmosphere. As such, the flood watch will be allowed to expire at 06z for southern UT and portions of central UT.

700mb temperatures will continue to cool following the passage of the cold front to roughly -3C to -4C resulting in snow levels continuing to drop through the evening to around 6500ft. Additionally, northwest flow aloft will persist, resulting in a favorable pattern for widespread mountain snow across much of Utah's high terrain. Of note, a TROWAL feature has been identified via satellite imagery serving to wrap more moisture around the northwest side of a deepening upper low located over northern UT. This has resulted in another round of widespread light to moderate rain observed across northern UT, and will also contribute to snowfall totals across our northern UT mountains. Across our UT high terrain (generally 9000ft or greater), 3-6" of additional snowfall is expected. Some areas, such as the Upper Cottonwoods and Western Uintas may see additional snowfall totals from 6-12" given favorable northwest flow orientation overnight.

Transient ridging builds in Monday in the wake of the deepening trough as it progresses east. This will result in most precipitation coming to a halt across the forecast area, though some lingering showers across the UT high terrain may persist. This feature is forecast to persist through Tuesday bringing quiescent conditions and unseasonably cool temperatures, potentially as low a 15F below seasonal normals areawide.

Ensemble guidance has come into better agreement with a weak mid- level trough sweeping through the Great Basin on Wednesday. This system is not expected to bring a whole lot of moisture with it, and with weak forcing, only light valley rainfall with light mountain snow accumulations are expected across northern and central UT. Following this system, dry conditions develop once again as ridging becomes dominant across much of the western U.S. through the remainder of the week and into the weekend.

AVIATION

KSLC...MVFR to low-end VFR conditions within periods of rain will persist through the overnight hours. There is a 30% chance of IFR CIGS/VIS at times within heavier precipitation. Rainfall will taper off late tonight with a return to VFR conditions by 15Z Monday. Winds will remain northwesterly through the TAF period.

REST OF UTAH AND SOUTHWEST WYOMING...Periods of rain will persist across northern Utah and southwest Wyoming through tonight resulting in MVFR to locally IFR conditions. Conditions will improve to VFR Monday morning. Across southern Utah, CIGS may temporarily fall in the MVFR range at KCDC overnight with passing showers, otherwise VFR conditions will prevail.

SLC WATCHES/WARNINGS/ADVISORIES

UT...Winter Weather Advisory until 11 AM MST Monday for UTZ111-112.

WY...None.