639 FXUS65 KSLC 292229 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 429 PM MDT Sun May 29 2022 .SYNOPSIS...A slow moving storm system will continue to bring cool and wet weather to the northern two-thirds of the area while the southern third remains dry and relatively warm. High pressure will make a return by the middle of the week, bringing warm and dry conditions to the area once again.. && .SHORT TERM (Through 12Z/6AM Tuesday)...A broad trough with a center currently noted over southern Idaho/ the north-central Great Basin region will continue to bring scattered showers and thunderstorms to the northern two-thirds of the forecast area through the remainder of the day time hours. As sun sets, a temporary decrease in coverage of showers and thunderstorms is expected, however, model guidance is consistent in producing a re-enhancement of showers overnight tonight as the mid-level cold core begins to move overhead in conjunction with modest vorticity advection. Decent 700mb flow (around 15-20kts) will remain in place during this period across northern Utah, which will help place most of the shower focus over the terrain. Period of light to moderate snowfall between midnight and 6am are likely to produce quick accumulations of snowfall above ~7500ft. Mountain passes above these elevations are likely to see areas of road slush by the morning hours, however, decent road snow accumulation is anticipated around the Bald Mountain Pass portion of Mirror Lake Highway and may create hazardous driving conditions for unequipped vehicles. As such, a Winter Weather Advisory remains in effect for the Wasatch Mountains and western Uinta Mountains through Monday evening. As the mid-level cold core lingers overhead during the day on Monday, showers are expected to continue across the northern half of Utah and southwest Wyoming through much of the day. Although a cooler airmass will be in place, snow levels will gradually rise through the afternoon hours as solar heating takes over. Less threat of thunderstorms exists on Monday as supporting shear decreases, however, a few rumbles of thunder cannot be ruled out. Isolated showers will continue over the northern Utah mountains through the late evening hours on Monday before largely tapering off through the overnight hours. One last day of showers will be in store on Tuesday before a period of ridging moves into the area. Temperature-wise, daytime highs will run ~10-15 degrees below average across the southern half of Utah and ~15-20 degrees below average across the northern half of Utah and southwest Wyoming as a result of the colder airmass settling into place. Tonight, hard freeze conditions are expected for the high elevation Sevier River Valleys, particularly around the Panguitch area. A hard freeze warning will go into effect at 9PM MDT and continue through 9AM, where temperatures are then expected to be above freezing. These hard freeze conditions will be possible once again in the upper Sevier River Valleys on Tuesday morning, in addition to portions of the Wasatch Back (specifically the Park City, Oakley, Kamas, and Heber City areas). No headlines have been made at this time. .LONG TERM (After 12Z/6AM Tuesday)...The last closed low associated with the multi-day broad trough over the Intermountain West is expected to slide through the northern Great Basin by Tuesday afternoon. The low will be filling as it moves into our area, but will provide additional synoptic support for another round of showers and thunderstorms, primarily in the afternoon hours and north of an approximately Delta to Price line. Elevated winds are expected over southern Utah yet again, though not as significant as in recent days. Temperatures will start to rebound but look to remain 5-15 degrees below normal. Looking ahead to the remainder of next work week, a West Coast ridge will translate inland through at least Friday, bringing a notable warming trend and generally quiet weather conditions. The Wasatch Front will again reach into at least the mid 80, with upper 90s for the lower elevations of Washington County. HeatRisk looks to remain generally in the yellow category (dangerous for only the most sensitive groups), though with a few spots in vicinity of Lake Powell reaching orange (dangerous for those who are sensitive to heat). By late in the week, another longwave trough sets up near the West Coast, with our area being generally downstream. Ensemble members generally favor a slow progression, with uncertainty in whether the trough axis translates as far inland as the Great Basin. Regardless, a few weak leading shortwave troughs are possible, and given the time of year there would be a threat of microbursts/thunderstorms with any such disturbances (from Friday through early the next week). Looking at the WPC cluster analysis, the EPS generally favors a filling trough with an axis that doesn't quite reach us through at least Sunday, while the GEFS has more membership favoring a trough axis reaching us. Either way, the consensus solution is a minor cooling trend by next weekend and some convective precipitation chances. && .AVIATION...KSLC...VFR conditions will be mixed with occasional MVFR conditions as storms threaten the KSLC terminal throughout the entire period. CIGs will remain below 6kft creating mountain obscuration. Storms will be scattered throughout the afternoon/early evening with the threat of small hail, lightning, and gusty/erratic winds. Rain becomes more widespread overnight along with less of the aforementioned threats. Westerly crosswinds associated with storm outflow will remain a threat as storms impact the terminal. Similar conditions tomorrow with scattered rain/thunderstorm develop throughout the afternoon. .REST OF UTAH AND SOUTHWEST WYOMING...Scattered storms over the northern terminals will create intermittent MVFR/IFR conditions, but VFR conditions will dominate as CIGs remain ~5-7kft creating mountain obscuration. Isolated storms will contain small hail, lightning, and erratic wind gusts. Overnight rain becomes more widespread, but aforementioned storm threats will decrease. Similar conditions tomorrow with scattered rain/thunderstorm develop throughout the afternoon. KCDC, KSGU, and KBCE will remain VFR with little to no threat of rain or lowered CIGs. && .FIRE WEATHER...A storm system pushing through the area will continue to bring wet, winter-like weather across the northern two-thirds of Utah today and tomorrow with critical fire weather conditions across the southern third of Utah during the same time. Far southern Utah will experience solid critical fire weather conditions through the remainder of the day today, warranting a continuation of the existing Red Flag Warnings in Utah's Mojave and the Grand Staircase area through 10PM MDT. A cooler and more moist airmass will remain draped across the area during the day tomorrow, allowing humidities across the northern half of Utah to remain fairly high. However, very minimal change in afternoon minimum humidities are expected across the southern half of Utah. With breezy conditions still expected during the day across southern Utah, isolated critical fire weather conditions will be possible. Cooler and wetter weather remain forecast for the northern half of Utah through Tuesday afternoon as the storm system begins to lift out the area. By Wednesday, substantial warming is expected across much of the area as a ridge of high pressure begins to build into the area and brings more stable conditions to the eastern Great Basin. An offshore trough is projected to develop during the latter half of the week and could generate another period of critical fire weather conditions across portions of Utah as winds ramp up in a warm and dry environment. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...Red Flag Warning until 10 PM MDT this evening for UTZ497-498. Hard Freeze Warning from 9 PM this evening to 9 AM MDT Monday for UTZ126. Winter Weather Advisory until 6 PM MDT Monday for UTZ110>112. WY...None. && $$ SHORT TERM...Webber LONG TERM...Van Cleave AVIATION...Mahan FIRE WEATHER...Webber For more information from NOAA's National Weather Service visit... http://weather.gov/saltlakecity For frequently asked questions about the Area Forecast Discussion visit... http://weather.gov/saltlakecity/general/afd_faqs.php