Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
369 FXUS65 KSLC 162059 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 259 PM MDT Thu May 16 2024 .SYNOPSIS...An active, unsettled pattern will continue through at least midweek next week. && .SHORT TERM (Through 12Z Saturday)...It`s a warm, summer-like day across much of the region, with temperatures averaging around 5 degrees or so above normal for the date. Today will likely be a brief pause in an otherwise active pattern that will extend through the entire long term forecast period. Spring`s not done with Utah yet! Afternoon upper air and satellite analysis indicates broad upper level ridging across the eastern Pacific. A relatively strong upper level jet is present across the Pacific Northwest with a compact but relatively strong shortwave trough crossing near the Washington/British Columbia border. This shortwave trough will remain well north of the area...but push a mainly dry cold front into northern Utah Friday morning. CAMS suggest the potential for an area of relatively high-based convection is possible near and ahead of this front across portions of northern and eventually central Utah Friday afternoon and evening. Given inverted-v type profiles, expect the main threat will be gusty, microburst winds near any high-based showers and thunderstorms. Gusty northwesterly winds will be possible behind the front, though remaining well below advisory criteria. The strongest winds are likely in Uinta County, WY, particularly eastern portions of the county closer to the parent shortwave trough. Any convection will end near sunset Friday evening. .LONG TERM (After 12Z Saturday)...We will pivot to a more active pattern for the long-term period, bringing overall cooler and somewhat wetter weather to the forecast area. Starting on Saturday, a weak warm front-like feature will push northward from its position over central Utah, producing isolated to scattered showers from Saturday afternoon through Sunday morning. Expect a 10-20% chance of thunderstorms over higher terrain, particularly during the afternoon and evening. Any storms that do develop could produce gusty outflow winds given dry low- levels and decent mid-level lapse rates, but overall the risk is low. By mid-day Sunday, a longwave trough will begin to push into northern UT from the PacNW. However, there is still some uncertainty among model guidance regarding its southern extent as it moves into our area. Ensembles are trending towards a more amplified, slower solution (roughly...70% chance), which is also what deterministic models suggest. In terms of sensible weather, temperatures would cool by 5-15 degrees and would cool further south. We would also see precipitation reaching further south, however given limited moisture, QPF will still remain fairly low (<0.1" in all valleys and <0.25" across all mountains). Keep in mind that there are still members that favor a shallow trough that quickly ejects eastwards...which would likely limit the cooldown to only 5 degrees or so. After a shortwave ridge late Tuesday and Wednesday with a brief but strong warming trend, another longwave trough is looking more likely to develop heading into Thursday. Details are unclear at this point, however 60% of ensemble members favor a more dynamically impressive system with stronger cold-air advection. && .AVIATION...KSLC...VFR conditions will persist with high based clouds or SKC conditions. Light northwest winds are forecast to shift southeasterly this evening. An increase in northwest winds are forecast tomorrow morning. .Rest of Utah and Southwest Wyoming...High based clouds and light winds are forecast to prevail through the remainder of the evening and overnight hours. VFR conditions are thusly forecast. An increase in winds are forecast headed into late tomorrow morning and afternoon. && .FIRE WEATHER...A trough embedded in the northern jet stream will bring a weak cold front through northern and central Utah Friday. Isolated, high-based showers and thunderstorms will be possible near this front. Gusty and erratic winds will be likely near this convection. On Saturday, the remnant front will begin to lift northward, with increased areal coverage of mainly high- based showers and thunderstorms roughly between I-80 and I-70. By Sunday, yet another trough will shift the threat of convection into northern Utah. Dry and breezy conditions are expected for southern Utah through Sunday. The active pattern continues into the next week with additional quick moving systems impacting the region. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ Kruse/Cunningham/NDeSmet For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity