Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
738 FXUS65 KSLC 252117 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 317 PM MDT Sat May 25 2024 .SYNOPSIS...High pressure will gradually work its way into the area through the first half of the coming week, resulting in warmer and drier conditions. && .SHORT TERM (THROUGH 12Z MONDAY)...A shortwave trough currently over Utah will continue to translate east out of the area this evening. An associated cold front currently extends across southwest through east-central Utah and will weaken before reaching far southern Utah this evening. Convection that developed today near the boundary has brought locally moderate rain (snow above around 8-9 kft), small hail, gusty winds, and even a funnel cloud that was reported near Delta. Scattered convection will continue into this evening before tapering off from west to east. Behind the exiting trough, high pressure will gradually build into the area over the next few days. This pattern will bring warmer and drier conditions to the area tomorrow. Afternoon maxes will warm around 6-12 degrees for tomorrow compared to today, though that would still translate to slightly below climatological normals. .LONG TERM (After 12Z/6AM Monday), Issued 338 AM MDT... A sharp warmup will be underway on Memorial Day across Utah and SW Wyoming as a transient, albeit strengthening mid-level ridge axis will traverse eastward across the region. When compared to today (Saturday), expect a very noticeable nearly a 20F warmup on Monday across northern and central Utah, with about a 10F warmup across southern Utah. NBM probability of 90F at SLC has climbed to 38%, now centered on Wednesday. The mean first 90F day in SLC is June 8, so we`re not too far off the mark should 90F be reached. A well-clustered model consensus with high forecast confidence early in the week then begins to wane as the above-mentioned ridge axis exits to the east by Tuesday-Wednesday, with increasing deep-layer SW flow developing on Tuesday as an area of low pressure moves into coastal British Columbia. As this evolution transpires, additional warming will be in store for Tuesday, with temperatures reaching the mid to upper 80s across the Wastach Front, and the upper 90s across Lower Washington County. We can`t rule out an isolated shower or thunderstorm by Tuesday afternoon, mainly over northern Utah and SW Wyoming. Similar to yesterday`s forecast, uncertainty begins to emerge by midweek, with the greatest source of uncertainty regarding the track, strength and timing of the aforementioned low. We now see a clearer signal for the emergence of two forecast scenarios appearing by Wednesday and carrying us through early next weekend, and those two scenarios are a ridge vs a trough scenario, with a slight (about 60% of the solution space) nudge towards the trough scenario. Should the ridge remain in place, warm, mainly dry conditions would be the most likely outcome through the remainder of the forecast period. The trough solution would bring a mid to late week reduction in temperatures back closer to average (or even below average in the stronger trough solutions) with periods of showers across northern Utah and SW Wyoming as well as gusty winds on the periphery of the trough. Given the uncertainty and the nearly equally divided model solution space, it`s too early to pick a ridge or trough solution as a most likely outcome. It is worth mentioning that models are trending very gradually towards the trough idea, and this is supported by the most recent runs of deterministic, global models as well. Finally, this trend is also reflected in the official forecast which shows gradual cooling Thursday and Friday. && .AVIATION...KSLC...VFR conditions will persist for the KSLC terminal. Widespread precip has pushed east with a few lingering showers through the early evening. Skies mostly clear overnight with some light and variable mixed in with a mean southerly flow. Light southerly flow persists overnight. .REST OF UTAH AND SOUTHWEST WYOMING...Dry air will move in from west to east as storms push out of the area early this evening. This will leave VFR conditions areawide with CIGs lifting and becoming mostly clear overnight. Winds become light and variable overnight. && .FIRE WEATHER...A storm system and associated cold front will continue moving across the area through this evening, bringing scattered, generally wet, thunderstorms. Some of the stronger storms are capable of producing small hail and gusty winds. In addition, prefrontal winds will continue to be strong across far southern Utah into the early evening hours. As things wind down tonight, a drier airmass will spread into the area and remain in place for much of the coming week. Temperatures will also trend warmer tomorrow through Tuesday before a mostly dry cold front moves into the area late Wednesday through Friday. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ Cheng/ADeSmet/Mahan For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity