Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
495 FXUS65 KSLC 162059 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 259 PM MDT Tue Jul 16 2024 .SYNOPSIS...High pressure will further build across the region through late week. Daily showers/storms will remain a potential each afternoon/evening, with coverage of these greatest across the central/southern mountains. The threat of heat- related illness may increase across the lower elevations of southern Utah by next weekend. && .SHORT TERM (Through 12z Thursday)...Elongated high pressure centered over New Mexico at this time will gradually shift east over the four corners region over the next 48 hours. As this occurs slightly deeper moisture along the western periphery of the center of circulation will trend to nose into far southwestern Utah beginning tomorrow allowing a slight uptick of PWAT across that region. Latest WPC excessive rainfall outlook does include a sliver of southwestern Utah in the "marginal" category, but in large storms will remain quite pulsey and of short duration maintaining "possible" flash flood potential across our canyon country, but only isolated in nature. A key factor to maintain this is lack of instability (on the order of 250-500 J/KG at its peak), and minimal shear for maintenance of updrafts and net duration of any heavy rainfall. Outside of the above, minimal sensible weather changes are anticipated vs. the last few days (during the short term period). .LONG TERM (After 12z Thursday), Issued 259 AM MDT... High pressure will persist through the long-term period as the ridge overhead slowly shifts westward. While daily thunderstorms and high-based convection will continue through Day 7 across southern UT and higher terrain, Thursday and Friday will feature a higher amount of moisture across the area, expanding those thunderstorm chances further north across nearly the entire forecast area. With low levels remaining fairly dry, gusty outflow winds will be the main threat, with flash flooding also possible with any training storms...especially across the south. As northerly flow develops as the ridge shifts west, this will allow drier air to filter in across the area beginning Saturday, limiting precipitation chances across the north. Maximum temperatures will linger just above normal, largely unchanged. One area to watch out for regarding heat would be Lower Washington County, which may struggle with overnight relief as minimum temperatures hover around 80F. This is highlighting a Moderate to Major (Orange to Red) HeatRisk for the St. George metro, suggesting a risk of heat-related impacts. && .AVIATION...KSLC...VFR conditions will persist for the KSLC terminal through the period. Skies will be mostly clear with intermittent cumulus. Afternoon convective potential is very low (5%). Winds will be diurnally drive with a northerly lake breeze transitioning to a southerly drainage breeze after sunset. .REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will persist across the airspace throughout the period. Afternoon convection will mainly be confined to central and southern Utah. Weak instability and modest moisture profiles will limit the strength of storms, but gusty outflow 30-45 kts will be possible near convective activity. Otherwise, winds will be light and variable with convection diminishing this evening. && .FIRE WEATHER...Noting another round of scattered shower/storm development focused over the southern mountains this afternoon, though storms are not particularly strong, and associated rainfall reaching wetting rain levels have been spotty at best. Just enough moisture exists at the lower levels to limit any associated gusty outflows to peak in the 30 mph range, similar to yesterday`s development. Both these trends will be maintained moving forward into the mid/late week period with sensible weather changes remaining largely minimal outside of slight uptick of wetting rain potential across the southwestern mountains beginning tomorrow. At this time, not seeing significant changes to weather trends into next week. Winds associated with the high pressure are anticipated to remain on the light side (outside of modest outflow potential associated with storm passages), and largely diurnally driven within the terrain. Daily storm development will remain a potential each day in the terrain, but looks to remain pulsey and rather short lived over any one area allowing dry conditions to prevail. Foresee not much more than spotty wetting rain potential each day, most likely across the central/southern mountains. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ Merrill/Mahan/Cunningham For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity