Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
495 FXUS65 KSLC 081001 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 401 AM MDT Sat Jun 8 2024 .SYNOPSIS...High pressure will build into the area today before another weak disturbance grazes northern Utah late tomorrow into Monday. Lingering moisture will maintain showers and thunderstorms across portions of the area into Monday before drier air spreads into the area. && .SHORT TERM (THROUGH 12Z MONDAY)...The shortwave trough that brought the showers and thunderstorms yesterday is now exiting east into Wyoming, with what`s left of the showers continuing to diminish. High pressure building into the area today will bring a more subsident airmass, but daytime heating is expected to result in enough instability to fire up isolated to scattered showers and thunderstorms this afternoon given lingering moisture. While PWATs are forecast to be lower compared to yesterday, the forecast of ~0.65-0.9 inches across northern and central Utah should be sufficient to support those showers, although precipitation amounts should be a bit less. Temperatures will remain on the hot side, though some sites will trend slightly cooler compared to yesterday. For the lower valleys of far southern Utah, an Excessive Heat Warning remains in effect through this evening. Although HeatRisk guidance has lowered, there are still some localized areas in these zones which are being highlighted by the guidance. The ridge will quickly shift east of the area by tomorrow afternoon as the next trough enters the West Coast states, grazing northern Utah late tomorrow into Monday morning. Southerly flow will increase ahead of this trough, and expect to see showers and thunderstorms to develop again. With drier air working into west-central and southwest Utah, showers and thunderstorms on Sunday will likely be focused near the Idaho border, across the northern and central mountains, and adjacent valleys to their east. Given better dynamic support, some of these thunderstorms will trend stronger again, particularly near the Idaho border, with wind and small hail being potential threats. Otherwise, temperatures will trend warmer again across the north while cooling across the south. .LONG TERM (After 12Z/6AM Monday)...A shortwave will be traversing the Intermountain West on Monday. Given modest mid level moisture expect diurnal convection to develop during the afternoon. Convective parameters suggest mainly general thunderstorms with some gusty erratic outflow winds possible. The greatest probability (~30% chance) for convection will be across the terrain of eastern Utah given a majority of guidance has the shortwave axis moving through the western half of Utah early in the day. Temperatures on Monday will be relatively "cool" compared to the following days as high temperatures will be ~5 degrees above normal. As this shortwave exits, high pressure starts to re-establish itself over the region. This will result in mostly dry conditions and clear skies dominating with temperatures increasing 10-15 degrees above normal by midweek. This translates to mid to upper 90s for most valley locations with mid 100s across far southern Utah. These hot temperatures will be tapered by the end of next week as a cutoff low off the coast of southern California moves onshore and helps to lower heights across the area. However, temperatures will remain ~5 degrees above normal. 31% of guidance has a slower progression of this low likely delaying its impacts by a day or so. Regardless, all members do have this low moving through some time late in the week. Southerly flow will increase ahead of the low which will increase afternoon surface winds. Moisture will gradually increase as well as this low moves onshore with afternoon convection increasing. Guidance has the center of this low moving across northern Arizona so precipitation chances will be higher further south. && .AVIATION...KSLC...VFR conditions will persist for the KSLC terminal as conditions remain mostly dry with a few high clouds. A stray thunderstorm is possible during the afternoon, but most convective activity will remain well to the west of the terminal. A light southerly wind will transition to a light northerly wind during the afternoon. .REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will persist for the airspace throughout the period. Afternoon convection is expected across central Utah with mainly dry conditions for southern and northern Utah. Winds will be light and variable. && .FIRE WEATHER...Moisture will linger across the area today while high pressure builds back into Utah. Expect generally isolated to scattered showers and thunderstorms today. Showers will in general be weaker than yesterday with a lower potential for wetting rain. Gusty outflow winds will continue to be a threat with some of the showers and thunderstorms. Tomorrow, another weak weather disturbance will graze northern Utah. This will bring the threat of somewhat stronger showers and thunderstorms with slightly higher potential for wetting rain. Additionally, southwest winds will increase across southern Utah, bringing marginal Red Flag conditions. High pressure will then return to the area through midweek, accompanied by a drying trend. Temperatures for the most part will remain hot for this time of year. The next potential storm looks to arrive late Thursday through Friday. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...Excessive Heat Warning until midnight MDT Saturday night for UTZ123-124-131. WY...None. && $$ Cheng/Mahan For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity