Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
498 FXUS65 KSLC 220921 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 321 AM MDT Tue Apr 22 2025 .SYNOPSIS...An active northern jet stream will keep the threat of periodic precipitation across northern and central Utah through much of the next week. Areas south of a line from roughly Delta to Price will largely remain dry through the next seven days. && .SHORT TERM (Through 12Z Thursday)...An active spring pattern continues through the short term forecast period. The next shortwave trough will continue to shift into the Pacific Northwest today, inducing increasing southwest flow across the Great Basin. CAMS suggest enough instability will exist across portions of eastern Nevada to generate at least isolated to widely scattered convection moving into the Great Salt Lake Desert after 00Z this evening. Additional high-based convection will be possible across west central Utah. For the last several runs of most of the CAM guidance, an area of high-based convection is forecast to cross the Wasatch Front between 03Z and 12Z Wednesday as the shortwave trough approaches the Utah border...lending more synoptic support. Outside of light precipitation (less than 0.05"), gusty and erratic microburst winds are possible, especially prior to 06Z. A weak boundary will likely shift into northern Utah by the end of the short term forecast period. As far as temperatures...expect temperatures around 5-10 degrees above normal for the date across much of the CWA Tuesday and Wednesday. .LONG TERM (After 12Z Thursday)...A weak upper trough will begin lifting north Thursday morning as transient ridging builds in across Utah and southwest Wyoming ahead of an approaching trough to our West. An active period of weather appears on tap for the forecast area as this trough appears to be quite diffluent. This will yield least some chance for showers across the state each day within the extended forecast, particularly across northern Utah, higher elevations of central Utah, and southwest Wyoming. The aforementioned trough is forecast to move quite slow as it progresses east, and there is still some uncertainty with respect to northern extent as it pushes inland and if it will close off and become an upper closed low. Around ~50% of ensemble members develop a closed upper low that is somewhat deeper than other members and have the system generally pushing inland somewhere along the northern California and Oregon coastlines. The other half of guidance keeps the trough as an open wave and generally less deep than the other half of guidance. For the members that keep the trough as an open wave, it appears to exit the region notably faster than the members that close off the upper low. If the closed upper low solution were to occur, temperatures within the extended forecast may trend lower with chances for showers increasing somewhat in future forecasts when a final solution appears more evident. The current thinking is that this system has generally trended slower, resulting in chances for showers each day with northern Utah and southwest Wyoming appearing favored within this pattern. This is due to moisture lingering over the area due to the system trending slower with ample forcing aloft. PoPs will remain elevated across the aforementioned areas through at least Monday when the trough is expected to lift away from the area. Additionally, a lingering system would also result in a slight cooldown across the state through Monday as cloud cover persists with a frontal boundary moving south across the state beginning Saturday night. && .AVIATION...KSLC...VFR conditions will prevail through the TAF period. Winds will generally persist out of the west-northwest throughout the period seeing an increase this evening following 21z. A slight chance for isolated high-based showers exists near the terminal tomorrow evening following 00z lasting through Wednesday morning. .REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions will prevail across all TAF sites through the period. Winds will remain light and variable through tomorrow afternoon before a diurnal uptick in winds out of the northwest kicks in, then calming down following 03z. There is a slight chance for isolated high-based showers across our northern Utah sites tomorrow evening following 00z, likely persisting into Wednesday. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ Kruse/Worster For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity