Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
476 FXUS65 KSLC 262108 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 308 PM MDT Sun May 26 2024 .SYNOPSIS...High pressure will continue to work its way into the area through the first half of the week. A substantial warming and drying trend will accompany this high, pushing temperatures 5 to 10 degrees above normal by Tuesday. A mostly dry cold front will push through the region late Wednesday through Thursday. && .SHORT TERM (THROUGH 12Z TUESDAY)...High pressure continues to build into Utah from the west this afternoon, with dry and stable conditions today. Scattered shallow cumulus noted across the area today should dissipate this evening. Otherwise, temperatures have trended upward for today and will continue doing so tomorrow. Afternoon max temperatures tomorrow will rise a further 5-10 degrees compared to today, resulting in slightly above-normal values. The NBM has a 71% chance for SLC to reach 80F tomorrow. Midlevel moisture will increase across the area tomorrow, especially across central Utah, ahead of the next upstream trough. This, combined with greater instability (HREF ensemble mean SBCAPE up to 250 J/kg over the higher terrain), would bring a potential for some high-based convection tomorrow afternoon. This idea is supported by a consensus of a combination of model H5 RH blowups and simulated reflectivities greater than 20 dBZ. While there is a low chance for measurable rain, some isolated gusty microburst winds will be possible. .LONG TERM (After 12Z/6AM Tuesday), Issued 405 AM MDT... On Tuesday, deterministic and ensemble model solutions are well- clustered in their respective output, all showing the presence of modest deep-layer southwest flow across the region in the wake of a departing ridge, and downstream of an area of low pressure approaching the British Colombian coastline. Such a configuration is favorable for warm temperatures across the region, and that is indeed expected to be the case, with the warmest day of the year so far in store for Tuesday. Highs will surge into the upper 90s across Lower Washington County, and into the mid to upper 80s across the Wasatch Front. Modest moisture advection will combine with the influence of the approaching low to promote an isolated shower or thunderstorm or two, mainly across high terrain areas of northern Utah and SW Wyoming during the afternoon and early evening. Gusty microburst winds appear to be the main threat. Over the past several days worth of forecasts, the greatest source of uncertainty has been around the strength, track and timing evolution of the British Colombian low. While there still remain some lingering differences, model solution space appears to be converging on a solution that drops this low across the Northern Rockies in the Wednesday to Thursday timeframe, with the most likely solution suggesting the low and associated cold front will graze northern Utah and SW Wyoming in the process. There is a seasonably strong tight height and baroclinic zone associated with this low, so main impacts with it appear to be gusty westerly winds, especially on Wednesday and Thursday, when wind-prone locations such as SW Wyoming are in line for gusts in the 30-40 mph range during the afternoon and early evening hours. Additionally, a few showers and thunderstorms will once again develop, namely over higher terrain areas of northern Utah and SW Wyoming once again. After another warm day on Wednesday, temperatures will cool a few degrees in the wake of the front across northern areas Thursday and Friday. The above represents the current most likely solution. It`s worth mentioning that there remain some members that do not budge the ridge all all, and such an outcome would imply a continuation of warm and dry conditions through the week. Meanwhile, other members on the opposite end of the distribution drop a stronger low across Utah, suggesting greater coverage of cooler, unsettled conditions. Nonetheless, there is quite good consensus in the idea of a ridge building back across the area next weekend, with some modest strength and positioning differences. && .AVIATION...KSLC...No significant weather expected. Aside from a few diurnal cumulus, skies remain clear to mostly clear. NW winds through Sunday anticipated to shift SE between ~03-05Z Monday, with subsequent diurnal shift back NW by ~15-17Z thereafter. Some brief light and variable conditions possible near times of wind switches. .REST OF UTAH AND SOUTHWEST WYOMING...Generally benign conditions with no significant weather expected through the TAF period. VFR conditions persist with skies largely clear to mostly clear. Some modest wind gusts possible during the day at more exposed and typically gusty terminals, but otherwise anticipate fairly light winds with diurnally normal direction changes. && .FIRE WEATHER...High pressure will continue building into the area into Tuesday, maintaining a warming trend across the area. A slight increase in midlevel moisture tomorrow along with some instability may bring some weak high-based convection especially across central Utah tomorrow. Main threat would be some gusty outflow winds with little or no measurable rain. As the next trough slowly approaches the area, midlevel moisture continues to increase into northern Utah on Tuesday. Then, the cold front associated with the trough will push into northern and central Utah on Wednesday. This will bring an increasing threat of showers to northern Utah Tuesday through Wednesday. Behind the cold front, cooler temperatures will spread into the area through late week, but significant moisture is not expected. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ Cheng/ADeSmet/Warthen For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity