Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
189 FXUS65 KSLC 180914 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 314 AM MDT Mon Aug 18 2025 .SYNOPSIS...High pressure will bring a warming and drying trend to the region through Tuesday. A monsoon surge will begin as early as Wednesday and continue through at least next weekend. && .DISCUSSION...Early morning upper air and satellite analysis indicates broad ridging across the southern Plains, with southwest flow across the Beehive State. The ever present Pacific trough remains in place. For the short term, expect rising heights and the coincident increase in temperatures across the region. Near-record to record temperatures are possible Tuesday into Wednesday, with portions of the Wasatch Front seeing highs near 100F. HeatRisk suggests an increase in threat of heat related illness, especially for those without proper hydration or cooling. If your plans take you outdoors over the next 3-4 days, consider avoiding the heat of the day and make sure to drink plenty of water. Depending on how fast the moisture returns, heat-related headlines may be needed for lower Washington County, Zion National Park and Glen Canyon National Recreation Area, but uncertainty is too high to issue any headlines at this time. As the upper level ridge settles near the Four Corners mid-week, mid- level moisture will begin to increase from west to east Wednesday into Thursday. There are now some members of the ensemble systems that have slowed this moisture return by about 24 hours...with the mid-level moisture increasing on Thursday rather than Wednesday. Either way, as moisture deepens either Thursday or Friday, more widespread thunderstorms can be expected with increasing threats of heavy rain and localized flash flooding especially across southern Utah. PWs will remain at or above 90th percentile Friday into early next week across much of the region. Those with outdoor plans across southern Utah particularly near slot canyons, normally dry washes, slick rock areas and those near recent burn scars should monitor forecasts over the next week. && .AVIATION...KSLC...VFR conditions will persist through the TAF period. Winds will remain southerly through 23z before winds clock to northwesterly. Following this, winds will shift back to southerly around 03z. .REST OF UTAH AND SOUTHWEST WYOMING... VFR conditions will prevail across all sites. Generally diurnal wind directions are expected today. && .FIRE WEATHER...As high pressure strengthens across the region, a hotter and much drier airmass will build into the area. This will bring single digit humidities to much of the state with poor to very poor overnight recoveries through midweek. A monsoon surge will begin to increase mid-level moisture across western Utah Wednesday, spreading east with time. Initial thunderstorms on Wednesday are likely to be dry...with the threat of gusty microburst winds. By Thursday, storms will begin to transition to mix of wet and dry...fully shifting toward wet with attendant higher threat of wetting rains by Friday. This monsoon surge looks likely to continue into at least early next week. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ Kruse/Worster For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity