Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
490 FXUS65 KSLC 172132 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 332 PM MDT Sun Aug 17 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. && .SHORT TERM (Through 12Z/6AM Tuesday)...A general southwesterly flow aloft remains across the Great Basin region this afternoon, upstream from a broad upper ridge encompassing the Southern PLains. A weak vorticity maxima embedded within this southwesterly flow is noted in water vapor imagery lifting through northern Utah, and helping to induce isolated terrain-driven convection over northern Utah. Any lingering activity will quickly dissipate this evening as this feature lifts away from the area, and daytime heating wanes. Elsewhere drier air has overspread central and southern Utah this afternoon which is allowing for little more than modest cumulus development over the terrain. The Southern Plains ridge will retrograde over the next 24 hours as it becomes established near the Four Corners region by late Monday. Rising heights across the forecast area coupled with a much drier airmass advecting up from the southern Great Basin will result in a continued warming and drying trend under mostly sunny skies. This warming trend will push max temps 2-4 degrees above climo Monday afternoon. .LONG TERM (After 12Z/6AM Tuesday), Issued 331 AM...As high pressure establishes near the 4-Corners region over the next several days, hotter, drier conditions are expected. Temperatures will approach the century mark along the Wasatch Front by Tuesday. Some impact to those who are heat sensitive and/or lack adequate cooling will increase in likelihood by this time across valley locations of Utah...and this increased HeatRisk will extend through at least Wednesday. Current levels do not suggest a need for headlines yet...but this will need to be monitored. As moisture begins to advect around the ridge into western Utah Wednesday, convection will begin to increase in coverage across southern Utah. This moisture will spread east with time, with more a more widespread threat of thunderstorms by Thursday. The majority of the ensemble members suggest this monsoon surge will deepen...and may extend into early next week. && .AVIATION...KSLC...Nearby showers will likely diminish by 23-00z, with quieter conditions expected overnight. Southerly winds are likely to prevail, however there is still a 20% chance winds shift northwesterly between 00-03z. VFR conditions will prevail. .REST OF UTAH AND SOUTHWEST WYOMING...Isolated showers/thunderstorms across higher terrain of N-UT and SW-WY will likely diminish by 00- 01z, with quieter conditions expected overnight with terrain-driven winds. Winds could still be gusty and erratic near showers through 01z. VFR conditions will prevail. && .FIRE WEATHER...Lingering moisture across northern Utah will maintain isolated high based showers and dry thunderstorms through early this evening, mainly near the Idaho border region. Gusty outflow winds in excess of 40 mph and occasional lightning with little if any measurable rainfall can be expected with these storms. Otherwise drier air has spread across central and southern Utah, where gusty south winds combined with RH near 15 percent will result in elevated fire weather conditions through early evening. High pressure will strengthen near the Four Corners region during the early portion of the week resulting in a warming and drying trend through Tuesday. High temperatures will run several degrees above normal by Tuesday as the they approach daily records. Meanwhile RH will fall into the single digits across most valley locations Monday, with marginal to poor overnight RH recovery Monday night. This high pressure centered near the Four Corners will help pull monsoon moisture northward into the region during the middle to latter portion of the week. Initially this moisture will remain elevated as it spreads across much of Utah by Wednesday, resulting in a few high based showers and dry thunderstorms. As the week progresses, moisture will continue to spread into the region resulting in a better chance for showers and thunderstorms capable of producing wetting rain beginning Thursday, and continuing through next weekend. With this increase in moisture, RH values will trend higher while daytime temperatures trend cooler for the latter half of the week. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ Seaman/Kruse/Cunningham For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity