Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
257 FXUS65 KSLC 072110 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 310 PM MDT Sun Sep 7 2025 .SYNOPSIS...Utah and southwest Wyoming will see a drying trend through Tuesday. Winds will pick up Tuesday into Wednesday ahead of a slow moving trough that will bring cooler temperatures and increasing coverage of precipitation for the latter half of the week. && .SHORT TERM (Through 12Z/6AM Tuesday)...Zonal flow across Utah and southwest Wyoming is drawing drier air in, with satellite derived PWs primarily in the 0.5 to 0.7 inch range. Still seeing some isolated afternoon convection, focused over northern Utah and southwest Wyoming, with one storm near the Wasatch Front producing some small hail. The storms are expected to diminish by the early evening, with just some scattered clouds overnight. The airmass will continue to dry tomorrow. Though there will be isolated convection over northern Utah, this will likely be the quietest day with regard to convection. Temperatures will be near to just above seasonal normals. .LONG TERM (After 12Z/6AM Tuesday), Issued 337 AM MDT...A longwave trough axis will be positioned around the Pacific coast by Tuesday. The approaching storm system will result in more windy conditions and more shower and thunderstorm coverage as it tracks east. Southwest flow will pick up as an enhanced pressure gradient slides in upstream of the longwave trough axis Tuesday. This will bring south to southwest winds, with gusts of 20-30 mph. The strongest winds will be in southwest Wyoming and southwest Utah. Upper diffluence and shortwave energy tracking through in southwest flow will bring isolated or scattered showers and thunderstorms. These will be high-based, as conditions will be fairly dry ahead of the storm system, and capable of gusty, erratic outflow winds. The longwave trough will gradually track inland Wednesday, so similar conditions will continue. There will be slightly stronger flow and better forcing, with winds gusting in excess of 30 mph for southwest Wyoming and southwest Utah. Many other locations will have gusts range from 20-30 mph. The enhanced forcing will come with more showers and thunderstorms than Tuesday, largely again high-based with more wind than wetting rain. The trough and what ensembles are in good agreement on of a closed low will approach Utah Thursday, but southwest flow will continue. There will be gradual cold air advection, with valley highs decreasing from the mid and upper 80s Tuesday to upper 70s and low 80s Thursday, roughly 5F cooler than normal. Scattered showers and thunderstorms are likely for southwest Wyoming and much of Utah. By Thursday, showers and thunderstorms will be more capable of locally moderate to heavy rainfall, particularly for northern Utah. The storm system will track into Utah Friday, but be lifting northeast as it does. Showers and isolated thunderstorms are likely again, with the wettest conditions for far northern Utah. The coolest conditions of the week for southwest Wyoming and most of Utah will be Friday, with valley highs from the low to mid 70s in northern Utah and from the mid 70s to low 80s further south. && .AVIATION...KSLC...Winds will likely persist out of the northeast following the afternoon thunderstorm, gradually lightening and veering back to southeasterly by around 02-03z. A couple of isolated showers may develop off higher terrain before 23z, but will be much weaker. Light, southeasterly winds will persist overnight, gradually increasing during the morning hours. .REST OF UTAH AND SOUTHWEST WYOMING...Scattered showers and isolated thunderstorms will gradually decrease in coverage through the afternoon across northern Utah, likely ending by 01z. Winds will remain largely light and terrain-driven overnight, but may favor a southerly component in higher elevations removed from valley floors. && .FIRE WEATHER...Westerly flow will bring a steady drying trend across Utah through early Tuesday, though some isolated afternoon convection will persist, primarily for northern Utah. Southerly winds will pick up Tuesday into Wednesday ahead of an approaching Pacific trough that will slowly move through the area during the latter part of the week, bringing cooler temperatures and increasing coverage of showers and thunderstorms. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ SHORT TERM/FIRE WEATHER...Traphagan LONG TERM...Wilson AVIATION...Cunningham For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity