


Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
735 FXUS65 KSLC 181015 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 415 AM MDT Sat Oct 18 2025 .SYNOPSIS...A drying and warming trend is expected through Sunday before a cold front passes through northern/ western Utah and southwest Wyoming Sunday night through Monday morning. Another area of low pressure moves through central/ southern Utah mid-week with high pressure building thereafter. && .SHORT TERM (Through 12Z/6AM Tuesday)...A relatively cool post- frontal northwesterly flow will remain in place across the northern half of the CWA through today while the southern half of the area gradually warms as we begin the transition to a south to southwesterly flow. Dry conditions are expected across the area through the daylight hours with high temperatures expected to be near to slightly below normal. Through Sunday, flow will increase out of the southwest ahead of the next trough that is set to graze the forecast area Sunday night through Monday morning. A notable period of relatively strong warm air advection will spread over Utah and southwest Wyoming, allowing high temperatures to climb back to above-normal levels across much of the area. In addition to the late season warmth, breezy southwesterly winds are expected during the afternoon hours with the strongest winds anticipated west of the I-15 corridor. At this time, there is a near zero percent chance that these winds will become strong enough to warrant headlines. However, afternoon wind gusts will peak between 20-30 mph across the aforementioned area. Sunday night, the grazing trough will begin passing through the northern area, draping a cold frontal boundary into Utah and southwest Wyoming. Current model guidance is supportive of this cold front progressing through northern Utah and southwest Wyoming Sunday night through early Monday morning, brining isolated to widely scattered snow showers across the far northern mountains and light rainfall to the far northern valleys (i.e. Cache, Bear River, and Ogden Valley). Little to no impact is expected with these showers, however, there is about a 10% chance that we will see upwards of 1 inch of snow near the high point of US-89 through Logan Canyon. The cold front will continue its track through the western Utah valleys through the early morning hours on Monday, likely not carrying enough momentum to reach lower Washington County and/ or the lower elevation valleys of eastern Utah. For the areas that do see the frontal boundary (western/ northern valley areas), expect temperatures to fall back below normal for Monday alongside dry conditions. The biggest impact to note in the wake of this cold front will be the potentially freezing temperatures on Tuesday morning for areas in the far northern Utah valleys, as well as the Uinta Basin. .LONG TERM (After 12Z/6AM Tuesday)...The long-term period will be relatively quiet, with low precipitation chances and temperatures sitting around normal for this time of year. The coolest temperatures of the long-term are expected on Tuesday morning, though active agriculture areas will likely remain above freezing. After a brief period of high pressure on Tuesday, a closed low moving in from the southwest will pass across southern Utah/northern Arizona on Wednesday afternoon and evening, bringing isolated to scattered showers to mostly southern/eastern Utah. While there is still some decent spread in QPF, most locations will see less than 0.10-0.25" given an overall lack of moisture...though the NBM 90th percentile suggests up to 0.50" in the southern mountains is possible. Snow levels, while dipping slightly with the passage of the wave, will still likely remain above 9500ft. High pressure will then rebuild across the region, with near-normal high temperatures in the upper-60s along the Wasatch Front and most other lower elevation valleys. In other words, a beautiful few days! However, this dry spell will not last long, as model guidance is pretty honed in on a broad longwave trough entering the western US next weekend. && .AVIATION...KSLC...Diurnally-driven winds will continue, with southeasterly flow transitioning to northwesterly around 17-18z. VFR conditions will prevail with mostly clear skies. .REST OF UTAH AND SOUTHWEST WYOMING...Winds will remain largely light and terrain-driven with VFR conditions and mostly clear skies prevailing. The one exception is any fog development around 12-15z, particularly near KLGU and KHCR, though this chance is low (<20%). && .FIRE WEATHER...A dry and stable northwesterly flow will begin to shift toward a more west to southwesterly flow over the next 24-36 hours, promoting deeper mixing and a more unstable low-level environment. Through Saturday, temperatures will warm ever so slightly as the previous cold airmass continues to depart the region, with warmer west to southwest flow spreading into the region late in the day. Daytime highs are expected to run right around normal for this time of year alongside increasingly dry relatively humidity values. Afternoon minimum RH will drop by 5 to 15 percent as compared to Friday, with the most aggressive drying trend being noted across far northern Utah. For the lower lying valley areas of southern Utah, values are anticipated to drop back into the 20 to 25 percent range. A stout warming and drying trend is expected to continue into Sunday as dry south to southwest flow spreads across much of Utah ahead of the next low pressure system. Afternoon humidity will trend downward by another 5-10 percent alongside increasingly gusty afternoon winds. Of note, west-central to southwest Utah are the two main areas of concern for elevated to near-critical fire weather conditions as humidity will fall into the 15 to 20 percent range alongside peak gusts between 20 to 30 mph. The strongest winds, however, will be confined to the far northern Utah mountains where gusts will likely exceed 35 mph in some of the higher exposure terrain. That said, humidity in this area will only bottom out around 30 to 40 percent. The aforementioned cold front will progress through the northern area Sunday night into Monday morning, bringing a shift in wind direction to the north to northwest. The front itself is currently anticipated to progress through the western valleys of Utah through early Monday, bringing a similar wind shift and cooling trend. Only the northern mountains (Salt Lake County northward) will see a shot of light precipitation with low end probabilities of wetting rains (10 to 30 percent). Stable conditions build in the wake of this cold front through at least the middle of next week. Around Wednesday, another low pressure system will move in from the south, helping to bring a round of light precipitation to the central and southern mountains, as well as maintaining cooler temperatures across the state. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ SHORT TERM...Webber LONG TERM...Cunningham AVIATION...Cunningham FIRE WEATHER...Webber For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity