


Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
388 FXUS65 KSLC 130958 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 358 AM MDT Tue May 13 2025 .SYNOPSIS...Gusty winds redevelop across east Utah as a cold front progresses Tuesday. Cooler and unsettled conditions largely persist through the rest of the work week, with potential for another stronger and more widespread system by the upcoming weekend. && .SHORT TERM (Through 12Z/6AM Thursday)...Morning water vapor loop shows a broad trough continuing to dig southward into the Great Basin. Area observations as well as SPC mesoanalysis data show that the surface front and low level baroclinic zone associated with this trough has already progressed through much of the Wasatch Front. Moderately strong cold air advection behind the front has resulted in some maintained modest wind gusts, though comfortably below advisory criteria aside from an occasional localized gust here and there. As such, allowed the prior headlines to expire on schedule. Aside from the winds, the cold air advection behind the front is resulting in temperatures around 15F to 25F colder than at this time 24 hours ago. With deeper moisture lagging the front, just starting to see area radars pick up on precipitation shifting into northwest Utah. Moving into the day Tuesday, the broad trough will continue to deepen through the Great Basin and gradually start to cut off a bit from the northern stream. The low level front will continue on a southeastward trajectory throughout the course of the day, with another day of strong prefrontal wind gusts developing across eastern valley locations mid morning on through the afternoon. Maintained the associated Wind Advisory headline as-is for fairly widespread south to southwesterly gusts in excess of 40 mph, but given the degree to which Monday seemed to overachieve expectations, will certainly need to keep an eye on conditions. Following frontal passage Tuesday evening, winds will begin to gradually relax. As mentioned, better precipitation chances with the system will lag the front. A more marked embedded shortwave will round the base of the trough with associated energy advecting into Utah through the morning. In combination with moisture, CAM guidance shows a fairly widespread band of precipitation developing through the morning as far south as Millard County or so, slowly progressing eastward in the hours following sunrise. Forcing with this impulse becomes a bit more nebulous as the core of the trough continues to work in by early afternoon, and in turn showery precipitation trends a bit more scattered in nature. With the colder near-surface air and marginally steeper lapse rates, meager diurnal destabilization will also support a few thunderstorms. Over the remainder of the short term forecast, the broad trough will slowly continue to shift through overhead, with limited moisture and weaker embedded impulses within the cyclonic flow maintaining unsettled and cooler conditions. In general, coverage will tend to be a little higher during the day given the aid of daytime heating. Given that the moisture is somewhat meager with the system, QPF totals aren`t too impressive, but many across the area (especially those further north) will have favorable odds to pick up at least a little bit of measurable precipitation. Given the cooler air associated with the core of the trough, snow levels actually briefly drop to around 6750-7250 ft Wednesday morning, but actual late season accumulations are more likely to be limited to areas generally at/above 8500 ft or so. Even then, outside of some of the highest peaks, accumulations look to be pretty light and minimally impactful. .LONG TERM (after 12Z/6AM Thursday)...Between Thursday and Friday, our region remains wedged between an area of low pressure over the Baja Peninsula and a deep trough traversing the northern Plains. This pattern will support continued cool and unsettled conditions through this period as west-northwesterly flow develops across the region. Temperatures are expected to gradually warm near to just below to climatological normals by Friday, translating to highs in the mid-upper 60s for most valley locations except lower Washington county where highs nudge into the 80s. A reinforcing shortwave digging into the Great Basin on Thursday will provide enough instability for widely scattered showers and thunderstorms to develop across northern Utah and southwest Wyoming on Thursday afternoon. Precipitation chances dwindle on Friday, with additional afternoon shower chances remaining generally less than 20% areawide. An upper-level trough deepens across the Pacific Northwest on Saturday, introducing increased southwesterly flow across the region and warm advection aloft. As such, temperatures are expected to jump an additional 5-10 degrees on Saturday, mainly across the northern portion of the forecast area. Gusty southwesterly winds are expected to develop mainly across southwestern Utah, with widespread gusts 20- 30 mph. Ensemble clusters support this trough digging into the Great Basin late Saturday, cutting off directly over our region late Sunday, then lingering overhead before ejecting eastward late Monday. This pattern will support widespread showers between late Saturday into early Monday, with a cooling trend back below seasonal averages. Additionally, significant cooling aloft will allow for some snowfall accumulations mainly above 8000-9000 feet between this period. && .AVIATION...KSLC...Dust lofted off of the Great Salt Lake Desert from the frontal passage continues to hang around the Salt Lake Valley early this morning, resulting in MVFR VIS. This dust will likely linger across the valley this morning until a band of post frontal precipitation moves through this afternoon, though VIS may fluctuate between MVFR/VFR during this period. Have opted to err on the pessimistic side for latest TAF package given current observations. Regardless, slantwise visibility reductions will continue until precipitation flushes out remaining dust this afternoon. High resolution guidance suggests the aforementioned precip band will impact the terminal roughly between 20-00z this afternoon, with more showery conditions through the remainder of the evening. While showers will be generally light, expect CIG reductions with resultant mountain obscuration after 18z. .REST OF UTAH AND SOUTHWEST WYOMING...Winds across the northern portion of the airspace have tapered off as northwesterly post-frontal winds prevail. Some BLDU still lingers across areas downstream of desert sinks this morning, resulting in deteriorated VIS. Behind this front, a band of light precipitation traverses the northern portion of the airspace early this afternoon, which will clear out any lingering dust. Strong southerly winds persist for southern Utah terminals as they remain ahead of the front this morning. Expect winds to finally ease and shift west-northwest as the front passes through southern Utah late this afternoon. && .FIRE WEATHER...A strong trough and associated cold frontal boundary will continue to gradually work southeast through Utah Tuesday. Ahead of the front, primarily east of Utah`s high terrain, strong gusty south to southwest winds will redevelop and afternoon humidity values will remain in the high single digits to mid teens. Winds will trend west to northwesterly behind the front and remain more modestly gusty for a period of time. Showers and a few thunderstorms will accompany the front, with forcing and moisture sufficient to then maintain shower chances behind the front into midweek as the broader/deeper system shifts through overhead. Some light snow accumulation will be possible at high elevation locations generally above 9000 feet. A series of weaker reinforcing waves will help keep an unsettled pattern continue through the remainder of the work week, especially for northern Utah. Another fairly deep and moist system then remains favored to impact Utah through the weekend. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...Wind Advisory from 9 AM this morning to 9 PM MDT this evening for UTZ120-121-126>131. WY...None. && $$ SHORT TERM...Warthen LONG TERM...Whitlam AVIATION...Whitlam FIRE WEATHER...Warthen For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity