Area Forecast Discussion
Issued by NWS Salt Lake City, UT
Issued by NWS Salt Lake City, UT
961 FXUS65 KSLC 081009 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 409 AM MDT Wed May 8 2024 .SYNOPSIS...Widespread precipitation has ended, but the storm system responsible will morph into a cutoff low that will meander and weaken across Utah through the weekend. This will allow temperatures to gradually warm with isolated afternoon showers and storms through the weekend, particularly across central and southern Utah terrain and adjacent valleys. Additionally, east winds Thursday and Friday will create gusty conditions along lee side terrain and near canyons for northern and central Utah. && .SHORT TERM (Through 12Z/6AM Friday)...Radar shows that most of the precipitation has ended across the area, and so far the lake effect snow band that hi-res guidance was advertising has not materialized. Assuming this band does not develop, the main features to focus on across the area will be the freezing temperatures across some valley locations and northerly gap winds across lower Washington county. The gap winds across lower Washington county, where gusts have been as high as ~50 mph in spots, will continue to gradually diminish allowing for the wind advisory to expire at 14Z. Some mid level clouds are keeping temperatures a few degrees warmer, but there are still freezing temperatures across The Swell, Box Elder, Tooele, and Utah counties where freeze warnings remain through the morning hours. More diurnal showers will develop across northern Utah/SW Wyoming this afternoon. These showers will be similar to today: short- lived, containing graupel and locally gusty winds, and the potential for some isolated lightning. This trough responsible for the unsettled weather will cut off from the mean flow and leave a closed low across Utah on Thursday. Given that almost all of the guidance has shifted to this solution, showery afternoon precipitation will remain across central and northern Utah. With the cyclonic flow around this low pressure, easterly winds aloft will direct these showers from east to west mainly on the east facing aspects of the terrain. These easterly winds will also help to enhance the potential for some low end downsloping and canyon winds along the leeward side of the terrain of northern Utah and the Book Cliffs. .LONG TERM (After 12Z/6AM Friday)...The beginning of the long term period will feature an upper low cut off from the main belt of westerlies as it spins across the central Great Basin. Easterly flow along the poleward side of this low will be maintaining a downslope wind event along the northern Wasatch Front and eastern Cache Valley. High-res guidance suggests this event will be peaking early Friday morning with gusts in the 45-55 mph range (70% probability) with perhaps the most favored spots such as Park Lane in Farmington occasionally exceeding 60 mph. With the upper low spinning over the region, cold air aloft coupled with daytime heating will support diurnally driven convection Friday and likely Saturday as well. By Sunday, the consensus is to begin lifting this low out of the region. Roughly 30% of ensemble members delay this eastward progression until late Sunday into Monday, maintaining a chance of convection Sunday afternoon, however the majority of ensemble guidance begins building shortwave ridging across the eastern Great Basin by late Sunday. Temperatures through the weekend will gradually modify despite the presence of the upper low. Max temperatures by Friday afternoon will run near to slightly below climo, then trend 3-5F warmer Saturday and again Sunday. This warming trend will continue into Monday, before heights lower in response to a shortwave trough digging through the northern Rockies during the middle of next week. && .AVIATION...KSLC...There is a 20% chance of snow showers impacting the terminal through 15Z, otherwise VFR conditions will prevail through the period with CIGS in the 4000-6000 ft range persisting through the morning before scattering out by 18Z. Surface winds will remain from the northwest throughout the day. .REST OF UTAH AND SOUTHWEST WYOMING...VFR Cigs in the 4000-6000 foot range will persist across northern Utah and southwest Wyoming this morning before scattering out this afternoon. A northerly gradient will maintain northerly surface winds across the region throughout the day today. && .FIRE WEATHER...Widespread precipitation will transition to isolated afternoon showers and storms for Wednesday across northern Utah. These isolated afternoon showers will shift into central and southern Utah Thursday through the weekend as a cutoff low meanders across the state. These showers will mainly be confined to the terrain and eastward facing aspects along with adjacent valleys. Additionally, expect breezy easterly winds to develop on the west side of terrain close to canyon mouths and benches on Thursday and Friday across northern and central Utah. Temperatures will gradually warm as this low weakens. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...Freeze Warning until noon MDT today for UTZ102-103-106-121-130. Wind Advisory until 8 AM MDT this morning for UTZ123. WY...None. && $$ SHORT TERM...Mahan LONG TERM...Seaman AVIATION...Seaman FIRE WEATHER...Mahan For more information from NOAA`s National Weather Service visit... http://weather.gov/saltlakecity