222 FXUS65 KSLC 080921 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 321 AM MDT Wed May 8 2019 .SYNOPSIS...Cool and unsettled weather conditions will persist today over Utah and southwest Wyoming. The focus of showers and thunderstorms will shift into southern Utah beginning Thursday as northern portions of the forecast area see a drying and warming trend into the upcoming weekend. && .SHORT TERM (Through 00Z Sunday)...The California storm system that moved across Arizona yesterday continues to weaken as it passes through New Mexico. A second weak Pacific Northwest storm system is currently making its way through northern and central Utah. The combined efforts of these storm systems are producing a few areas of generally light showers across portions of the state in a relatively cool and unsettled airmass. Coverage of showers is anticipated to increase again by this afternoon with daytime heating, as well as additional instability provided by another Pacific Northwest wave moving into northern Utah late this afternoon/early this evening. This second Pacific Northwest storm system is progged to slide into Nevada tonight before moving into California Thursday evening. The location of this system is progged to shift the flow aloft over the forecast area to a more E/NEly direction, with a favorable gradient allowing for good cold advection from southwest Wyoming. These ingredients will result in conditions favorable for downslope/canyon winds over prone areas of northern Utah. Overall, flow aloft in the overnight model runs is looking more northerly, which is not quite as favorable, but still think the potential exists for some marginally advisory level winds tonight. However, confidence is not high enough to issue any headlines at this time. As the storm system makes its way into California, the focus of moisture and instability over the forecast area will shift to southern Utah, keeping relatively cool conditions and the threat of showers and thunderstorms there as northern Utah and southwest Wyoming see a general warming and drying trend into the weekend. .LONG TERM (After 00Z Sunday)...Ridging slowly builds across the northern Rockies late week, then into the Great Basin early next week. An anticyclonic drying/stable airmass builds in from north to south. This suppresses convective development across the north, shunting deep layer moisture south toward the Arizona border next weekend. Main uncertainty during the extended forecast, is how quickly enough moisture builds north within potential return flow early next week, to support convective development along the spine of the mountains. Some guidance develops a deep eastern Pacific trough mid-week which may add additional moisture and lift across the region supportive of more widespread convective activity. The building ridge will support warm temperatures through the extended forecast period. && .AVIATION...Light southeast drainage winds at the KSLC terminal early this morning will likely switch to out of the northwest around sunrise and become gusty for the afternoon. Mountains will likely remain obscured due to low ceilings through much of the day. Shower activity is most likely during the afternoon, and these may lower ceilings further, and may restrict visibilities as well. Strong gusty/erratic microburst winds look to be a lower probability today compared to the past 2 days. Downslope/Canyon wind event likely to occur to the north of the KSLC terminal this evening, persisting at times into Friday morning. This usually causes variable but impactful winds at KSLC due to eddies off the terrain, as well as the potential for low level wind shear north of the airfield. && .FIRE WEATHER...A series of storm systems impacting the district will keep relatively cool and unsettled conditions in place through much of the remainder of the work week. Showers and thunderstorms will be most widespread across Utah today before the precipitation focus shifts to southern Utah beginning Thursday, with the threat of showers lasting through the upcoming weekend. Temperatures will steadily warm over northern portions of the district beginning Friday, with showers acting to limit warming over southern Utah. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ SHORT TERM/FIRE WEATHER...Traphagan LONG TERM/AVIATION...Rogowski For more information from NOAA's National Weather Service visit... http://weather.gov/saltlakecity For frequently asked questions about the Area Forecast Discussion visit... http://weather.gov/saltlakecity/general/afd_faqs.php