410 FXUS65 KSLC 230441 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 941 PM MST Fri Feb 22 2019 .SYNOPSIS...High pressure aloft will spread into the area Saturday, with a transition to a more westerly flow Sunday through the early part of next week. && .SHORT TERM (Through 00Z Tuesday)...The upper level trough currently along the Utah/Colorado border will continue east out of the Utah tonight. Replacing this trough will be a low amplitude upper ridge with a stable and significantly drier air mass. By Sunday a zonal pattern will set up across the western CONUS which will bring a somewhat milder air mass across the region continuing into early next week. The last of lingering snow showers should end by midnight. Mostly clear skies, decreasing winds and a rather cold air mass aloft will drive temps down well below late February norms for Saturday morning. Not anticipating any significant valley fog development overnight. Temperatures this afternoon for the most part failed to climb above, or even close to, freezing in areas with new snow (outside of the St. George area). Patchy late night fog can't be ruled out, but not expecting this be a significant impact event either. Heights will gradually rise as ridging builds into the area Saturday. This ridging will transition into a zonal pattern across the area Sunday/Monday. Somewhat milder temperatures will follow, with readings approaching seasonal norms by Monday. Any precip in the short term period will come Sunday/Monday and will be confined to the Idaho border region. Increasing low-level and somewhat moist warm advection will be the main driver of lift. This lift will remain rather shallow, so any precip that does develop will remain on the light side. .PREVIOUS LONG TERM (After 00Z Tuesday)...The zonal weather pattern leading up this extended period will buckle into a weak ridge Tuesday into Wednesday as a trough develops upstream off the Pacific NW coast. With this ridging the current trend of backing off on the PoPs seems reasonable. The EC ensemble appears to have the best handle on this scenario which is the driest solution. Have boosted temps a few degrees over the southwest to be closer to MOS guidance Tuesday and Wednesday. Have held onto current temps across the north but would not be surprised that they too will need to be bumped upward. The GFS seems to be too aggressive in bringing QPF southward across the CWA as the dynamics associated with the storm track remains mostly in Idaho and the extreme northern portion of Utah through Thursday. The deterministic GFS run shows a strong cold front moving into Utah Thursday night into Friday but the GFS ensemble mean/EC/Canadian do not support this, so the GFS was thrown out. Temperatures during this extended period are expected to run from slightly above normal to as much as 5-10 degrees above normal. && .AVIATION...Stable high pressure and a drier air mass will move across northern Utah tonight through Saturday. VFR conditions will prevail with generally light winds through the current TAF period. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...None. WY...None. && $$ CONGER/STRUTHWOLF 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