010 FXUS65 KSLC 062250 AFDSLC Area Forecast Discussion National Weather Service Salt Lake City UT 350 PM MST Wed Mar 6 2019 .SYNOPSIS...The very moist air mass over Utah combined with a series of passing weather disturbances will bring widespread, and at times heavy precipitation through the end of the week. && .SHORT TERM (THROUGH 00Z SUNDAY)... Period of moderate to heavy rain in and around Dixie will gradually end through early evening as the Atmospheric River is displaced eastward. Best precipitation moving forward tonight into tomorrow morning will be across the north where the shortwave will cross overhead. Kept convective wording and the mention of thunder this evening due to weak instability. Snow is expected to fill in across southwest Wyoming and should impact travel around sunset. This advisory may need to be extended overnight into tomorrow morning. Cold advection wanes tomorrow morning, with warm advection expected to develop tomorrow afternoon. Given the moist unstable environment, this appears likely to maintain active, but less impactful weather across the region during this period. Tomorrow night the influence of the next storm system is felt by another increase in winds, with precipitation becoming more widespread. Stronger height falls begin Thursday night due to dynamical forcing in the form of PVA and left exit region of a cyclonic mid and upper level jet. Most valleys remain rain or a rain/snow mix tomorrow night ahead of the approaching cold front. Cold front crosses the state from the west Friday afternoon and evening, bringing snow to the valley floor. Most valleys should see minor accumulations, with areas near Idaho, southwest Wyoming and Wasatch Back potentially seeing several inches. Northwest orographic flow post frontal will bring the Wasatch another round of significant accumulations before strong height rises and warming aloft end the threat of widespread precipitation Friday night into Saturday morning. .LONG TERM (AFTER 00Z SUNDAY)... The general upper level pattern in the long term will be characterized by a rather expansive upper level trough centered off the Pacific coast slowly progressing through the forecast area this weekend/early next week and a secondary cold push moving into Utah mid next week. Starting with the first trough...EPS and NAEFS ensemble guidance has been consistent with deepening a trough off the SoCal coast over the course of the day Sunday with weak induced ridging developing over eastern Utah. EPS ensemble mean guidance is indicating anomalously low H5 heights with this trough, with areas off the Pacific coast reaching the climatological mean for this time of the year. This, combined with an active southern branch of the Polar Front Jet centered over the Baja of California, increases confidence of a splitting system moving through the forecast area late Sunday through Monday. A majority of the system's energy is expected to remain south of Utah, focusing a majority of the precipitation across southern Utah and on the light side due to weak synoptic lift. Deterministic guidance has struggled to come to an agreeable solution, therefore the current forecast package has sided towards the ensemble means. Continuing into Tuesday-Wednesday, the upper level low is expected to be near the four corners region with a secondary cold push sliding south over the NW CONUS along the backside of the trough. Ensemble guidance projects the coldest air to move through the forecast area Tuesday night into Wednesday, which should expand precipitation across the entire forecast area with an associated surface cold frontal boundary. This should drop snow levels to the valley floors mid next week, however no significant accumulation is expected ATTM. && .AVIATION... South winds will prevail at KSLC terminal through Thursday morning before becoming westerly Thursday afternoon, with a chance of briefly becoming northwesterly for late afternoon. Winds will switch back to the south Thursday evening. Occasional showers and virga will mainly keep ceilings below crest level into Thursday morning, and occasionally result in MVFR ceilings. Showers should diminish by Thursday afternoon, allowing for some improvement in ceilings. && .SLC WATCHES/WARNINGS/ADVISORIES... UT...Winter Weather Advisory until 10 AM MST Thursday for UTZ007>010- 517-518. WY...Winter Weather Advisory until 9 PM MST this evening for WYZ021. && $$ SHORT TERM...10 LONG TERM...Bonnette AVIATION...Church 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