Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 300 AM EST Sat Jan 20 2024 Valid 12Z Sat Jan 20 2024 - 12Z Mon Jan 22 2024 ...Heavy rain expected to impact northern to central California today and early Monday, with heavy wet snow along the Sierra Nevada... ...More freezing rain is forecast for the Columbia River Basin... ...Arctic air will dominate the eastern two-thirds of the country with lake-effect and upslope snows remaining active today... As the latest round of snow rapidly departs the northeastern U.S., a large dome of arctic high pressure system will dominate the eastern two-thirds of the country through the weekend. While this arctic outbreak will not be as cold as the previous one, sub-zero temperatures will reach as far south as Missouri and Kansas this morning. Farther south, below freezing temperatures will overspread much of the Gulf Coast region except southern Texas and the southern half of the Florida Peninsula. Wind chill temperatures as low as -20 to -30 will be common across the northern Plains this morning. The frigid air passing over the relatively warm waters of the Great Lakes will continue to trigger more lake-effect snow downwind from the Great Lakes today. Additional upslope snow is also expected today from West Virginia to southwestern Pennsylvania. The center of the arctic high pressure system is forecast to slide eastward and reach the Mid-Atlantic region by Monday morning. With no additional replenishment of arctic air from Canada, a steady warm-up is forecast for the mid-section of the country on Sunday. Deep return flow behind the high pressure system will begin to set up a channel of moisture from the Gulf of Mexico into the southern Plains late Sunday into Monday. The chance of heavy rain is expected to increase quickly across southern Texas Sunday night into Monday morning. Meanwhile, a potential of mixed precipitation and ice is expected to surface farther north toward Oklahoma by Monday morning. Along the West Coast, multiple frontal systems arriving from the Pacific will bring active weather onshore through the weekend and into Monday. Heavy rain will likely impact northern California especially today, as well as by Sunday night into Monday, with heavy wet snow expected to linger along the Sierra Nevada. In addition, the influx of warmer air aloft over the trapped cold air near the ground will support more ice/freezing rain for the Columbia River Basin and especially the Columbia Gorge for the next few days. Mixed precipitation will begin to penetrate further inland, reaching into the Four Corners by Monday morning ahead of an upper-level trough. Unsettled weather will also continue along the coast of the Pacific Northwest. Kong Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php