Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 300 AM EST Mon Jan 08 2018 Valid 12Z Mon Jan 08 2018 - 12Z Wed Jan 10 2018 ...Potential for mudslides and other hydrologic issues along the California coast, especially where burn scars exist from previous wildfires... ...Widespread threat for freezing rain extends from the Atlanta metro area up to the Mid-Atlantic on Monday... ...Milder conditions to prevail over much of the country as arctic air retreats... A system currently out over the open waters of the east-central Pacific will continue strengthening on its southeastward approach toward the southern/central California coast. This will come in the form of a powerful closed low which is forecast to be accompanied by a vast plume of moisture emanating from the subtropical Pacific. Heavy rainfall should spread from north to south as the attendant cold front approaches the coast. Based on the latest forecast, a broad area of 2 to 4 inches of rain is expected from coastal northern California down toward the Los Angeles basin. Local orographics could easily augment these amounts where favorable upslope flow will increase rainfall rates. A major issue will be the burn scar areas after a very active fire season to conclude the year 2017. These regions in particular will be susceptible to mudslides, debris flows, or other hydrologic issues given the heavy rainfall expected. Farther inland, the Pacific storm should be more wintry in nature as 12 to 18 inches of snow is likely over the southern/central Sierra Nevada ranges. A pair of disturbances sweeping through the central Gulf Coast and Great Lakes, respectively, will keep widespread precipitation in the forecast over the eastern third of the country. While moderate to locally heavy rainfall is possible along the central/eastern Gulf Coast, a wintry mix will be more commonplace from the mid-South northward. Given much of the eastern United States has been under the influence of persistent arctic air, it will be a challenge to completely scour its presence out. With mild air overriding these subfreezing surfaces, the recipe for freezing rain is in place with light ice accumulations expected across northern Georgia up through the interior Carolinas and into the central Appalachians and Mid-Atlantic. While expected amounts should be light, travel may be hazardous at times, particularly over any untreated road surfaces. Consequently, winter weather advisories are in effect over these regions for much of Monday. After a frigid start to the new year, much milder conditions are to prevail given the strong influence of air masses with a maritime origin moving through. Except for the cold temperatures on Monday where freezing rain is expected as well as the cloudy/rainy set up over California, a vast majority of the country can expect above average temperatures through mid-week. The most anomalous warmth is likely over the center of the country given downsloping flow aiding in the process. By Tuesday, high temperatures may exceed 20 degrees above climatology across the central/southern High Plains as readings move into the upper 60s to low/mid 70s. Rubin-Oster Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php