Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 254 PM EST Sun Dec 29 2019 Valid 00Z Mon Dec 30 2019 - 00Z Wed Jan 01 2020 ...There is a slight risk of severe thunderstorms over parts of the Tennessee and Lower Mississippi Valleys... ...There is a slight risk of excessive rainfall over parts of the Ohio Valley... ...Temperatures will be 15 to 25 degrees above average from the Mid-Atlantic into the Lower Great Lakes... A major winter storm is in progress across the Upper Midwest as a strong surface low slowly tracks across the region. Heavy snow with blizzard conditions at times are expected from Eastern Dakotas and Northwest Minnesota. By Monday, the axis of heaviest snow becomes centered over Northern Wisconsin and the Upper Peninsula of Michigan with 6 to 12 inches of snow likely, with up to 20 inches near Lake Superior. Severe travel disruptions are likely for these areas through Monday. The Northeast U.S. is also expected to have impactful winter weather as a second surface low develops south of the New England Coast Monday morning. A rain/freezing rain is becoming more likely across Northern New York and into Central New England on Sunday evening into Monday, as warm air advection and moisture from the Atlantic Ocean overrides a shallow layer of sub-freezing temperatures near the surface. The potential exists for a quarter to half an inch of ice accretion, and this will likely cause havoc for travelers and disrupt electrical service. Snow and sleet should be confined farther north near the Canadian border where several inches of snow accumulation is expected. Mainly rain is expected closer to the coast and for the major cities along the Interstate 95 corridor. Elsewhere across the continental U.S., additional rainfall is expected for California through Monday afternoon as an upper-level low and surface front tracks southward along the West Coast. Mainly dry and cold conditions are forecast across the Rockies and the Southern Plains as high pressure governs the weather pattern there. Temperatures are expected to well above normal for much of the eastern U.S. on Monday, and then for the Mid-Atlantic and Southeast on Monday ahead of the cold front. A few record high minimum temperatures are possible on Monday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php