Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 311 AM EST Thu Jan 02 2025 Valid 12Z Thu Jan 02 2025 - 12Z Sat Jan 04 2025 ...Long duration lake-effect snow event continues downwind of the Great Lakes... ...Periods of locally heavy coastal rains and higher elevation snow continue for much of the northwestern U.S.... ...Arctic air surges south from the Northern Plains through the Central and Eastern U.S.... Strong northwesterly winds on the backside of a departing low pressure system that is moving into the Canadian maritime will generate moderate to heavy lake enhanced snow downwind of the Great Lakes over the next few days. Anywhere between 6-12 inches of snow with isolated higher amounts may accumulate downwind of the Lakes by Saturday morning. A low pressure system tracking across the Central U.S. will produce a light swath of snowfall from Iowa across the Ohio Valley today and into the Central Appalachians on Friday. Snowfall accumulations of 6-12 inches are possible over the Central Appalachians. A series of low pressure systems will generate rain and high elevation snow across much of the Northwest over the next couple of days. The moisture plume associated with the first system will be directed at the northern California coast and Oregon today, where an isolated threat of Flash Flooding exists. Snow showers continue over the Northern/Central Rockies. Rain and snow showers expand in coverage across the Northwest on Friday. Accumulating snow is possible over the highest elevations of the Cascades, Sierra and Northern Rockies. Heavy rainfall expands into the upslope areas of the Sierra as the cold front pushes through. High pressure builds over the Great Plains, sending frigid arctic air down through the Central and Eastern U.S. through the weekend. Meanwhile, the West and Southern Plains will experience above average temperatures. There also continues to be an elevated fire weather threat over parts of southern California today. Kebede Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php