Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 220 PM EST Wed Jan 27 2021 Valid 00Z Thu Jan 28 2021 - 00Z Sat Jan 30 2021 ...Excessive heavy lower elevation rain to bring dangerous flash flood risk to coastal central California tonight and into Thursday... ...Extreme snowfall amounts expected across the Sierra Nevada through early Friday... ...A quick burst of light to moderate snow to impact portions of the southern Appalachians and southern Mid-Atlantic tonight through early Thursday morning... A moderate to heavy rainfall event is ongoing across central California and will spread south on Thursday as a robust Pacific front and associated atmospheric river moves inland. Deep moisture will be directed onshore and will help produce several inches of rain along the coast and lower elevations. Flash flooding and debris flows near recent burn scars are likely. WPC has highlighted part of this region as having a High Risk for excessive rainfall through Thursday morning. These delineations are reserved for rare events where flash flooding is likely to put lives and property in danger. Up to 7 to 10 additional inches of rain could fall over the next two days across the region. Higher up in elevation, mountain snow will likely be heavy at times across the Sierra Nevada. Several feet of snow (as much as 10 feet in total accumulation) will add up through Friday morning, with road closures and travel delays very likely. Numerous locations have Winter Storm Warnings and Winter Weather Advisories in effect. Blizzard Warnings are also in effect for parts of the Sierra Nevada where gusty winds will accompany the heavy snow. Much of the heavy precipitation across California and the Southwest will come to an end on Friday Further east, scattered to widespread rain is expected to move through parts of the Southeast and lower Mid-Atlantic region tonight and into Thursday morning as a low pressure system moves across the region. With cold Canadian air settling in over the central U.S. behind an associated cold front, snow will spread from the lower Ohio Valley to the southern Mid-Atlantic. Early on Thursday, the area of low pressure is expected to rapidly strengthen off the Southeast coast. This will help draw even colder air across portions of Virginia and northern North Carolina. As a result, a few inches of snow can be expected here with as much as 6 inches of snowfall possible across the mountains of North Carolina and southern Virginia. Winter Weather Advisories currently stretch from southern Illinois to northeast North Carolina. Snell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php