Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 249 AM EST Thu Jan 28 2021 Valid 12Z Thu Jan 28 2021 - 12Z Sat Jan 30 2021 ...Excessive heavy lower elevation rain to bring dangerous flash flood risk to coastal central California 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 through early Thursday morning... Significant rainfall is occurring over parts of central California at lower elevations as an atmospheric river and a robust Pacific storm system tracks inland. Amounts of 7 to 10 inches are expected for this regions and 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; which are reserved for rare events where flash flooding is likely to put lives and property in danger. In addition to the heavy rainfall, higher elevations are getting hammered with extreme snowfall. Several feet of snow (as much as 10 feet in total accumulation) will be possible for the Sierra Nevada through Friday morning. These conditions will likely cause road closures and travel delays. Winter Storm Warnings and Winter Weather Advisories blanket the region, along with Blizzard Warnings for parts of the Sierra Nevada where gusty winds will accompany the heavy snow. The heavy precipitation is anticipated to diminish by Friday. Scattered to widespread rain is expected across portions of the Southeast and lower Mid-Atlantic region into Thursday morning as a surface low pressure system tracks 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. The surface low is expected to rapidly strengthen offshore the Southeast Coast Thursday morning. As this takes place, temperatures will continue to fall across parts of the Mid-Atlantic region and will help generate a few inches of snowfall across parts of southern Virginia and the mountains of northern North Carolina. Accumulations up to 6 inches may be possible. Winter Weather Advisories currently stretch from eastern Kentucky to coastal North Carolina. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php