Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 410 AM EDT Thu Mar 18 2021 Valid 12Z Thu Mar 18 2021 - 12Z Sat Mar 20 2021 ...Severe weather threat shifts into much of Southeast and into the Mid-Atlantic region today... ...Heavy rain spreads eastward across the Appalachians into southern New England tonight before ending as snow Friday morning... ...Unsettled weather moving into the western U.S... A dynamic low pressure system that brought widespread severe weather yesterday across the Deep South will continue to track eastward through the eastern U.S. today. The threat of severe weather will likewise shift eastward across much of the Southeast and into the Mid-Atlantic today ahead of a strong cold front. Farther north, the center of the low pressure system will continue to track relatively quickly into the Mid-Atlantic region tonight. A swath of heavy rain is forecast to expand eastward across the Midwest and Ohio Valley toward the central Appalachians today north of the storm track. Meanwhile, a cold high pressure system from Canada will build across the Great Lakes. As the cold air filters in from the north, the heavy rain is forecast to change over to snow tonight across southern New England with increasingly blustery northerly winds. Parts of the Mid-Atlantic could see rain changing to a period of light snow Friday morning. The entire system, and most of its impacts, should move off into the Atlantic by Friday afternoon leaving behind windy conditions in its wake along the East Coast by Friday evening. Meanwhile, moisture ahead of the next low pressure system is entering the West Coast. This system will bring unsettled weather into the western U.S. for the next couple of days with relatively modest amounts of snow along the Cascades and the Sierra Nevada followed by mixed rain and snow across the Great Basin and northern Rockies as we head into the weekend. Temperatures will cool down across the eastern half of the country, as the storm system moves through. The Northern Plains will experience a gradual warm-up heading into the weekend as a warm front lifts through the region. Kong/Kebede Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php