Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 348 PM EDT Sun Mar 22 2020 Valid 00Z Mon Mar 23 2020 - 00Z Wed Mar 25 2020 ...Periods of rain in portions of Southern California and heavy snow in the central Sierra Nevada today, heavy snow accumulations possible in the higher elevations of the Northwest early week...... ...Coastal storm may produce heavy rain in the Northeast megalopolis, heavy snow in the northern Appalachians... ...West Coast system to track into the Heartland late Monday and Tuesday, severe weather and heavy rain possible in the Plains and Mississippi/Ohio Valleys... Starting in Southern California, a wave of low pressure will approach from the west causing showers and thunderstorms to move ashore this evening. Rainfall rates could approach one inch per hour around the Los Angeles metro area. As a result, a Slight Risk for excessive rainfall is in place for the city and neighboring suburbs. The threat for flash flooding extends as far north as the southern suburbs of the Bay Area. Further inland, snow is likely to fall in the southern Sierra Nevada with over 8 inches possible in the highest elevations. As this storm system moves est on Monday, an upper level trough will enter the fray over the Pacific Northwest leading to coastal/valley rain and mountain snow through mid-week. The higher elevations of the Cascades and Sierra Nevada may be measuring snowfall by the foot into the middle of the week. Switching coast lines, showers and thunderstorms tracking through the Ohio Valley this afternoon will head for the eastern Great Lakes and northern Mid-Atlantic tonight while an area of low pressure strengthens near the North Carolina Outer Banks Monday morning. As the storm intensifies off the DelMarVa coast Monday afternoon, periods of rain will develop along and east of I-95. Rain will fall heavily at times from New Jersey to southern New England where rainfall amounts in excess of 2 inches are possible. Farther north, cold air remains entrenched in the northern Appalachians causing precipitation to fall as snow. The Poconos, Catskills, Adirondacks, Berkshires, Green and White mountains will all have the potential to receive over 8 inches of snow resulting in various winter related watches and warnings/advisories being issued through Tuesday morning. The storm will be fast moving and drier conditions will return across the Northeast some time Tuesday morning. While one storm exits, the storm system impacting southern California this evening will track through the Four Corners region on Monday with spotty valley showers and mountain snow possible. By Monday night, a developing area of low pressure in the lee of Rockies will form and additional showers and thunderstorms will form over the Central Plains. A Slight Risk for severe weather is in place for parts of the region late Monday. This storm system will then head for the mid-Mississippi Valley Tuesday night with periods of rain and thunderstorms breaking out across the Ohio and Tennessee Valleys. The threat for severe weather will also move east into the Mid-South on Tuesday. Mullinax Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php