Heavy snow and rain/freezing rain over parts of Northern New Englandand snow over parts of the Appalachians on Sunday.There is a Slight Risk of excessive rainfall over parts of theCentral/Southern Appalachians and Mid-Atlantic on Saturday.There is a Slight Risk of severe thunderstorms over parts of theSoutheast on Saturday.A wave of low pressure over the Lower Mississippi Valley movesnortheastward to the Mid-Atlantic by Sunday, then out over the WesternAtlantic by Monday. Moisture will surge northward over the Southeast intothe Mid-Atlantic, producing heavy rain. Therefore, the WPC has issued aSlight Risk of excessive rainfall over parts of the Central/SouthernAppalachians and Mid-Atlantic through Sunday morning. The associated heavyrain will create mainly localized areas of flash flooding, with urbanareas, roads, and small streams the most vulnerable. Moreover, light snowwill fall over parts of the Lower Great Lakes along the northern edge ofthe precipitation shield.Additionally, showers and severe thunderstorms will develop over parts ofthe Southeast. Therefore, the SPC has issued a Slight Risk of severethunderstorms over parts of the Southeast through Sunday morning. Thehazards associated with these thunderstorms are frequent lightning, severethunderstorm wind gusts, few tornadoes, and a minimal threat of hail.On Sunday, rain will continue over the Ohio Valley to the Mid-Atlantic andshowers and thunderstorms will develop over parts of Coastal Mid-Atlanticinto Florida. However, the threat of severe thunderstorms and excessiverainfall will end on Sunday.Also, as the precipitation shield moves into colder air on Sunday, snowwill develop from parts of the Ohio Valley/Lower Great Lakes to NewEngland. Heavy snow will develop over parts of Northern New England, whilepockets of rain/freezing rain will develop from parts of eastern New YorkState into Southern New England. Snow will also develop over parts of theCentral/Southern Appalachians. By Monday morning, the area of low pressurewill be over the Western Atlantic.Meanwhile, moisture will stream into the Pacific Northwest and NorthernCalifornia, mainly producing rain and highest-elevation snow in a fewplaces. The rain will continue over the Pacific Northwest through earlySunday afternoon. The rain will be over by Monday morning.