Over 56 million Americans under flood watch Sunday and Monday

A flood watch affecting more than 56 million Americans has been issued across 12 states, as a storm system is expected to bring severe weather to the East Coast on Sunday and Monday.

The flood watch is in effect from the Mid-Atlantic to the Northeast, beginning Sunday afternoon and continuing into Monday afternoon. This includes D.C.; Baltimore; Philadelphia; New York City; Albany, New York; Hartford, Connecticut; Burlington, Vermont; and Portland, Maine.

Rainfall totals could reach 2 to 4 inches, with some rainfall rates of half an inch per hour possible. If this moderate rainfall rate lasts over one area too long it could lead to quick runoff and urban flash flooding.

There's a "slight risk" of excessive rainfall leading to flash flooding for parts of the coastal Northeast on Sunday, the National Weather Service said.

The rain is forecast to hit from the Florida panhandle up to near D.C. around 7 a.m. Sunday. By Sunday evening, moderate to heavy rainfall is expected to fall along the I-95 corridor.

High winds are also expected for coastal Long Island into New England later on Sunday, with wind gusts up to 60 mph possible. All of Long Island, Cape Cod and coastal Maine are under a high wind watch.

Travel from Sunday night into Monday morning is not recommended, when the heaviest rain is expected.

The NYC Emergency Management Department has issued a travel advisory for Sunday and Monday due to the potential for flooding rain and strong gusty winds.

By 7 a.m. Monday, most of the heavy rain is expected to be north of New York City and starting to exit Boston.

Heavy wet snow is also possible in upstate New York and Vermont through the afternoon. Total snow accumulations of 4 to 10 inches, with up to 15 inches locally, are possible.

Elsewhere, a moderate to strong atmospheric river is forecast to bring another period of steady rain to the Northwest late Saturday into Sunday. The most likely scenario calls for 1.5 to 2.5 inches of rain falling along the immediate coast, and up to 3 to 4 inches of rain falling across the north Oregon Coast Range.

In the South, severe thunderstorms capable of producing a few tornadoes, scattered damaging winds and large hail are possible Saturday afternoon and evening, from Louisiana to Kentucky.

A tornado watch is in effect until 7 p.m. CT for parts of Kentucky, Tennessee, Mississippi and Arkansas.

A confirmed powerful tornado moved through northwest Tennessee Saturday afternoon. Early damage reports are coming in from Dresden and Rutherford.

This line of storms has the potential to spawn more tornadoes, as well as large hail and damaging winds, into the evening.