(CNN)Severe storms are forecast Friday, with possible strong tornadoes across the central Gulf Coast states and large hail -- over 2 inches -- over the Ohio Valley.
Nearly 45 million people are at risk of severe weather Friday as thunderstorms move east. This risk spans from the central Gulf Coast, northward to the Ohio Valley and eastward to the Carolina coast.
Severe storms are ongoing Friday morning over southern Mississippi into Alabama, where a tornado watch is in effect until 10 a.m. local time. The primary threats in the watch are the possibility of a couple of intense tornadoes and scattered damaging wind gusts to 70 mph.
The Storm Prediction Center (SPC) has issued an enhanced risk (level 3 of 5) for severe storms over southeastern Mississippi and much of southern Alabama, where the potential for strong tornadoes (EF-2 or greater), damaging winds and hail exists into the afternoon.
The SPC noted the forecast is "suggesting conditions will be ideal for tornadoes" in this area and that if a storm lined up just right, "then a long-track, strong tornado will be possible."
"Very large hail" possible
The storms are expected to continue eastward Friday, with areas from Columbus, Ohio, down to Wilmington, North Carolina, and south toward the Florida Panhandle and the Gulf Coast states affected.
The potential for strong thunderstorms may also impact the Cincinnati, Ohio, and Louisville, Kentucky, areas, where damaging winds and large hail are possible.
"Large hail and wind damage may also occur further north across the Ohio and Tennessee Valley, some of which could have very large hail," the SPC said. The area from far southeast Missouri northeastward across western Kentucky and into far southern Indiana has the greatest potential for hailstones of greater than 2 inches in diameter.
"Some thunderstorms may also contain excessive rainfall rates, prompting the issuance of a marginal risk (level 1 of 4) for flash flooding in Alabama and western Georgia," the Weather Prediction Center (WPC) said.
By Friday evening, rain will begin over much of the East Coast and continue through Saturday, the WPC said.
"A broad area of 0.5 - 1" of rain, with locally higher amounts in thunderstorms, is expected throughout much of the eastern US through Saturday before conditions begin to improve from west to east during the evening hours, the center said.
Additional severe storms are expected along much of the Atlantic Coast Saturday.
CNN's Pedram Javaheri and Mike Saenz contributed to this report.