Communities in the South are grappling with dangerous flooding from heavy rainfall, while dense fog envelops a swath of the U.S. Major flash flooding struck Wednesday from Louisiana to Mississippi, where rainfall totals ranged from 5 to 9 inches. Over th

(NEW YORK) — Communities in the South are grappling with dangerous flooding from heavy rainfall, while dense fog envelops a swath of the U.S.

Major flash flooding struck Wednesday from Louisiana to Mississippi, where rainfall totals ranged from 5 to 9 inches. Over the past few days, heavy rain also hit parts of eastern Texas, just north of Houston, where more than 8 inches fell.

On Thursday, the worst of the flooding is hitting Louisiana, Mississippi, Alabama and Tennessee.

More rounds of heavy rain are on the way, so flood watches remain in effect through Saturday from Birmingham, Alabama, to Atlanta.

The heavy rain is also striking the Midwest and the Northeast.

By Thursday night, the rain will stretch from Illinois to Virginia. Flood watches are in effect for parts of the Great Lakes, Mid-Atlantic and Northeast because the rain is falling on top of the snowmelt and ice jams.

By Friday morning, the rain will push north into Wisconsin and upper Michigan, and the temperature is expected to be cold enough to turn the rain to snow in some spots.

New England will see an icy mix of rain, freezing rain and sleet during the Friday morning commute.

Meanwhile, millions of Americans woke up Thursday to extreme fog in at least 25 states from New Mexico to New York.

There were reports of near-zero visibility in cities including New Orleans, Chicago and Little Rock, Arkansas. Low visibility was also reported in New York and Philadelphia.

Some areas will see this dense fog through most of the day.

The East Coast is also seeing a major warm up.

On Thursday, temperatures are expected to be near 60 degrees in Washington, D.C., in the 50s in New York and near 50 in Boston.

The mild air is forecast to linger over the next few days, with temperatures near 50 degrees in New York, in the 70s for Atlanta and a summer-like 80s for Orlando, Florida.