Heavy rainfall will begin as early as Wednesday morning in the greater Charleston area as Idalia moves out of Florida and into Georgia and the Carolinas, the National Hurricane Center reported Tuesday.

Four to 8 inches of rain will fall through Wednesday night. That is an estimate. The amount could be greater, the center said.

Idalia, now a hurricane as it approaches Florida, is expected to become a tropical storm once it travels over land.

There is already a tropical storm watch in effect for coastal counties in Georgia and South Carolina.

The storm surge on Thursday morning is estimated to be up to 4 feet.

Tornadoes and waterspouts will be possible.

Flooding is all but assured. Low-lying homes will be inundated. Rivers and streams will overflow their banks and creeks and canals could become rivers, the Hurricane Center said.

Driving will become dangerous. Rip currents will be commonplace. Docks could be damaged as could roofs and windows..