Heavy rain will soon replace the mostly dry weekend over the Palmetto State starting Tuesday afternoon and lasting into midday Wednesday. The rain may cause localized areas of street flooding and is expected to fall on top of river basins that are already flooding.
Gauge and radar data from the National Weather Service are showing rainfall departures between 150 and 300 percent of average during the month of February. The areas most affected have been over the Pee Dee, Lowcountry, and Midlands, but even the Upstate has seen its share of cloudy, wet days. Nearly the entire state has experienced above average precipitation in 2021 according to these same data -- a trend that has spilled over from 2020.
Recent rains in the Carolinas have run off into rivers in the state, causing widespread minor river flooding over the Lowcountry and Pee Dee. Moderate flooding is taking place on the Edisto River near Givhans Ferry and the Waccamaw River near Conway in Horry county is experiencing major flooding. Last Friday's gauge reading at Conway of 15.61 feet is in the top 7 recorded crests in the history of that location, dating back to the 1890s.
Another 1 to 3 inches of rain is forecast beginning Tuesday afternoon and lasting until about midday Wednesday. This new rain may lead to pockets of flash flooding. River stages are forecast to gradually recede in the coming days, but may be held higher than they otherwise would with rain from the approaching weather system.
Drier conditions are forecast Wednesday night through at least Friday behind a cold front, which should help to ease river levels some more. Assuming rain from Tuesday night and Wednesday is not much heavier than currently forecast, the Waccamaw River should fall from major flood stage to moderate flood stage over the weekend.