Heavy rain over spread much of the Palmetto State on Friday, prompting the issuance of Flood Advisories and Warnings near the Columbia and North Augusta areas. Data from Doppler radar and rain gauges indicate that 2 to 4 inches of rain has accumulated over the Midlands through early Friday afternoon. Meanwhile, 1 to 3 inches has fallen over the Upstate. Amounts so far have been less than an inch over most of the Pee Dee, Grand Strand, and Lowcountry. Forecasters say another round of rain, and a few thunderstorms, are expected tonight before the weather system moves away on Saturday morning.
The soggy conditions are tied to a strong trough of low pressure moving eastward along the Gulf coast. A swath of high atmospheric moisture originating from the Gulf of Mexico is streaming northward ahead of this trough and is the reason for the widespread, and in some cases, heavy rain.
High resolution computer models forecast a break in the heavy rain this evening over the state, but another disturbance high in the atmosphere is expected to arrive after midnight. The second round of rain is expected to arrive around midnight in the Upstate, spreading over the rest of the state overnight. A thunderstorms may have gusty winds, especially near the coast in the Lowcountry overnight. The last of the rain is on track to exit the Pee Dee and Grand Strand on Saturday morning. The second round is expected to move faster and the latest from NOAA’s Weather Prediction Center forecasts less rain — upwards of one-half inch.
Drier conditions are expected Saturday afternoon into Sunday as high pressure builds in.