Heavy rain, storms could lead to flash flood risk in state through Friday
Flash flooding will be possible across much of the Palmetto State through Friday as a slow-moving area of low pressure gradually moves into the Southeast.
An unsettled weather pattern is expected to transpire over the next 48 to 72 hours as a cutoff area of low pressure slowly moves ashore. Surface analysis Wednesday afternoon shows this area of low pressure centered about 200 miles south of Louisiana, with several troughs of lower pressure radiating out from the center of the low. A warm front was observed stretching east-southeast toward the Florida Keys, with an abundance of lightning being detected on satellite Wednesday afternoon.
Numerous showers and thunderstorms currently stretch along a frontal boundary extending from southern FL to the Gulf of Mexico. Areas of heavy rain are possible across southern FL, with gusty winds possible across the central Gulf Coast through tonight. pic.twitter.com/fRWDFxtG1z— NWS Weather Prediction Center (@NWSWPC) April 12, 2023
The meandering low pressure area is forecast to move into the Lower Mississippi River Valley by Thursday, with an attendant warm front expected to push into the Lowcountry by Thursday evening. As the warm front lifts northward, dew points across the Lowcountry are forecast to reach into the middle and upper 60s. This environment will result in a moisture-rich environment capable of producing heavy rainfall rates and localized flash flooding. The low pressure area is forecast to move into the Carolinas by Friday, bringing with it a continued chance for localized flash flooding across the Midlands and Upstate.
High-resolution weather models Wednesday afternoon suggest heavier convective activity begins along the Savannah River after sunset Thursday. Initial thunderstorm activity Thursday evening may produce strong winds or even a brief spin-up tornado, especially in coastal Georgia. Instability will be waning during the overnight hours, resulting in a small severe weather risk across the Palmetto State. While strong storms should generally be weakening during this time, the risk of flash flooding will be on the increase in the Lowcountry and Midlands. Rainfall totals of up to an inch are possible across the Lowcountry and Midlands overnight Thursday into early Friday, with locally higher amounts possible in heavier storms. Storms are forecast to be pushing through the Midlands and Pee Dee by daybreak Thursday. A few models depict a surge in storm intensity late Thursday morning as instability gradually starts to rise ahead of an approaching cold front. Areas along the Grand Strand could see a few stronger storms with a damaging wind threat push through around midday Friday before quieter weather returns by Saturday.
An unsettled pattern could linger through much of April, with the Climate Prediction Center's 8 to 14 Day Outlook showing much of South Carolina with a likelihood of above average rainfall. That same period looks to remain warm as well, with above average temperatures favored across much of the Southeast.