A powerful complex of thunderstorms will bring the risk of damaging winds, large hail, and strong tornadoes to portions of the Palmetto State through Thursday.
Surface analysis Wednesday morning depicts a stationary boundary draped across the Deep South, stretching from Georgia to Texas. South of that boundary, southerly winds have allowed for dew points across the Deep South to climb into the middle and upper 70s as daytime heating warms the surface. In the mid- and upper-levels, a fast-moving pocket of air known as a jet streak is producing winds of more than 60 miles per hour from Texas to the Mid-Atlantic. Temperatures in this region of the atmosphere are well below freezing, resulting in an abnormally explosive environment for severe thunderstorm development by mid-June standards in the Deep South. These ingredients will combine with ample fuel for thunderstorm development, culminating in a likely widespread severe weather outbreak through Thursday.
Forecast data as of publishing suggests a few isolated strong and severe storms will be possible through the early afternoon Wednesday. A second, potentially more potent round, is expected to move in Wednesday evening before midnight. This round is expected to bring the highest risk of severe weather to portions of the Midlands and Lowcountry. A third round of strong storms appears possible during the pre-dawn hours Thursday, especially focused along and south of I-26.
The Storm Prediction center has an "enhanced" risk, or a 3 on a scale of 1-to-5, in and around Hilton Head Island towards Savannah, Georgia. This means numerous strong and severe storms will be possible through early Thursday morning. A "slight" risk, or a 2 on the 1-to-5 scale, is in place as far north as I-26. This designation indicates that severe storms will likely be widely scattered across the Midlands and Lowcountry. From I-26 northward to the North Carolina border, a "marginal" risk is in place, which is a 1 on the 1-to-5 scale. This means severe storms through Thursday morning are likely to be less widespread and more isolated in nature. Regardless of severe risk, residents are encouraged to have multiple ways to get severe weather alerts since storms could move through while many are asleep.
All severe weather risks are possible Wednesday into Thursday, especially along and south of I-26 in the Midlands and Lowcountry. The first round of storms that develop through Wednesday afternoon will be capable of producing localized areas of damaging winds and a few reports of large hail. The risk of tornadoes through Wednesday evening will mainly be across Alabama and Georgia as storms initially develop closer to the stalled frontal boundary. Large swaths of damaging wind will be prominent with the second round of thunderstorms that arrive to the southern Midlands and Lowcountry Wednesday evening. Wind gusts could be in excess of 70 to 80 miles per hour, which could result in damage equivalent to an EF-0 or EF-1 tornado. The atmosphere will support a rare large hail threat for mid-June in the Southeast, with the Storm Prediction Center forecasting the possibility of hail up to 3 inches in diameter across the Lower Mississippi River Valley. Closer to the Palmetto State, hail could be as large as 2 inches in diameter as storms blast through overnight Wednesday into Thursday. The risk of tornadoes will be present through Thursday morning, though the ingredients for strong and long-track tornadoes will be found mainly west of South Carolina.
The risk of severe storms should push south of the state by Thursday and Friday, though the pattern does support continued rounds of thunderstorms state-wide through the upcoming weekend. Residents are encouraged to remain weather aware through the remainder of the week.