A complex of strong thunderstorms, a few of which will be capable of producing wind damage, is forecast to move across the Palmetto State early Thursday morning. A stray thunderstorm or two is also possible Wednesday afternoon across the northern tier of the state, capable of producing gusty winds and small hail.
Several disturbances are skirting a large ridge of high pressure centered over the Gulf of Mexico, similar to spokes around a wheel. One "spoke" is expected to ignite thunderstorms over Alabama and Georgia Wednesday afternoon, but most of these storms are favored to stay south of the state. Another "spoke" approaching from Tennessee is likely to ignite scattered strong storms not far from the Spartanburg area between 3 and 5 PM, moving quickly to the Rock Hill region between 5 and 8 PM, and finally to the Florence and Myrtle Beach areas shortly after sunset. A few reports of hail and gusty winds are possible with these scattered storms before they weaken as they approach the Grand Strand.
An intense squall line of damaging thunderstorms is widely anticipated to move through Tennessee late this evening, accelerating toward the Upstate between 3 and 6 AM Thursday morning. The line of storms is expected to weaken somewhat as it approaches the Upstate, but it is unclear how quickly they will weaken. Residents should be aware of the possibility for damaging gusts with this fast-moving line prior to sunrise, particularly if the storms do not weaken as fast as some model simulations are indicating.
Provided this line of severe thunderstorms holds together, it could reach the Midlands between 6 and 8 AM, followed by the Pee Dee, Grand Strand, and Lowcountry regions between 8 and 11 AM. The risk of damaging wind gusts is likely to be lower closer to the coast, but minor damage can not be ruled out. For this reason, the Storm Prediction Center has placed the Upstate in a "slight risk" (level 2 out of 5) and much of the rest of the state in a "marginal risk" (level 1 out of 5) for severe thunderstorms.
High pressure is expected to approach South Carolina by the end of the week, resulting in a couple of tranquil days starting Thursday afternoon and lasting through Saturday. A large and strong storm is then forecast to take shape in the Southern Plains late this weekend. The Storm Prediction Center has outlined a risk area for severe thunderstorms on Sunday and Sunday night for Georgia and Alabama. Latest computer model simulations suggest this threat could also extend into South Carolina, either Sunday or Monday, and residents should monitor forecasts for changes this holiday weekend.