Update Tuesday 2:00 p.m. ET:
A Severe Thunderstorm Watch has been issued for eastern South Carolina until 10 p.m. A line of strong to severe thunderstorms are developing along and southeast of a cold front moving south towards the Lowcountry. Scattered damaging wind gusts up to 70 mph and a tornado or two are possible.
Update Tuesday 11:30 a.m. ET:
The Storm Prediction Center has upgraded the risk for severe thunderstorms in the Pee Dee region this afternoon. The primary risk for some of the storms is stronger wind gusts that may produce scattered wind damage. The most likely time for the storms to occur is between 5 and 10 p.m. over the Pee Dee region.
A Marginal Risk of severe weather continues for the Midlands to the Lowcountry. The storms will move through the Midlands between 1 and 5 p.m. and the Lowcountry between 6 p.m. and midnight. Some storms could contain a brief damaging wind gust in these areas.
Tropical Depression Three has dissipated as of 11 a.m. about 60 miles east-southeast of Daytona Beach, Florida. The cold front that is bringing the heavy rain and thunderstorms to the state has caused caused the depression to weaken and will steer the remnants away from South Carolina.
Original post from Monday, July 22
After days of temperatures in the upper 90s and heat indices in the triple digits, much cooler weather is on the way to the Palmetto State. It will come in the form of a strong cold front that is on track to sweep across most of South Carolina Tuesday. The front will bring an end to the heat wave, but there will be a price to pay.
The front will bring the threat for excessive rainfall on Tuesday. The highest chance of heavy rain will be in the mountains and Upstate late Tuesday morning and early afternoon. The computer models forecast this heavy rain to spread eastward into the Midlands late Tuesday afternoon, and then to the Pee Dee and Low Country Tuesday night. For this reason, NOAA’s Weather Prediction Center has placed most of the state in a “slight risk” for flash flooding. The center says an average of 1.5 to 2.5 inches of rain is likely, along with locally higher amounts. They added that this rain may cause areas of flash flooding, primarily in urban areas.
Most of South Carolina, except for the Blue Ridge Mountains, is under a “marginal risk” of severe thunderstorms on Tuesday. NOAA’s Storm Prediction Center is forecasting numerous thunderstorms and its early afternoon forecast is calling for a few locally damaging winds with a few of the strongest cells. However, atmospheric ingredients are not favorable for widespread reports of damaging thunderstorms over the state.
Calmer weather and a 5 to 10 degree drop in temperatures are expected behind the front. The National Weather Service is forecasting highs in the lower to mid 80s over much of the state Wednesday and Thursday. The dew point temperature, which is a measure of how dry the air is, is expected to plunge into the 50s. This drier air will make a huge difference in how the air feels, particularly across the Midlands and Upstate.
The drier air may take longer to reach the Pee Dee and Low Country, including Myrtle Beach and Charleston. Still, drier air is expected to gradually filter in late Wednesday or Thursday, providing mid-summer heat relief for many.