South Carolinians can expect actual daytime temperatures to climb well into the upper 90s and low 100s through today and Sunday. However, the real danger stems from the oppressive humidity, which will drive "feels-like" heat index values well into the triple digits statewide:
The Lowcountry and the Coast: Is in the bullseye for the most extreme conditions.
Places like Beaufort and Charleston are under extreme heat alerts, with heat index values projected to peak between 115°F and 118°F. This is more than dangerous, its deadly. Limit time spent outdoors.
The Midlands and the Pee Dee: The Columbia area expect peak heat index values to touch 110°F.
The Upstate and Piedmont: Even the typically cooler northern counties are under a Heat Advisory, with feels-like temperatures hovering between 106°F and 109°F.
Why Is It So Hot?
According to South Carolina ETV and Public Radio Chief Meteorologist Tim Miller, the state is sitting under an intense upper-level high-pressure ridge parked to our west. This system acts like a giant "heat dome," trapping a thick blanket of humid, tropical air directly over the state.
Because high pressure compresses and warms the air below it, daytime cooling is stifled and heat builds up continuously day after day.
Afternoon Thunderstorm Risk
The ridge of high pressure will flatten out over the weekend, we’ll still have the extreme heat and abundant moisture, however the flatten ridge will allow for a better chance of afternoon thunderstorms. The Storm Prediction Center has placed parts of northern South Carolina — including Greenville, Spartanburg, and Rock Hill — under a Level 2 out of 5 "Slight Risk" for severe thunderstorms on Saturday. The rest of the state under a Level 1 "Marginal Risk".
While these storms will provide brief, late-day cooling relief, any cell that develops could rapidly turn severe. The main threats include:
Damaging wind gusts
Frequent, dangerous cloud-to-ground lightning
Torrential downpours leading to localized flash flooding
Heat Safety Guidelines
Extreme heat causes more annual weather-related fatalities in the United States than hurricanes, tornadoes, or floods. To protect yourself and your family, emergency officials recommend following these crucial steps:
Hydrate Constantly: Drink plenty of water and replenish electrolytes. Do not wait until you feel thirsty.
Time it Right: Shift strenuous outdoor activities or exercises to the early morning or late evening. Avoid the sun during peak heating hours from 11:00 a.m. to 8:00 p.m.
Stay Indoors: Remain in air-conditioned environments whenever possible
Dress Light: Wear lightweight, loose-fitting, and light-colored clothing
Look Before You Lock: Never leave a child, disabled person, or pet inside a parked vehicle. Interior car temperatures can quickly become fatal
Protect Pets: Ensure pets have shaded areas, cool surfaces, and fresh water to avoid veterinary heat stress.