Today's advisory is from 11 a.m. to 9 p.m. Monday's heat index was five to 10 degrees lower locally, according to a special weather statement from the National Weather Service in West Columbia, S.C.
To combat the heat, experts recommend drinking plenty of fluids, staying in air-conditioned locales and checking on relatives and neighbors.
Those who work or spend time outside are advised to reschedule strenuous activities to the early morning or evening.
Richmond County sheriff's Maj. Richard Weaver said road patrol deputies typically get a break on their uniform requirements during extreme heat.
"We let them try to stay as cool as we can," he said.
The high Monday was 95 degrees. Temperatures will soar into the upper 90s, approaching 100, through midweek. Meteorologists are predicting at least a 20 percent chance of thunderstorms tonight, with the chances increasing every night throughout the remainder of the week.
Temperatures will dip into the lower 90s on Thursday. The cooling trend will continue Friday, with a chance the mercury won't push past 90.
While the temperatures probably won't break records in the low 100s, this week's heat is above normal, meteorologist Jim Kilmer said.