A high heat index, driven by humidity, is forecasted for Columbia on May 16, posing overheating risks to outdoor laborers.

COLUMBIA — High heat and humidity are forecasted to combine tomorrow to bring the Midlands' first day of extreme heat this year, according to the National Weather Service's Columbia office.

"The combination of copious low-level moisture and well-above-normal temperatures is expected to create intense heat on Friday afternoon," the Columbia outpost of the National Weather Service shared May 15.

A high pressure system in the upper atmosphere will be over Columbia tomorrow around daybreak, promoting a higher heat index, or "feels like" temperature, according to Steve LaVoie, a forecaster with Columbia NWS.

Heat and humidity could drive the "feels like" temperature in the Midlands above 100 degrees Friday, May 16.

Humid air from the southwest, combined with a scorching sun and the abundance of moisture in the ground from recent rains, will combine to drive the heat index over 100 degrees, prompting safety warnings from the NWS, especially for people who spend a lot of time outdoors.

May 16 will be "the hottest of the next few days," LaVoie said. Actual temperatures are expected to peak at 92 degrees, according to the NWS.

Temperatures are forecasted to dip into the high-80s through the weekend, with a slight chance for afternoon thunderstorms on May 17, according to the NWS.

LaVoie said the forecast of 100-plus heat index is "slightly above average" from temperatures around this time of year, but nothing abnormal for the famously hot city. He added that the end of May is when summer temperatures typically start for the Midlands.

The muggy heat comes on the heels of more than 10 days of heavy rain, when much of the Midlands was under a flood advisory.

The Midlands has seen more than 4 inches of rain over the past seven days, according to U.S. Geological Survey rain gauges. Other parts of the state saw even higher amounts of rainfall, with Allendale measuring more than 9 inches of rain since May 8, according to USGS.