Lincoln County and much of Mississippi are under a “significant risk” of heat stress and stroke, according to the National Weather Service in Jackson.

Saturday air temperatures are expected to reach the upper 90s to 100 degrees Fahrenheit, with a peak heat index of up to 115 degrees.

The heat index is a measure of how hot it really feels when relative humidity is factored in with the actual air temperature.

Heat stroke is increasingly likely to occur with prolonged outdoor activity under a significant heat stress risk. Residents are urged to stay hydrated and avoid spending long periods of time outdoors during this prolonged heat wave.

The area under the significant risk includes Lincoln, Lawrence, Franklin, Copiah and Jefferson counties, extending into the central portion of the state and Louisiana.

An extreme risk, where heat stroke is imminent with prolonged outdoor activity, exists across much of the Mississippi River Delta.

Heat stroke will be a significant concern with prolonged outdoor activity, NWS warns.

The National Weather Service suggests drinking plenty of water even if not thirsty; wearing sunscreen; wearing lightweight, loose-fitting and light-colored clothing; and only working outdoors in the early or late day, and only if necessary.

The Midcontinent Independent System Operator’s region has notified utility companies to prepare for emergency conditions, according to Entergy reports, though a power shortage is not expected.

Extreme heat conditions may lead to increased power usage for air conditioning, leading to generating stations tripping, however. Residents are therefore asked to use appliances only as necessary throughout the heat warning period, such as using a microwave instead of an oven or stove, washing clothes only in the early morning or late evening, turning off the heat dry setting on dishwashers and only drying clothes overnight.

Cool showers or baths are recommended to help cool down. Check on friends and neighbors, especially those with known health problems or who are elderly. Never leave children or pets in vehicles — temperatures in a locked vehicle can reach temps higher than 140 degrees within minutes, according to weather.gov.