High temperatures in the low 90s will combine with high amounts of humidity to produce afternoon heat index values up to 108 in the Myrtle Beach area and 104 in Florence.

A heat index advisory index was issued by the National Weather Service and updated on Wednesday to include the beaches. The heat advisory includes Horry, Florence, Marion and Georgetown counties. The beach areas along the Grand Strand and coastal Brunswick County also are included.

The combination of high temperatures and humidity will create a situation in which heat illnesses such as heat exhaustion and worse yet, heat stroke, are possible.

The heat and humidity may cause heat stress during outdoor exertion or extended exposure.

If outdoors, drink plenty of fluids to stay well hydrated and wear lightweight and light-colored clothing. It is also recommended to take frequent rest breaks in shaded or an air-conditioned environment.

In addition, be sure to check on those who are most vulnerable to the heat such as young children and the elderly. Ensure all outdoor pets and livestock have access to fresh water and a well ventilated and shaded area during the hottest portions of the day. And never leave children or pets in a closed up vehicle, temperatures could reach 120 degrees in a manner of minutes.