Memorial Day marks the unofficial start to summer and sweltering heat will have a firm grip on the Southeast through and beyond the extended holiday weekend. While there will be little rain to aid firefights and to impact holiday festivities, residents will have to take the necessary precautions to avoid heat-related illnesses. Temperatures will soar into the middle and upper 90s through Memorial Day in Montgomery, Alabama; Atlanta; and Tallahassee and Tampa, Florida. Highs near or above the century mark will continue to bake Columbia, South Carolina; Augusta and Savannah, Georgia; and Jacksonville, Florida.