The National Weather Service has issued a heat advisory for much of Maryland from 1 p.m. until 8 p.m. Sunday. Additionally, Baltimore City health officials have issued a Code Red Heat Advisory for Saturday and Sunday with an expected heat index topping 100 degrees. Baltimore City Health Commissioner Dr. Leana Wen is encouraging people to take precautions when outdoors. "Heat is one of the leading killers for weather-related emergencies. It's really important to stay indoors when possible, drink plenty of fluids, avoid alcohol and don't leave kids and pets in your cars," Wen said.