 starting at noon today until 8 p.m. tonight. According to the National Weather Service, a combination of high heat and humidity are expected to drive the heat index up to 107 degrees. Officials say that as the heat wave continues, extending the cold red in parts of Baltimore City is vital for the safety and well-being of residents. Meanwhile, residents in Baltimore County neighborhood are on edge after a grandmother and her granddaughter were found dead inside of their Middle River home.