A dangerous, widespread heat wave is predicted to unfold for millions across the Northeast and Midwest next week with AccuWeather RealFeel® Temperatures even approaching the 100-degree Fahrenheit mark in some cities. "The increased demand for cooling is going to be a problem here. This could have some impacts on the power grid," AccuWeather Chief Video Meteorologist Bernie Rayno said. In the Midwest and Northeast, a heat wave is considered to be at least three days with a high temperature of at least 90 degrees, and for some areas, the mercury will exceed that benchmark for most or all of the...