A heat dome that has been parked over the southwestern United States throughout most of July is starting to expand eastward, and millions of people in the mid-Atlantic will soon feel the effects. The temperatures in Washington, D.C., and Baltimore are predicted to top out around 100 degrees Fahrenheit at the end of the week, the hottest it has been in both cities in years. "It has not yet reached 100 in either city this year," AccuWeather Senior Meteorologist Bill Deger said. "In fact, it has no