 D.C. Mayor Muriel Bowser has extended the district's heat emergency through Thursday. Fairfax County Public Schools have canceled all outdoor activities today. We have your full forecast in minutes right here on WTOP. Most medical students at Johns Hopkins University in Baltimore will no longer pay tuition. Starting in the fall, it's all thanks to a billion-dollar gift from businessman, philanthropist, and former New York Mayor Mike Bloomberg. WTOP's Dick Uliano reports the extraordinary gift could impact students and patients across the country.