LA Times: The most severe heat wave so far this year is bearing down in Southern California, with temperatures likely to top 120 degrees. So how hot will it get? Temperatures in downtown Los Angeles are expected to climb from the mid-80s Saturday to the mid-90s by Sunday, while triple-digit temperatures are on tap for the valleys. But it's Monday, the first day of summer, that is expected to be the hottest. The looming heat has prompted the National Weather Service to issue excessive-heat watches for L.A.,...