Dangerous Heat.  Excessive Heat Warning.  Details here  With northwest winds and searing sun the temperatures in most areas in and around DC are likely to be 100º or higher this afternoon.  The Heat Index this afternoon will be 105º to 115º which is dangerous heat especially for the elderly and very young.  Best, if possible, just to stay inside and in air conditioning.  This afternoon and evening there is a risk of some thunderstorms which may bring some brief relief, but also just add to humidity we will continue to have over the weekend.  Clusters of thunderstorms will be forming along a weather boundary to our north and some of these will move across the region again late tonight or tomorrow but just not possible to say exactly where and when.  Today will probably be the hottest of the next 3 but the weekend will still feel about 105º  Not as hot next week