Arielle Kaplan was trying to temper the heat and keep cool with her parasol as she waited to be part of a Freedom Trail Tour on Thursday. Boston’s high temperature on Thursday was 94 degrees, recorded at 3:22 p.m., according to Frank Nocera, a meteorologist with the National Weather Service. Friday’s forecast calls for a couple of showers and a heavy thunderstorm with the possibility of flash flooding. The humidity will decrease later in the day. Full report, C8