National Weather Service warns heat index could reach 115F as extreme heat grips midwest, Ohio valley and east coastSign up for the Breaking News US newsletter emailA “prolonged, dangerous heatwave” is expected to intensify across parts of the central and eastern United States over the next few days and into the holiday weekend, bringing record-breaking temperatures, humidity, and dangerous conditions to millions of Americans.The National Weather Service (NWS) warned on Thursday that temperatures between 95F (35C) and 105F (40.5C), combined with high humidity, will push heat index values across parts of the region to between 100F (37.7C) and 115F (46.1C). Continue reading...