#Heatwave will hit about two-thirds of USA into the weekend, impacting tens of millions of people with max heat index well above 100°F (38°C) in places like Dallas, Chicago, Detroit, Washington D.C., NYC and Boston, per @NWS. 20 to 30 record highs are possible. pic.twitter.com/Y4pwciIYzQ

— WMO | OMM (@WMO) July 18, 2019