Washington, D.C. - at 10 a.m. with a temperature of 90 - is hotter than any city on the Weather Channel’s national weather map. Its closest competition? Chicago at 89.
Even after the Southwest has a chance to catch up to us this afternoon, only Death Valley will probably top D.C.’s high temperature for the day. A few spots in the Plains and Midwest will have comparable heat.
The cause? The sprawling heat dome from the Plains to the East Coast. The heat over D.C. is being maximized due to winds from the west over the Appalachians which then sinks and compresses on the downwind side, causing somewhat of a local heat maximum.