At the beginning of the week, we told readers the dog days of summer have finally arrived with above-average temperatures for most of the country. 

By late Thursday, watch/warning/advisory alerts for dangerous heat extended to nearly 200 million Americans as multiple heat domes scorch the Pacific Northwest, Central states, and East Coast.

"Dangerous heat and humidity in the Northwest, Northeast, and central portions of the CONUS have prompted Excessive Heat Warnings and Heat Advisories. Severe thunderstorms will impact the areas from the Midwest into the Great Lakes through Thursday," the National Weather Service (NWS) wrote on its website.