Millions of Americans prepared to sweat through yet another scorching day, with the potential for rolling storms to bring relief from high temperatures for at least some. Floodwaters inundated parts of the Midwest, including a town in Iowa evacuated after being submerged up to the rooftops. From the mid-Atlantic to Maine, across much of the Midwest and throughout inland California, public officials cautioned residents sweating through the heat and humidity. The National Weather Service warned of the potential for rare tornadoes in the Northeast later Sunday.
