Americans in much of the country will be getting a slight break from the oppressive heat on Sunday, one day after temperatures rose to above 100 degrees from the central states to the mid-Atlantic. Yet for many, the cooler temperatures won't exactly be comfortable, falling only into the 90s.

Cooler air is sweeping southward in the eastern half of the country, bringing down some temperatures by 15 or more degrees from Saturday's highs. In St. Louis, the 13-degree drop from Saturday's high still will leave residents baking in 93-degree weather — the high Saturday was a record 106.

Temperatures in Philadelphia, Washington, and Indianapolis will fall to the low 90s or upper 80s on Sunday after crossing the 100 mark on Saturday. Residents in Louisville, Ky., can expect a high of 95, one day after 105-degree temperatures.

For many areas, the cooler temperatures were ushered in by thunderstorms that knocked out power to thousands.