NEW : No break from the heat week 's end , says The National Weather Service . High temperatures in America 's Plains States are expected to rival those in Death Valley again Monday , according to the National Weather Service , which predicts a heat wave to roast the county 's midsection for yet another day as it spreads to the east . the National Weather Service declared excessive heat warnings Sunday for several thousand states . High humidity has driven up heat indices , making it feel as hot as 126 degrees . The extreme heat is forecast to move east by Monday , affecting the East Coast .
NEW : No break from the heat week 's end , says The National Weather Service . the National Weather Service declared excessive heat warnings Sunday for several thousand states . High humidity has driven up heat indices , making it feel as hot as 126 degrees . The extreme heat is forecast to move east by Monday , affecting the East Coast .