NEW : No break from the heat Monday , says the National Weather Service . In Iowa , for instance , he noted that the impact of mid-90s temperatures have been compounded by relatively high dew points in the upper 70s and low 80s . The National Weather Service declared excessive heat warnings Sunday for 14 states . A man walks through a flooded street in downtown Houston on August 29. The extreme heat is forecast to move east by week 's end , affecting the East Coast .
NEW : No break from the heat Monday , says the National Weather Service . The National Weather Service declared excessive heat warnings Sunday for 14 states . A man walks through a flooded street in downtown Houston on August 29. The extreme heat is forecast to move east by week 's end , affecting the East Coast .