St. Louis, Missouri — Extreme heat warnings are posted across the central U.S. Temperatures feel well over 100 degrees. Public health officials are warning people to heed their heat warnings.

In Madison, Wisconsin, volunteers are going door to door checking on the elderly. St. Louis is in the excessive heat danger zone. Prolonged exposure to the heat and humidity could be deadly for the most vulnerable.

The National Weather Service's heat warnings cover most of Missouri and eight other states. This is the first scorching heat wave the country has seen this summer.

"What we're currently seeing is that there are twice as many record highs on any given day than there are record lows. And this is really significant, so we will continue to see record breaking temperatures as we go on into the future," said Michael Wysession, a professor of Earth and Planetary Sciences at Washington University.

The dome of heat will head east by the weekend. Portland, Maine will feel like 98 degrees on Saturday. New York City will feel like 112 and in the nation's capitol it will feel like 107 degrees.

This heatwave is expected to last through Sunday. According to a recent climate study, the number of days where the U.S. experiences heat that feels at least 100 degrees, will double from 14 to 36 by 2050.