Gradually moving from the Midwest and seeping into the East, the deadly US heatwave is pushing temperatures above 100F with a forecast to get even hotter during the weekend.

The heat, combined with rocketing levels of humidity has been cause for the National Weather Service to issue hot weather warnings across the country. The heat has already caused 22 deaths.

New Yorkers have complained about feeling smothered by the humidity. It's like being in a sauna which your average person can't even stay in for more than 5 mins, Management Consultant, Laura Hartley, told the International Business Times.

A Halal food street vendor on 10th Avenue and the corner of 37th street in Manhattan said he would only work until noon to avoid melting into the ground.

Just as New Yorkers looked to escape the heat at the Hudson River, they were thwarted by public health officials who warned people of direct contact with the water due to a massive sewage release. A fire that caused a New York City wastewater treatment plant to shut down.

According to Meteorologists the high temperatures result from a Dome of high pressure from the atmosphere, the BBC reported.

This is an exceptionally strong ridge of high pressure that really has an exceptional scope and duration, Eli Jacks, a meteorologist with the National Weather Service, told the BBC.

The air is sinking; as it sinks it compresses and gets warmer. It also dries out, so few clouds form to block the high early-summer sun, he said.

The combination of high heat and high humidity make it hard for the human body to cool itself - because sweat does not evaporate efficiently, he added.

As the heat peaks officials have warned of more deaths, and advised for people to keep indoors and hydrated.