Early-season heat wave brings scorching temperatures to Eastern U.S.

An intense and nearly historic weather pattern is cooking much of America under a dangerous heat dome this week with triple-digit temperatures in places that haven't been so hot in more than a decade.

The heat wave is hitting cities like Boston, New York, and Philadelphia early in the summer, trapping hot air from the Southwest. The dome of high pressure is making for a 'near historic' heat wave, likely peaking for Northeastern cities on Tuesday.

A heat dome occurs when a large area of high pressure traps heat and humidity, leading to a persistence of unusually hot temperatures.

Nearly three-quarters of the country's population will experience temperatures of 90 degrees Fahrenheit or higher on Monday, with 33 million people feeling blistering 100-degree heat on Tuesday. The highest level of heat risk is seen in swaths from Chicago to Pittsburgh and North Carolina to New York.

The heat is part of Earth's long-term warming, with summers in the United States now 2.4 degrees hotter than 50 years ago. Human-caused climate change has made this heat wave three times more likely.

Key question is how much humidity will add to the discomfort and danger of the heat. Forecasting dry air may make it more comfortable, while others expect sticky, humid conditions.

If this heat were later in the summer, it might not be as dangerous, but coming within days of the solstice, it will be a shock to the system.

According to the source: NPR.