Context:

A formidable heat dome has enveloped the Eastern United States, bringing unprecedented temperatures to regions such as Boston, New York, and Philadelphia, with some areas experiencing their highest temperatures in over a decade. This early-summer heat wave is particularly dangerous because people have not acclimated to such intense heat, with temperatures reaching triple digits and affecting nearly three-quarters of the U.S. population. The heat dome, characterized by a high-pressure system trapping heat and humidity from the Southwest, has already set records for atmospheric pressure strength. The combination of intense heat and high humidity levels, exacerbated by recent wet conditions, is making the heat feel even more oppressive, with heat indices reaching dangerous levels. This event is a stark reminder of the long-term warming trends attributed to climate change, making such heat waves more frequent and intense than in the past.

Dive Deeper:

• The heat dome is a large area of high pressure in the upper atmosphere, trapping heat and humidity and causing prolonged heat waves that last three days or more. This particular heat dome is notable for its intensity, with pressure readings breaking records, contributing to a 'near historic' heat wave.

• Meteorologist Ryan Maue describes the heat dome's effect as similar to an air fryer, with cities like New York and Philadelphia experiencing temperatures they haven't seen since 2011 and 2012, respectively. The heat is particularly dangerous early in the summer when people are not yet acclimated to such extreme conditions.

• With temperatures expected to reach 100 degrees Fahrenheit or higher, nearly 245 million people are facing dangerous heat conditions, with 33 million experiencing particularly blistering temperatures. The heat is exacerbated by high humidity levels, which increase the perceived temperature and discomfort.

• Climate change has made such extreme heat events more likely, as summers in the U.S. are now 2.4 degrees Fahrenheit hotter than they were 50 years ago. The burning of fossil fuels has significantly contributed to this trend, as demonstrated by climate models comparing current conditions to a world without industrial greenhouse gases.

• Humidity plays a critical role in the oppressive nature of the heat, with dew points reaching tropical levels in the 70s and 80s. Meteorologists warn that the combination of high humidity and heat, especially early in the summer season, poses a significant health risk as the human body has not yet adapted to these conditions.