An exceptional heat wave is set to engulf the Midwest, Northeast, and Mid-Atlantic regions, bringing with it scorching temperatures and dangerous levels of humidity. The soaring heat indexes, reaching over 100 degrees, will stretch from the Gulf Coast all the way to Nova Scotia, putting vulnerable populations at risk.

The National Weather Service has issued warnings of a prolonged period of dangerously hot conditions, emphasizing the increased risk of heat-related illnesses during extreme heat and high humidity events. It is particularly concerning for those who work or engage in outdoor activities.

The oppressive heat has already begun to build across the Midwest and South, with cities like Chicago and Atlanta expected to reach highs in the mid-90s on Sunday. Little Rock in Arkansas is forecasted to hit 96 degrees, while St. Louis could spike to 98. However, these temperatures are only a preview of what is to come.

As the workweek progresses, temperatures in major cities such as Boston, Pittsburgh, and Washington D.C. could flirt with the 100-degree mark. Heat index values, taking into account the stifling humidity, are expected to easily surpass 100 degrees for several consecutive days. Unprecedented heat is anticipated in southeastern Canada and northern New England, with temperatures surpassing all-time records by 15 to 25 degrees.

Forecasters are predicting record-breaking temperatures in some unlikely places. Fort Kent, one of the northernmost cities in Maine, near the Canadian border, is expected to swelter at 101 degrees on Wednesday. Caribou, Maine, may surge to 99 degrees, surpassing its all-time record of 96 degrees. The Weather Service office in Caribou is even considering issuing its first excessive heat watch, signaling that heat index values could reach 105 degrees for two consecutive days with minimal overnight relief.

Excessive heat warnings already blanket states such as Ohio, Michigan, West Virginia, Indiana, and parts of Pennsylvania due to the anticipated intensification of the heat starting from Monday. Watches for excessive heat have also been issued in the Connecticut River and Merrimack Valleys in southern New England, with further upgrades expected as the heatwave escalates.

The upcoming long-duration heat wave is expected to expand and intensify throughout the week, culminating in the hottest 3-day stretch for some in 30 years, according to the Weather Service office in Burlington, Vermont. By Saturday, the most intense heat is predicted for the St. Louis area, parts of the Midwest, and the southern New England region, while the Mid-Atlantic, including Washington D.C., may see temperatures hitting 100 degrees for the first time since 2016.

The cause of this extraordinary heat wave is a massive heat dome, or ridge of high pressure, that is stagnating over the northern U.S. This heat dome acts as a force field in the atmosphere, deflecting inclement weather and creating hot and cloud-free conditions, allowing for even more dramatic heating.

Scientists have highlighted the link between human-induced climate change and the increasing frequency, intensity, and duration of heat events like this one. Heat domes, such as the one currently forming, are projected to become more frequent, stronger, and more expansive as the Earth's climate continues to warm.

As the heatwave approaches, authorities are urging the public to take precautions and stay hydrated. Vulnerable populations, especially those without access to effective cooling, are advised to seek relief in air-conditioned spaces. It is crucial to prioritize safety and take necessary measures to stay cool during this record-breaking heatwave.