A man pours water on his head to cool off in Algiers during a heat wave
Some 80 million people are currently under a heat advisory AFP

A high-pressure weather system is predicted to bring potentially record-breaking temperatures to central and eastern parts of the U.S. this week, according to National Weather Service (NWS) forecasters.

The excessive heat threatens a large swath of the country with multiple days of dangerously high temperatures.

The heat wave coincides with the observance of Juneteenth on Wednesday. Traditionally celebrated with outdoor activities such as barbecues, the extreme heat poses a challenge for many, especially Black Americans in Texas, where the day holds significant cultural importance.

Currently, around 80 million people are under a heat advisory or warning, with temperatures expected to surpass 90 degrees Fahrenheit and potentially reach 100 degrees in some areas, Reuters reported.

This is approximately 20 degrees above the seasonal average, said meteorologist Andrew Orrison of the NWS.

Officials are advising the public to stay hydrated, limit strenuous outdoor activities, and wear lightweight clothing.

The heat index, which includes humidity effects, could make conditions feel even hotter, with parts of Indiana, Ohio, Michigan, and New England experiencing heat indices in the triple digits.

In response, New York City's emergency management and health departments issued a joint statement announcing the opening of cooling centers starting Tuesday.

They warned that high heat is a "silent killer," particularly dangerous for older adults, young children, people with chronic conditions, and pregnant women.

New York City, which typically experiences two heat waves each summer lasting around four days each, is now preparing for prolonged periods of excessive heat. Historically, the longest heat wave in the city lasted 12 days from August 24 to September 4 in 1953.

On average, the city records high temperatures of 90 degrees Fahrenheit or above 15 times each summer. However, climate projections suggest this number could soar to 69 by the 2050s, with heat waves lasting up to six days.

The concrete jungle, characterized by its towering buildings and extensive paved surfaces, heats more efficiently during the day due to the Urban Heat Island Effect.

Chicago has also announced the opening of cooling centers to help residents cope with the heat.

The NWS has warned against leaving children and pets unattended in cars, as the interior temperature can rise rapidly, leading to heatstroke.

Temperatures are expected to remain elevated until the weekend.

Climate change