Extreme heat and storm risk mar July 4th celebrations across parts of the U.S.

An extreme heatwave is gripping the United States, impacting July 4th Independence Day festivities with forecasts of record-breaking temperatures and suffocating humidity across the Northeast and Mid-Atlantic states. The National Weather Service warns of dangerous conditions persisting through the weekend.

Severe thunderstorms are also a significant threat, particularly in the Mid-Atlantic region. The Storm Prediction Center has issued alerts for frequent lightning, severe wind gusts, hail, and the potential for tornadoes, especially affecting the Allegheny Plateau and surrounding areas. These storms are expected to impact the Central and Southern High Plains into Sunday morning.

Major urban centers are bearing the brunt of the heat. Washington D.C. recorded its highest temperature for July 4th at 38.9 degrees Celsius (102°F), leading to the suspension of National Mall events and delays for Washington Monument celebrations. In New York, temperatures near 38 degrees Celsius, amplified by humidity, coincide with a major naval and air exhibition and Macy's fireworks display. Philadelphia is also experiencing similar high temperatures, prompting cancellations of street parties and adjustments to fan zones for the World Cup viewing.

Authorities in these cities are urging residents to stay hydrated and take precautions. Public cooling centers have been opened as the electrical grid strains under the high demand for air conditioning, causing localized outages. In New Jersey, approximately 180,000 homes were without power due to severe storms.