A heat dome -a high-pressure system that traps hot air- is expanding from the Great Plains into the Northeastern United States, already impacting 170-200 million people. Forecasts call for temperatures near 105°F (40°C) in the Midwest and highs around 100°F (37°C) in the Northeast, with nighttime lows staying above 75°F (24°C).

Meteorological agencies, including NOAA and the National Weather Service (NWS), have issued extreme heat alerts and heat dome warnings starting Friday, with potential relief not expected until midweek. More than 35 million people may experience temperatures exceeding 100°F (38°C).

Health Risks and Recommendations

• The high heat index (feels-like temperature over 105°F/40°C) increases the risk of heatstroke, exhaustion, and cardiovascular stress.

• Sweltering nighttime temperatures, with minimal cooling, elevate public health concerns.

• Cities are activating cooling centers and urging residents to check on vulnerable groups, including the elderly, people without air conditioning, and outdoor workers.

Medical professionals advise limiting physical activity during peak heat hours, staying hydrated, and recognizing symptoms of fatigue or dizziness. Heatstroke can develop rapidly, especially in the elderly and children. Public health experts warn that internal body temperature can exceed 104°F (40°C) without timely intervention.

Emergency services have reported a rise in heat-related calls. In urban areas with little vegetation and large expanses of asphalt, the "urban heat island" effect amplifies conditions, causing temperatures to climb 5°F (3°C) higher than in rural zones.

Infrastructure Impact

The surge in air conditioning use is straining power grids, with some areas setting historical demand records. Utility companies are asking consumers to reduce usage during peak hours to prevent outages. Several municipalities have already enacted electricity restrictions during certain times of the day.

Construction, agriculture, and public service workers are especially exposed. Labor organizations are calling for increased rest breaks, access to shade and water, and workday adjustments to avoid critical heat periods.

Transportation systems are also under alert. Extreme heat can warp rail lines, soften asphalt, and even cause flight disruptions due to thermal limits on runways. Some airports have already reported delays due to the harsh conditions.

Climate Context and Projections

This event aligns with a growing pattern of increasingly extreme summers across the U.S. Recent scientific studies warn that such heatwaves will become more frequent, longer-lasting, and more intense due to climate change. Data from the past 20 years show a consistent rise in both the duration and maximum temperatures reached during these episodes.

Climate researchers indicate that the heat dome phenomenon is tied to shifts in the jet stream, which normally governs Northern Hemisphere weather. When the jet stream weakens, it can become stagnant, allowing stationary high-pressure systems to form and trigger prolonged periods of extreme heat.

Forecast models suggest that unless greenhouse gas emissions are curbed, events like the 2025 heat wave could become the norm for future summers. This would not only jeopardize public health but also impact crop yields, air quality, and the economic stability of both rural and urban areas.