What Is a Heat Dome?
Heat domes occur when strong high-pressure systems trap hot air over land, acting like a lid and intensifying extreme heat. This phenomenon stops heat from escaping, resulting in dangerously high temperatures that can last for days or even weeks.
The simplest explanation is that heat is trapped and gets hotter the longer it stays trapped.
The Role of Jet Streams
Heat domes and jet stream dynamics are closely connected. The jet stream, a fast ribbon of air high in the sky, often helps regulate temperature by moving air masses about.
But when the jet stream pauses or ripples, warm air is trapped and ridges—areas of high pressure—are created. This is happening right now in parts of the eastern United States and Europe.
Impact on the United States
As of June 26, 2025, heat alerts are in place for 150 million Americans.The National Weather Service has issued a warning of “extremely dangerous heat” after temperatures in the Ohio Valley and East Coast topped 95°F.
Heat domes also strain electrical systems, increase the risk of heatstroke, and may result in more hospitalizations, especially for individuals with underlying medical conditions, the elderly, and young children.
Heat domes and climate change
Domes are being exacerbated by climate change, according to scientists. Studies show that the incidence, severity, and duration of these events are rising.
The past decade has been the warmest on record since 1850, according to NOAA. Extreme heat occurrences are becoming the new normal as a result of global warming.
Relief Is Coming—But Not for Everyone
Some cooling relief is expected later this week for parts of the Midwest and East Coast. However, humidity and lingering high temperatures will remain an issue.
Meanwhile, Europe is facing its own heat dome, with parts of France forecast to hit triple digits.
Source: NBC News