A massive "mega heat dome" is spreading across the United States, placing 35 states and nearly 200 million people under dangerous heat

Are you one of the millions of Americans trapped in a 'heat dome?'

Track extreme heat alerts with this interactive map
By Casey MillerJuly 1, 20263:12 AM MST Updated 2 hours ago

A hot and dry wave of high pressure, dubbed a "heat dome" by weather forecasters, is expected to raise temperatures to dangerous levels across the Eastern half of the United States over the Independence Day weekend.
Explore the weather system's size and scale using this interactive map, which plots the areas covered by the latest watches, warnings and advisories issued by the U.S. National Weather Service.

What are heat alerts?

The National Weather Service issues its warnings in three escalating tiers

Extreme Heat Warning

The highest tier — issued when extremely dangerous heat is happening or imminent.

Extreme Heat Watch

Flags likely danger over the next two to three days when intensity is still uncertain.

Heat Advisory

The lowest tier — elevated but not extreme heat is possible.

Extreme heat will also greet fans and players this week at the World Cup, as the heat dome settles over the central and eastern United States - plus parts of Canada - as the knockout rounds progress

Editing by Ben Welsh; Watches, warnings and alerts are from the National Digital Forecast Database published by the US National Weather Service. Population estimates were calculated by crossreferencing the areas covered by alerts with the LandScan global dataset published by the Oak Ridge National Labratory. In cases where an area was covered by more than one alert, the population was allocated to the most severe tier.

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A massive "mega heat dome" is spreading across the United States, placing 35 states and nearly 200 million people under dangerous heat as forecasters warn of life-threatening conditions through the week.

The combined high-pressure systems are expected to push temperatures and humidity to extreme levels, with heat index values topping 105°F across parts of the Midwest, South, Mid-Atlantic, and Northeast. Major cities, including New York City, could approach 100°F, while warm overnight temperatures may offer little relief, increasing the risk of heat exhaustion and heat stroke.

Meteorologists are urging people to stay hydrated, avoid strenuous outdoor activity during peak afternoon hours, check on vulnerable family members and neighbors, and never leave children or pets inside parked vehicles.

#HeatDome #Heatwave #ExtremeHeat #WeatherAlert #USAWeather #Climate #Summer 

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