Big Hot Bubble Is Moving East: A Kid-Friendly Guide to the Heat Dome

What Is Happening?

Imagine a giant invisible lid of hot air (called a heat dome) sitting over the United States. This lid recently broke all-time heat records in the northern Rockies and Northern Plains (big mountainous and flat areas in the northern US). Now, that hot, sticky air is sliding over the Midwest and East.

• The heat dome is spreading super hot temperatures and humidity.
• Over the next few days, many daily record highs (the hottest a place has ever been on that date) might fall from the Midwest to the Northeast.

Important Point: A heat dome is like a huge trap of hot air. Want to know more? Check out What is a heat dome?

Heat Alerts

The map below shows where the National Weather Service (the people who watch the weather for the US) has put up heat alerts. These alerts stretch from the Northern Plains all the way to New England and the mid-Atlantic states.

There are two main kinds of alerts you should know:

• Extreme heat warnings: Given when people are very likely to get sick from the heat, like heat exhaustion (feeling super tired and weak from heat) and heat stroke (a dangerous overheating of the body).
• Heat advisories: Less serious than warnings but still say "be careful, it’s hot!"

If a warning is issued, here is what to do:

1. Plan to stop all big outdoor activities (like sports or yard work).
2. If you don’t have air conditioning, find the nearest cooling shelter (a place with AC to stay safe).
3. Or talk to family or friends nearby who have AC and see if you can stay with them.

Important Point: Extreme heat warnings mean getting sick from heat is almost certain. Do not ignore them!

Want 5 tips to stay safe? See 5 things to know to stay safe in a heat wave.

Midwest and Northeast Heat Forecast

The hot, humid air will very slowly fade in the Midwest and East through the rest of the week, but it will still be warm.

• Many places will hit the 90s°F (about 32–37°C) in the afternoons.
• A few spots in the Midwest and East Coast could get close to 100°F (about 38°C) on Wednesday.
• Wednesday daily record highs could be set in parts of the Northeast: New England, upstate New York, and the mid-Atlantic.
• On Wednesday, Baltimore, Philadelphia, and Atlantic City could all reach 100°F — that would be a new daily record for each.
• New York City could also go over 100°F and set a record.
• Even at night, big cities may only cool to the middle or upper 70s°F (around 24–26°C), so no real break from the heat.

When Will Relief Arrive?

Good news — help is on the way!

1. A fairly strong cold front (a line of cooler air) will drop from eastern Canada into the northern US states on Wednesday.
2. A second cold front will follow later in the week.
3. By Wednesday, the northern Great Lakes and northern New England get some relief.
4. From Friday into the weekend, more of the Midwest and Northeast cool down from north to south.

Important Point: America’s deadliest weather is heat — not tornadoes or hurricanes. Read more: America’s deadliest weather is heat

See the 10-day US forecast highs and lows.

West Heat Forecast

In the Rockies and Northern Plains, the heat won’t change much this week.

• We won’t see the all-time record heat from last Sunday again.
• But highs in the 90s°F will be common in lower areas of the Northern Plains and Rockies most of the week.

Historic Heat Records Were Tied or Broken

This heat wave already made history on Sunday in four states:

• Billings, Montana (biggest city in MT) hit 111°F — old record was 108°F.
• Miles City, Montana hit 115°F — old record 111°F, just 2°F shy of the state record and the same as Death Valley’s Stovepipe Wells that day.
• Salt Lake City hit 109°F — hottest in over 150 years.
• Sheridan, Wyoming hit 109°F and Idaho Falls, Idaho hit 103°F — both broke all-time records.

See current temperature maps and heat index maps.

Summary

A giant heat dome broke records in the northern Rockies and Plains and is now bringing hot, humid air to the Midwest and East. Many cities could hit 100°F and set records on Wednesday. Heat alerts are active, so stay inside or find AC. Cooler air arrives late week from the north. The West stays hot but not record-breaking. Heat is the deadliest US weather, so take it seriously.

FAQ

What is a heat dome?
A heat dome is like a big lid of hot air stuck over an area, trapping heat and making it super hot for days.

What should I do if an extreme heat warning is issued?
Stop outdoor activities, and if you lack AC, go to a cooling shelter or stay with someone who has AC.

When will the East get relief from the heat?
A cold front brings relief to the northern areas by Wednesday, then more of the Midwest and Northeast from Friday to the weekend.

Why is heat so dangerous?
Heat causes more deaths in the US than tornadoes or hurricanes because it can quietly make people very sick.

Did any cities break all-time records?
Yes! Billings and Miles City in Montana, Salt Lake City, Sheridan in Wyoming, and Idaho Falls all broke records on Sunday.