Heat Wave: Weather Service Issues “Screaming Message”

By Tom Yulsman | June 29, 2013 12:17 am

An artist’s conception of a hypothetical dome of high pressure lodged in the middle layers of the atmosphere , which brings high temperatures to the surface. A similar dome of high pressure now sits over the a large portion of the western United States. (Image: National Weather Surface)

As a weather weenie, I actually click on the ‘forecast discussion’ link on National Weather Service pages so I can geek out on all the meteorological details behind a forecast. But in all the years I’ve been doing this (and there have been many), I’ve rarely seen language like this:


Source: National Weather Service

As I’m writing this, it is 8:15 p.m. in California, and near Furnace Creek in Death Valley National Park the temperature stands at 118 degrees F. That’s just four or five degrees down from today’s high temperature.  But it’s nothing compared to what may be coming.

Looking forward, it’s possible that the record for highest temperature ever reliably recorded on planet Earth could be tied or broken before this epic heat wave is all over. This has been reported widely, and one of the first to do so was my colleague Andrew Freedman over at Climate Central.

But what exactly is going on? Perhaps you’ve heard that the extreme high temperatures in the region are due to a dome or ridge of high pressure over the West. But what does that actually look like? The illustration at the top of this post gets at that question.

Keep in mind that the picture shows a hypothetical dome, not the real one causing all the trouble right now. And its position is shifted eastward.

Check out the excellent explanation of this phenomenon by the National Weather Service. Here’s a snippet:

Summertime weather patterns are generally slower to change than in winter. As a result, this mid-level high pressure also moves slowly. Under high pressure, the air subsides (sinks) toward the surface. This sinking air acts as a dome capping the atmosphere.

This cap helps to trap heat instead of allowing it to lift. Without the lift there is little or no convection and therefore little or no convective clouds (cumulus clouds) with minimal chances for rain. The end result is a continual build-up of heat at the surface that we experience as a heat wave.

The dome over the West is locked in place because of a giant kink in the jet stream:

A large kink in the jet stream across North America, shown by the dashed yellow lines and blue arrows, is helping to bottle up a dome of high pressure that’s causing dangerous heat in large portions of the West. The image shows the jet stream’s position as of 8:00 p.m. EDT on June 28. For an animation depicting the evolution of the jet stream over time, click here. (Image and animation: California Regional Weather Server.)

That kink is stuck in place for now, and it looks like it is going to remain that way for awhile. I’ll be watching to see whether this results in a new record for highest temperature ever recorded on Earth.


  • Buddy199

    As the Chinese and Indians are building one new coal plant a week, my using a cloth Whole Foods bag doesn’t seem to be making much difference.

    • ArchiesBoy

      Seems that way. But a beach is made up of individual grains of sand, and a human body is made up of individual cells. A cell is made up of molecules, and molecules are made up of atoms … It’s sort of in the area of The Theory of Large Numbers.

      • Buddy199

        ?? Specific point being?

        • ArchiesBoy

          Specific point: Your and everyone else’s Whole Food bags taken together make a difference.

          • http://PolyKhromeGames.blogspot.com/ Brian Lockett

            Forgive me if I’m mistaken here, but I think his point is that polluters outnumber people trying to do their own part by like a million to one. It might be noble, but noble doesn’t negate this reality that things are deteriorating faster than what’s being saved.

        • Isabel Herron

          just as Willie
          responded I’m shocked that a stay at home mom can make $9767 in 4 weeks on the
          internet. have you seen this link w­w­w.K­E­P­2.c­o­m

  • lesliel8

    This dome contributed to a nasty low being parked over the Rocky Mountains in southwestern Alberta, leading to worst-ever flooding in the Banff area, Calgary and points east.

  • Elle1980

    Meh, here in Quebec Canada, it’s raining almost non stop since the beginning of summer. I hope everythin will change for everybody soon !

    • http://PolyKhromeGames.blogspot.com/ Brian Lockett

      Yeah, here in upstate New York, it’s been nothing but heavy rain for the past few weeks. Here’s hoping the heat relents some for other places.

  • James Johnson

    Where is the dome? The article says the first figure is not intended to be accurate and the last figure is hard to interpret. The dome is caused by a “giant kink in the jet stream” but that does not make clear the spatial relationship of the kink to the dome.
    Where can I see a map of the extent of the heat wave?

  • Roger

    As interesting as this is, don’t you think that possibly it was just a typo for “streaming message”?



ImaGeo is a visual blog focusing on the intersection of imagery, imagination and Earth. It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.

About Tom Yulsman

Tom Yulsman is Director of the Center for Environmental Journalism and a Professor of Journalism at the University of Colorado, Boulder. He also continues to work as a science and environmental journalist with more than 30 years of experience producing content for major publications. His work has appeared in the New York Times, Washington Post, Audubon, Climate Central, Columbia Journalism Review, Discover, Nieman Reports, and many other publications. He has held a variety of editorial positions over the years, including a stint as editor-in-chief of Earth magazine. Yulsman has written one book: Origins: the Quest for Our Cosmic Roots, published by the Institute of Physics in 2003.


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