What is causing this heat?

Credit: Marc.333 on click2pins--the hottest he has ever seen it!

I’ve had more than a few viewers ask just where this heat dome we keep talking about comes from and how do we make it go away? The whole concept is pretty easy to understand so let’s get going. First, it’s summer and our highs average 93-96° and so a few temperatures of 100° are to be expected. The problem of course is that day after day we’re hitting 100° or higher and even our overnight lows struggle to fall below 80°. So the summer season we are in is part one.


Check out the map below and you’ll see we are surrounded by warmer than normal water these days. While the Atlantic warm water is a player for the tropics, the Pacific warm water heats the air above it and trade winds drive it in to North America. That is the heat source for our Heat Dome and you can read more here from that National Oceanic and Atmospheric Association (NOAA):

Credit: tropicaltidbits.com

The warmer than normal air gets trapped by High Pressure. Why is it called High Pressure? Because air has weight (approximately 15lbs per square inch) and we measure the weight of the air with a barometer: the higher the reading the heavier the air. H=High=Heavy! Heavy air sinks toward the Earth’s surface and that downward compression heats up. In addition, with all the heavy, sinking air you don’t have much rising air so few clouds form to help out, much less rain. Basically, an elephant of air is sitting on top of us.


So how to end this? The Jet Stream, those stronger than normal upper level winds around the globe are the answer: those winds bring down colder air from the arctic and that cold air eventually will break the dome and we get back to normal. But that is the whole problem. First, let’s look at today’s Jet Stream and you’ll see there isn’t much to it. The yellow and green colors are the weaker winds so the southern jet is very weak and the northern one (I made the white arrows) is weak and way north.

Credit: tropicaltidbits.com

Neither of these Jet Streams is helping to quash the Heat Dome. And it’s happening all over the world. Check out this example from the United Kingdom Meteorological Office:

Credit: United Kingdom Meteorological Offfice

So why the weak Jet Streams?


Recent articles all point to the same culprit: the Arctic circle is FOUR times warmer than normal. You’ve heard about the Global warm up and how hot the world is--the Arctic is outpacing that warm up! Last year, 2022 was the 6th warmest on record for the Arctic and Greenland Ice Sheet has been thinning for 25 years. That is our COLD source and it ain’t cold. You can see a simple read from the National Oceanic and Atmospheric Administration right here.


So here is the down and dirty equation: Warmer Ocean Water = Warmer Air moving into the country. That warm air builds into a Heat Dome that can’t be broken because the Jet Streams are too weak. The Jet Streams are too weak because the Arctic it too warm. Global Warming, folks. But you knew that would be the answer.

The tough part is that this is here to stay. We are in a warmer world and unless we make substantial changes to get it cooler, then that Heat Dome has found its home.

On a positive note: it’s the weekend! Stay cool and enjoy it!


Email me with comments and questions.

About the Author:

KPRC 2's chief meteorologist with four decades of experience forecasting Houston's weather.