What Is An Inversion?

You may hear us occasionally throw the term “inversion” around here on WeatherNation, but what does it mean exactly? Well, let’s take an example from Wednesday morning the 9th of December.

Wednesday morning’s weather balloon launch in central Oklahoma showed a distinct inversion. Take a look at the red line, pictured above. That red line represents the air temperature from the ground level (bottom of the graph) to the top of the troposphere (near the horizontal 200 line). You’re looking at a Skew-T diagram, commonly used in weather observation and prediction by meteorologists. We want to point out the very bottom part of that red line. Look where it says 35, that means it was 35 degrees at ground level when the weather balloon was launched. The red line then jumps to the right, meaning the temperature rapidly rose as the weather balloon floated upward through the sky. Here is the raw data of the lowest level of the atmosphere:

• Ground level, Norman: 35 degrees
• 130 feet above ground: 48 degrees
• 440 feet above ground: 63 degrees

This is an example of a strong inversion! Normally, temperature *decreases* with height. That’s the reason why it’s normally colder at the mountain peak you’ve hiked to, compared to the valley where you started. On Wednesday, it was the opposite. The temperature *rose* 28 degrees from the surface to 440 feet above ground level in Oklahoma.

Let’s take a look at another example of a strong inversion Wednesday, this time in Dodge City, Kansas.

The temperature inversion was not as strong as Norman’s Wednesday, but it was still rather impressive. The temperature *rose* 32 degrees from ground level to 1,040 feet above the surface.

Why are temperature inversions important?

An inversion is important when it comes to poor air quality, smoke, fog, and haze. When the temperature is hotter above the ground, it puts a “lid” on the atmosphere where the cool air near the surface cannot escape. That means the air sits still and that can lead to very poor air quality.

Inversions play a critical role in winter precipitation type and predicting what kind of precipitation will fall at your location. Warmer air, above freezing, above the surface throws a wrench in precipitation because it oftentimes results in freezing rain or sleet (depending on how much warm air is there).

When coastal areas, such as California, get a marine layer it results in an inversion. The cool, dense air stays near the surface while the mountains stay warmer and drier. This can be important in forecasting how long a marine layer my linger.

Finally, an interesting result of inversions:

An inversion can also lead to louder noises, because the sound travels and then bounces off that warmer layer above the surface, bounces back and results in some noisier surroundings!

Please share this article if you’ve found it useful!