© 2024 Louisville Public Media

Public Files:
89.3 WFPL · 90.5 WUOL-FM · 91.9 WFPK

For assistance accessing our public files, please contact info@lpm.org or call 502-814-6500
89.3 WFPL News | 90.5 WUOL Classical 91.9 WFPK Music | KyCIR Investigations
Play Live Radio
Next Up:
0:00 0:00
Available On Air Stations
Stream: News Music Classical

Inversions can turn temperatures upside down and create fog

Jenna Anderson

Every week WAVE 3 meteorologist Tawana Andrew breaks down what we know and what we don't about the climate and weather here in Louisville.

Bill Burton: It's Friday and it's just not a good Friday without Science Behind the Forecast with WAVE 3 meteorologist Tawana Andrew. Good morning, Tawana.

Tawana Andrew: Good morning, we're talking about something that kind of makes the atmosphere a little topsy turvy.

BB: Well said, we're talking inversions today in all of its forms. What do we need to know about inversions?

TA: Yeah, they're not really a well known weather phenomena, but they can play a big role in the type of weather that an area sees. So as you rise from the ground and go higher in our atmosphere through the troposphere, which is the level of the atmosphere closest to the surface, the temperature as you go up, typically decreases. So you have colder air sitting above warm air. And with a temperature inversion, you actually have temperatures increasing as you climb through the atmosphere. So that warm layer is sitting over cold air think a warm blanket over a cold bed, kind of a situation. Okay? So inversions can dictate how clouds form, the types of precipitation you see in an area and even invisibility. So an inversion is basically a Tupperware lid on the bowl, that is our atmosphere.

BB: That's a great visual.

TA: Yeah, like everybody knows what, what to do with those, right? So what it does, it basically limits the upward movement of air from the lower parts of the atmosphere. And by doing that, it prevents air pollutants, smoke, dust from being dispersed across our atmosphere. And that causes an accumulation of particles, which can reduce visibility, and cause health issues for anybody with breathing ailments. That's why in the summer, you tend not to have a lot of movement in the atmosphere when we have inversions, like that. And people with asthma have a little bit more of those issues on those days. It also limits convection. So that limit of convection, it's not the air is not moving around, the heat is not moving around in the atmosphere, and that keeps clouds from growing too high. And that prevents precipitation from happening if the cloud isn't able to grow. And if the air is colder at the bottom five, an inversion like it usually is, you'll actually end up with fog forming in some areas, when there's an inversion. The inversion, I understand, most people know the one that causes fog. And that actually is a ground inversion. So a ground inversion forms when you have that air cooled by contact with a colder surface until the air temperature drops below that of the atmosphere above. So basically, you have a grounded version happening on clear nights, when ground temperatures drop quickly due to radiational cooling, that air comes on top of that. And when the temperature drops below or meets the dew point, then you end up with fog forming. So that's the first one. There's a second one a frontal inversion that happens when you have cold air moving through. And basically what it does is kind of slides under and shimmies under a warm air mass and lifts it. So that typically happens when you have a front moving through an area and it's the frontal inversion. There are turbulence inversions. And those form when you have calm air, sitting over turbulent air, and in that turbulent air, the consistent movement starts pushing the heat towards the ground, and eventually it cools the upper parts of that layer, and eventually the air below becomes colder than the calm warm air above, which is not necessarily the best of things to fly through.

This transcript was edited for clarity

Bill Burton is the Morning Edition host for LPM. Email Bill at bburton@lpm.org.

Can we count on your support?

Louisville Public Media depends on donations from members – generous people like you – for the majority of our funding. You can help make the next story possible with a donation of $10 or $20. We'll put your gift to work providing news and music for our diverse community.