As forecasted we got those thunder showers around 2-4am this morning. What was shocking and startling to so many was just how loud the thunder was. The storms were not very strong at all and as thunderstorms go they really didn’t produce a larger than average amount of lightning. So what was going on?
These storms were what we call “Elevated” thunderstorms. Which means they started their lift from where the warm front was above the ground and not from the ground itself like an average thunderstorm. These average thunderstorms we call “surface” based storms form when it’s warm and humid at the ground. The average storm starts it’s lift at the surface for this reason.
Why Inversions Matter:
Last night we had an temperature inversion. When looking at the temperature profiles of the atmosphere last night we look at what we call soundings. These are produced by weather balloons but also satellites and model data can produce similar soundings. The sounding from Greensboro this morning and the forecasted sounding from 3 am this morning both showed a temperature inversion. Which means it was actually warmer around 1,000-5,000’ than at the ground. This inversion was likely the warm front moving in. These inversions can trap cold air below them, sometimes pollution and in this case it helped trap sound.
So what happened last night?:
The elevated thunderstorms produced lightning which created the sound of thunder. Normally with a thunderstorm these thunder sound waves would dissipate and propagate in all directions. Last night due to the inversion the sound waves got trapped near the ground. This was the equivalent of setting off fireworks in a closed room verses outside in the open.
These inversions can also allow for the sound waves to travel very far distances as well. This is called atmospheric ducting and works on radio waves and other waves. These inversions can make you pick up radio stations and TV stations over the air at very long distances. They are also the main reason we get ground clutter on our First Warn Doppler Radar at night when the sky is clear.