Late last night (or early this morning), a line of thunderstorms moved across the Piedmont. However, the question many people are asking is, “Why was the thunder so loud?!”
The line of storms moved through between 2 a.m. and 5 a.m. While the storms were not considered severe, they did produce extremely bright lightning and very loud thunder across most of the Piedmont.
According to the National Weather Service, last night’s thunderstorms were “elevated thunderstorms,” which means they started their lift from where the warm front was located above the ground. Because the air was warmer above the ground than it was at the surface, cold air was trapped below and refracted the sound of thunder.
In a normal thunderstorm, sound waves dissipate in all directions. However, because of the temperature inversion and warm air above the ground, the sound waves were trapped near the ground.
Here’s how the National Weather Service explains elevated thunderstorms:
“Sound waves move faster in warm air than they do in cool air. Typically, the air temperature decreases with height. When this occurs, thunder will normally have an audible range up to 10 miles (16 km). However, when the air temperature increases with height, called an inversion, sound waves are refracted (bent back toward the earth) as they move due to their faster motion in the warmer air. Normally, only the direct sound of thunder is heard. But refraction can add additional sound, effectively amplifying the thunder and making it sound louder.”
The National Weather Service said elevated thunderstorms are common in the winter as storms develop in warm air above a cooler air mass. Much of the sound waves from cloud-to-ground strikes remain below the temperature inversion giving thunder a much louder impact.