Surfing the Waves in the Sky
December 20th, 2011 at 9:00 am by Ashley Baylor under Weather
- Courtesy: ABC 33/40 in Birmingham, AL
Hang 10 in Birmingham, Alabama! People in the heart of Dixie woke up to these huge breaking waves in the sky last Friday (Dec. 16th)! Just amazing – a once in a lifetime sight!
Get ready for this 10-dollar word – these are Kelvin-Helmholtz waves! We can relate these waves in the sky to the waves in the ocean. Water waves form when the air above them is moving faster than the water below. When the difference between the wind and the water speed increases to a certain point, the waves “break” – meaning their crests lurch forward.
When you have air in the upper atmosphere moving at high speeds over a cooler, denser layer of air, the convergence of the two layers can cause these waves to form. These Kelvin-Helmholtz waves indicate instability and turbulence in the atmosphere.
In Birmingham, they had a cold, dense (stable) layer of air near the ground with light winds..sitting above those clouds was a warmer, faster-moving (unstable) layer of air. In the picture, you can see the faster-moving air in the upper atmosphere is causing the tops of these waves to lurch forward..almost like ocean waves getting ready to crash on the shore.
Anytime you take any cool weather pictures, be sure to send them to us at REPORTIT@WWLP.COM
-Meteorologist Ashley Baylor
