Asperatus clouds observed in Cincinnati, Ohio by Ron Steele on August 3, 2015.
Spectacular images of undulatus asperatus clouds were captured on Monday in Kentucky and southern Ohio and shared on social media.
Undulatus means wavy and asperatus translates as agitated or roughed, so the name is Latin for “agitated waves.”
Asperatus clouds captured by Johannah McKinney Cheek in Harrodsburg, Kentucky on August 3, 2015.
Undulatus asperatus clouds are a rare formation that was proposed as a new category of cloud in 2009, according to the National Weather Service, and is likely to become the first cloud formation added since 1951 to the International Cloud Atlas of the World Meteorological Organization.
In this case, these incredible images were seen while thunderstorms were in the area early Monday morning.
Asperatus clouds captured in Lawrenceburg, Kentucky on August 3, 2015 via Facebook by Kathy Bickers.
These ominous looking clouds can sometimes be observed ahead of a thunderstorm, after the thunderstorm’s gust front has blown through. In other words, ahead of either a single thunderstorm or line of storms, you may first experience a strong gust of wind, which is the gust front. Look skyward (from a safe place in a thunderstorm, that is) and you may see these undulatus asperatus clouds.
What these clouds really depict is turbulent wave motion. According to Graeme Anderson, from the Department of Meteorology at Reading University, winds at cloud level lead to sufficient wind shear to produce the wavy motion. The wavy motion of the air becomes visible in the form of undulations (waves) in the cloud base.