We received a few photos from viewers around the area on December 21st, 2020. Today’s Ask Storm Team 11 question is, “What kind of clouds are these?”
These are called cloud streets, or convection rolls, and are parallel to the wind direction.
They form when convection is occurring in a more stable environment. In the summer when convection occurs in an unstable environment, clouds grow very large.
Where there are clouds, that is where warm air is rising. Where there are clear skies, colder air is sinking.
When do these clouds occur? When the conditions are just right.
-When winds are breezy at the surface, around 10-15 kts, and constant in terms of direction with height.
-When there is an inversion present. In other words, air temperature typically gets colder with height, but there is a layer where it actually warms. This creates a stable environment.
Looking at an atmospheric forecast sounding from that day, we had winds around 10 kts at the surface, consistent westerly winds with height, and an inversion present!
Thanks again to our viewers for sending these awesome photos in!