Nature often supplies signs that severe weather is approaching.
One of these signs is MAMMATUS CLOUDS.
These unusual clouds are easily recognized by their bulbous, hanging appearance.
They are nearly always a sign that very turbulent conditions exist inside the clouds, which is a requirement for severe weather.
Mammatus clouds are usually dark, but can be highlighted with lighter colors, including green and yellow.
Any time you see hanging, round mammatus clouds, you can be sure severe weather is in the area.