When meteorologists are discussing severe storm radar images, they sometimes mention a feature called a “bow echo.” This is a radar feature that shows a line of storms bent into the shape of a bow. Strong straight-line winds are often found at the crest, or center, of that bowed image. Areas of circulation sometimes form at either end of the bow. This can lead to tornado development, particularly on the left, usually the northern, edge of the bow. So, if you in the path of a bow echo, it’s another indication to take the storm seriously.
Mary Knapp, Weather Data Library