What conditions create the brown roller dust storms of Arabia?

The "brown roller" is a type of frontal storm that occurs in the Arabian Peninsula during the spring or fall. These storms are characterized by their sudden appearance on the horizon and can span up to 60 miles (100 km) in width.1

The conditions that create these storms involve the movement of a weather front that carries sand, dust, and debris high into the atmosphere. The arrival of a brown roller is typically followed by a sharp drop in temperature and, in many cases, rainfall. During these events, wind velocities can reach gale force for approximately half an hour.1