1-53. Upon receipt of a mission, commanders and staffs filter information categorized by the operational variables into relevant information with respect to the mission. They use the mission variables, in combination with the operational variables, to refine their understanding of their situation and to visualize, describe, and direct operations. The mission variables are mission, enemy, terrain and weather, troops and support available, time available, and civil considerations (known as METT-TC). Commanders and staffs view all the mission variables in terms of their impact on mission accomplishment. (See FM 6-0 for a detailed description of the operational and mission variables.)