Air Mass Sources
Several factors go into wintertime temperatures, though there are six common air masses that determine what the overall pattern holds.
Siberian air masses are the coldest and come from the north out of Siberia. These often produce record cold temperatures across the lower 48. Pacific and Gulf air masses pull in warmer air, though are also often associated with precipitation. Polar and Maritime air masses come from the north and northeast and are cold, but not overly extreme.
By Justin Povick Meteorologist
