Large Scale Weather Patterns
There are many weather patterns that can be responsible for the development of lake effect snow. In North America, winter storms often happen when a cold and dry air mass or cold front, moves down from Canada and collides with a warmer and humid air mass or Warm Front, from the Gulf of Mexico.
This situation provides favorable conditions for lifting the warm, moisture-filled air up for cooling and ice crystal formation and winds will blow out of the northwest across the Great Lakes. Depending on the location and movement of a high or low-pressure system, the winds can shift directions and produce fetches across the Great Lakes, which can cause lake effect snow events.
Source: ERH | NOAA