Thundersnow
From Glossary of Meteorology
Thundersnow
Thundersnow is a compound of the words ‘thunder’ and ‘snow’ used informally to describe an observation of snow at the surface that occurs with lightning and thunder.
In the mid-latitudes, thundersnow is prevalent downwind of lakes (e.g., the U.S. Great Lakes) due to sensible and latent heating of the boundary layer, and also in mountainous regions when the environment is sufficiently unstable and/or when significant orographic lifting occurs in preferred areas. Additionally, embedded convective cells producing thundersnow can occur with intensifying extratropical cyclones. Thundersnow can be associated with increased snowfall rates leading to significant visibility reductions and localized areas of higher snow accumulation.