Where Does Thundersnow Come From?

Thundersnow — a thunderstorm that produces snow instead of rain — is being reported tonight across portions of the Mid-Atlantic and Northeast from the powerful winter storm that's lashing the region.

Convection — upward motion of air — helps produce thunderstorms. But it's fairly rare to have convection within a winter storm. (Thunder and lightning are much more common in warm-season thunderstorms, according to meteorologist Jeff Haby.)

When there's strong enough convection, along with plenty of moisture available, a winter storm can produce thundersnow.

Thundersnow is typically associated with very heavy rates of snow, which can lead to reduced visibility. And while the snow sometimes muffles the thunder, the lightning can still be seen, said meteorologist Grant Gilmore of WFMY-TV in Greensboro, N.C.

One of the more well-known instances of thundersnow occurred in 2011 in Chicago, which involved Weather Channel meteorologist Jim Cantore:

Thundersnow is sometimes seen downstream of the Great Salt Lake and the Great Lakes during lake-effect snowstorms too, according to the National Severe Storms Laboratory.