When it comes to the weather, Old Farmer's Almanac sayings are great conversational pieces. Woolly worms and persimmon seeds are two of the popular ones in the Tri-State. Have you ever heard of the saying: Thunder in the winter means snow in 10 days? Unlike the worm and seed, this old-time saying actually holds some substantial meteorological truth.
Although hearing the roaring of thunder is a rarity in the cooler months, experiencing a thunderstorm December through February is not exactly out of the question in the Tri-State. In order for a thunderstorm to form the atmosphere has to create enough lift in the storm. Lift makes storm clouds grow vertically to enable the separation of negative and positive electrons, that is the recipe for lightning that is followed by thunder. In the winter, the easiest way for that phenomena to happen is to have a stagnant warmer air mass in place for days followed by a colder air mass to swiftly move in. The ushering of the colder air is usually separated by a cold front. Cold acrtic air is denser than warmer air, when it overtakes it the atmosphere becomes lifted which causes storminess.
Hearing thunder in the winter is not a slam dunk for snow in the next 10 days. The evidence that caters to the possibility of snow is the active weather pattern that is associated with stronger cold fronts for invasion of colder temperatures. Keep in mind, the following 10 days could bring cold air and also sunny skies. In fact, a study was done in multiple cities in North Carolina putting this premise to the test. The State Climate Office reviewed weather records dating back to the 1940s. They found that 642 days between the first of December and the end of February when lightning or thunder occurred. Snow fell 85 times within ten days of those 642 times. That is only 13% of the time.