GREENSBORO, N.C. -- Many have heard the Old Wives Tail that if you hear thunder in the winter then it will snow in 10 days. While there are slight variations to this saying, believe it or not, there is some science that actually supports this theory.
While there are exceptions, most of the time when it thunders in the Triad in winter the jet stream has a big dip (trough) and a big rise (ridge). The jet stream is the barrier between the cold air to the north and the warm air to the south.
When there is a big ridge in the jet stream warm air surges north while cold air conversely surges south in the resulting trough. There are a number of reasons for this undulation in the jet stream, but the end result is active weather. The most active weather can be expected to occur along the boundary between the greatest contrast between the warm and cold temperatures. This is where you will likely have storms that will create thunder (Day 1).
The cold air will continue to advance east and take over the area that was once in the ridge (warm air). This air mass take-over usually takes a few days (Day 2-5). During this time another storm system will likely begin to develop out west and become picked up by the jet stream. Over the next few days the storm system will move east and eventually approach the area that experienced the thunder which continues to experience that relatively cold temperatures. If the conditions are correct then the approaching storm system will have enough moisture to mix with the cold air to produce snow (Day 5-10).
Thunder in winter does not always indicate that it is going to snow in the near future, but it does indicate an active pattern. And an active pattern in winter will definitely generate a better chance of snow then a non-active pattern.
The WFMY News 2 Meteorologists figure that when it thunders in winter in the Triad there is somewhere between a 50-70 percent chance of receiving snow within the next 7 days.
WFMY News 2