Thunder in winter: Will it snow within 7-14 days?
How true is the proverb: If it thunders in winter, it will snow soon after?
You heard thunder, and a few days later, snow showed up in the forecast. Many of us here in North Carolina have experienced this and taken it as proof the old adage must have some truth to it.
According to the Farmer's Almanac, this proverb rings true around 70% of the time, especially along the East Coast and in the Plains.
To simplify, this is because storms in winter are often caused by a big dip and sudden rise in the jet stream – and that rush of cold air, along with unsettled weather patterns, means by the time the next system arrives, it could still be cold enough to cause the next system's precipitation to fall as snow, instead of rain.
The North Carolina State Climate Office also backed up this logic, writing, "It makes some sense considering that weather systems generally take about a week to move across the country, so a strong cold front that produces thunderstorms is likely to be followed by another system within the next 10 days."
How often does it snow within 10 days after thunder in winter in NC?
The North Carolina State Climate Office shared research in 2013, when they looked up all reports of thunderstorms or lightning between December and March from six weather stations across the state.
Since the 1940s, they found 642 instances of storms, thunder or lightning in winter. Out of those instances, they found it then snowed within 7 to 10 days around 85 times. That means since the 1940s, there's been a 13% success rate of snow falling within 7 to 10 days of storms or thunder.
"This amounts to about a 1 in 7 chance, which is far from a sure thing," they wrote.
The North Carolina Climate Office also looked into data related to other winter folklore in North Carolina, such as whether or not woolly worms in Banner Elk can predict the winter's forecast.
So where did this folklore originate? It could be because there is some level of scientific explanation why it could snow soon after winter thunder, or because there's historically been at least a measurable chance that it will snow after a storm.
Or it could be because we believe thunder could mean snow is coming, so we pay attention – and when it works, we remember.
Remember some of North Carolina's most historic snowstorms?
While you wait and count the days, consider the blizzard of April 1915. Heavy snow that season shut down the Raleigh trolley system and shut down communication by telegraph.
Do you remember when Glenwood Avenue became nationally famous for the Snowmageddon meme of broken down vehicles and flames in the background?
And while you wish for snow this winter, take a look back at some of Raleigh's most memorable and historic snowstorms in North Carolina history.
