Snow blanketing Raleigh this weekend felt magical and rare, but more often it seems like the Triangle gets short-shrifted when it comes to the white stuff. Usually, the reports of flurries fill your social media feed from friends in Durham and Chapel Hill, but outside your downtown Raleigh apartment window there’s not a flake to be found. Perhaps you were curious enough to check the local weather radar, and in the middle, clear as day, you see a circle of cloudless skies over the area within the beltline.
The myth of the so-called Raleigh Weather Dome—the idea that an invisible force field or some geographic phenomenon protects the Oak City from snow—has persisted in some form or another for years.
National Weather Service (NWS) meteorologist Jonathan Blaes says there are no scientific reasons to explain why folks insist Raleigh is immune to inclement weather. While denser cities—think New York City and Los Angeles—can create heat islands, that’s not what’s happening in Raleigh.
There are, however, geographic factors that make the probability of snow inside the beltline spotty at best. To the west, there’s the Appalachian Mountains funneling cold air currents downwind. Then, there’s a current of warm water just offshore in the Atlantic Ocean, where water temperatures can reach 70 degrees even in the dead of winter.
“The natural tendency is for us to be in the mix zone for that reason,” Blaes says. “That often results in us being on the edge of the snow and people being bummed about that.”
But beyond the unpredictability of being in a transition zone, there are some very real statistical reasons why residents feel as though they are getting shortchanged on the good fluff.
In the last 60 years, the average snowfall has dropped 35 percent, according to data provided by the NWS. Climatologists use 30-year averages to accurately measure weather change over time. Data from Raleigh-Durham International Airport shows Triangle residents enjoyed an average of eight inches of snow between 1960 and 1990. The most recent 30-year analysis shows that average has dropped to just over five inches.
“In general over the last couple decades, we definitely are getting less snow and [fewer] snow days,” Blaes says. “That’s not to say we can’t get big storms anymore; they are just less frequent.”
If you’ve ever wondered why Raleigh occasionally looks like an oasis of clear air on a storm system radar, Blaes says there’s actually a reason for that, too. The nearest local radar is in Clayton, about 10 miles south of Raleigh. The beam points at a slightly upward angle, meaning the further from the radar, the higher in the sky it detects storms. That means in light storm systems high up, the radar may not detect activity in Raleigh while it shows storms elsewhere.
“With a lot of those urban legends, there may be a teeny, tiny little truth, but it tends to be overblown,” Blaes says. “The big problem is people’s emotions or perceptions misreading the data. And that seems to happen a lot.”
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Follow Senior Staff Writer Leigh Tauss on Twitter or send an email to ltauss@indyweek.com.
