2:15 p.m. update: Indeed, the snow hole is still largely in effect at this point. There are some very, very light snow showers (or flurries) out in the colder western suburbs. To the north and south of Washington, snow continues to fall and even stick to roads in some areas. But alas, no snow for us.
Link: Detailed forecast
This has been the winter of the D.C. snow hole. On multiple occasions, it has snowed everywhere around the D.C. region, but not in the D.C. region itself.
Today (Monday) is a classic case. It’s snowing in Harrisburg, Pa., and Charlottesville, but nary a flake has come down in Washington.
Some like to joke that politicians blowing hot air cause the D.C. snow hole, but in reality, there is some straightforward science to explain the phenomenon.
Two streams of flow in the atmosphere are pointed at the East Coast: one through the Ohio Valley toward the Northeast, and a second through southern South Carolina toward the coastline.
The weather disturbances riding along this flow are situated just slightly too far north and too far south, respectively, to produce precipitation in the Washington area.
We would see more precipitation if these two disturbances were closer together, tracking toward the Mid-Atlantic.
If the southern disturbance were tracking through northern North Carolina rather than through southern South Carolina, Washington would probably experience substantial snowfall. Not only would the disturbance be closer to Washington, but its proximity to the disturbance in the Ohio Valley would allow the two streams of flow to merge and potentially produce a big storm, right off the North Carolina coastline. (Some computer models in recent days wrongly predicted this.)
Instead, because the two streams and two disturbances are separated by so much distance, they won’t come together until they’re well offshore the Delmarva Peninsula — in time to produce another big nor’easter for eastern New England, but way too late to have much, if any, effect on Washington.
Circumstances such as these this on several previous occasions have resulted in our very low snow total, just 3.7 inches for the winter.
The multiple snow holes are a result of luck or chance; there’s no magical shield protecting the Washington region from snow.
In some winters, storms repeatedly track toward the region and we get hammered. This is just one of those years in which the atmosphere’s steering flow has done its best to stay away.
The lack of storminess, to a certain degree, is a reflection of the La Niña pattern, which tends to separate the flow of weather disturbances from converging on our region. Before winter, we predicted slightly below-normal snowfall for this reason.
That said, even in past La Niña winters, at least one significant storm has struck the region. To see every promising potential winter storm fall apart as it has this winter has gone beyond anything we imagined.
More snow holes…
From January 2013: The Washington, D.C. snow hole: Version 3.0
From December 2010: No-mageddon: The Washington, D.C. snow hole