Virginia’s southern half should get brunt of snow
There are many reasons for winter weather uncertainty in Virginia.
This time, the main culprit is “the gradient.”
The northern half of the state may see little in the way of snow on Sunday and Sunday night, while the southern tier is preparing for quite a bit.
The Interstate 64 corridor from Covington to Richmond is shaping up to be a battleground between moisture from a low-pressure area tracking up the southeastern coastline and cold, dry air from high pressure over the Northeast.
That may result in a significant drop-off in snow totals between Chesterfield County and Caroline County, and possibly some big variations within individual counties.
These maps help us visualize the uncertainty by showing the chances of reaching certain thresholds. The top map shows the chance of getting at least 1 inch by early Monday morning.
On Friday, the National
Weather Service put Richmond’s chances of doing so between 50 percent and 60 percent.
Areas to the north and east have much lower odds for getting past 1 inch, while it’s very likely that Southwestern and Southside Virginia will get that much and more.
The lower map shows the probability of exceeding 6 inches of snowfall by early Monday morning.
The areas with a better than 50-50 chance of heavy snow are south of Roanoke and west of Interstate 85.
A 6-inch snowfall isn’t impossible for the Richmond area, but the odds were only about 10 percent as of Friday evening.
If any part of the state has a chance of seeing 1 foot, it would probably be in the Blue Ridge mountains or foothills south of Roanoke.
There will be plenty of moisture falling on the Tidewater region, but warmer temperatures near the coast will keep it mostly in the form of rain.
The leading edge of the snow will lift northward across the North Carolina line around daybreak on Sunday.
It may take until late morning or the afternoon for that snow to work its way toward Richmond.
Unless the snow stays to the south and misses us, the bulk of the metro area’s accumulation would occur during the afternoon and evening hours of Sunday.
Some pockets of above-freezing air in the clouds above could turn the wet snow into sleet and freezing rain at times, especially as the system tapers off on Sunday night.
Dry weather is expected to return on Monday.
A winter storm often brings subtle fluctuations in temperature and moisture, which can make or break a snowfall forecast. Those features are also hard to predict until they appear.
Don’t be surprised if Saturday brings a last-minute shift in amounts.