Here “they” go again.
I’m sure that is being uttered in some quarters as a new snow chance pops up for the weekend in the Eastern U.S., possibly including Southwest and Southside Virginia, especially anyone who thought 20 inches was a legitimate possibility by late last week.
Yes, there is potential for snow late Friday into Saturday. And again, there are variable outcomes based on atmospheric subtleties, imperfectly reflected in shifting model data.
The early lean has been that it would be light to moderate snow in our backyards, with a larger storm coming together a bit too late and farther east, something that would be a bigger deal for eastern North Carolina and perhaps Hampton Roads. But some data over the past 24 hours points to — maybe — something larger and farther west.
For the Cardinal News coverage area, this isn’t something that can be solved on this Wednesday night weekly posting of the Cardinal Weather column, which is largely written the previous night. We will likely need to come back with a new Thursday night or Friday morning article describing what this storm is likely to do by then. If you don’t see one, you’ll know the storm looks minimal or a miss.
Arctic outbreak
Whether we add to it or not this weekend, whatever white icy shell you already have outside your window won’t be disappearing anytime soon.
We are in the throes of a deep Arctic outbreak.
The Arctic Oscillation is in one of its strongest negative phases in years, in which strong high pressure over the poles pushes the jet stream southward and deep cold air with it.
Meanwhile, the Pacific-North Atlantic pattern is in a moderately strong positive phase, featuring high pressure over western North America to pile-drive that southward oozing cold air into the Eastern U.S. The North Atlantic Oscillation is in a weakly negative phase, with high pressure near Greenland blocking the jet stream’s flow like a boulder in the stream and buckling it southward over the Eastern U.S.
This is the trifecta that defines most of our coldest winter periods and spawns many of our larger winter storms, historically, though sometimes it just passes very cold but dry.
Occasional Arctic cold fronts are reinforcing the chill. A few spots in our region may have managed to poke barely above freezing on Tuesday and Wednesday, but the rest of the week, continuous single-digit and teens lows and subfreezing highs are likely through the weekend into next week as well.
Also, from time to time, upper-level shortwaves, pockets of strong winds aloft, pass through with the potential to spin up a storm, especially if the northern and southern branches of the jet stream combine forces.
And that leads right into the possible weekend snow, which this time, will be “snow or no” rather than any kind of mix like our last remarkable storm.
Sleet’s finest hour
For most of Southwest and Southside Virginia, sleet robbed us of a huge snowfall and a huge ice storm, while creating a huge mess of difficult-to-remove white concrete 2 to 8 inches deep on many roadways.
One meteorologist described this past weekend’s storm as the Pineapple Express meeting the Siberian Express — a dense ribbon of subtropical moisture running into and over an advancing Arctic air mass.
This past weekend’s winter storm brought on one of the most extreme examples ever of warm air advection running over the top of a dome of surface Arctic air trapped by cold-air damming, or high pressure pressing a pool of cold air against the Appalachians.
A Sunday weather balloon launch from Greensboro, N.C., revealed a temperature of 55 degrees about a mile above the surface, while it was still 16 at ground level. Temperatures went well above freezing on the summits of Mount Rogers and Apple Orchard Mountain in our region while lower areas stayed well below freezing.
Snow falling high aloft melted in the warm layer, but then refroze into ice pellets on its way down, collecting in unusual quantities. Sleet is more often a brief transitional precipitation between rain and snow, snow and freezing rain, etc. It is not often the star of the show with wintry precipitation.
Sleet collects in a white mass like snow, but is more densely packed, so the same amount of moisture that would collect 10 inches of snow makes only about 3 inches of sleet. But sleet also does not collect on tree limbs and power lines like freezing rain … it bounces off.
Ice was bad in pocket of Southwest Virginia
Fortunately, the cold air stayed deep enough long enough for a lot of sleet and not much freezing rain — for most of us.
There was a zone in Southwest Virginia, focused on Washington County and parts of neighboring counties, that slipped between a warm push to the west that turned precipitation to rain, and the cold air dome that kept it falling as sleet to the east.
And that area experienced a major ice storm with tree damage, disrupted power and tractor-trailer rigs sliding off highways.
Abingdon is the capital city of winter misery in our region, presently.
The two early December snows that were mostly just pretty with only brief problems largely scraped to the north, leaving Abingdon with a lone inch total, not pleasing to snow lovers there.
And this most recent storm maximized its glaze ice in and near Abingdon, even as most of our region took its slightly distasteful sleet medicine to ward away an ice storm.
Washington, Smyth and Grayson counties were the northeastern-most extension of an ice storm that has been downright catastrophic near Nashville, Tennessee, and Oxford, Mississippi, and stretching back as far southwest as parts of Texas.
It wasn’t ever going to be 20 inches of snow
I’m not going to name names, but there are a few large companies who need to get their smartphone apps in gear. Those things are always pumping up ridiculous snowfall totals even sometimes right in the middle of a storm that is obviously not going to be that much, and it’s doing damage to the entire meteorological enterprise.
Local meteorologists end up getting the guff when “they said we’d get 20 inches” but there is no “they” and there was never any widespread expectation of 20 inches or anything close to it among legitimate meteorologists who actually know our region’s weather history and trends.
By the end, most of the TV meteorologists had similar forecasts. Some of their ranges were slightly different, but it’s funny how 3-6 and 5-9 actually overlap on a couple of numbers that ended up being exactly correct for some of the locations within those range bands.
The National Weather Service map we posted here in a Friday storm preview was a little high but came down by Saturday as it became apparent that the early phase of the storm would be a bit drier and more of the accumulation later would be sleet, not snow.
What your smartphone app is doing when it shoots out a big snowfall forecast is keying in on a single model that may be showing something like that as it moves toward a more reasonable solution. It is a passing thought, not a way of thinking to build plans around.
As I said a couple weeks ago here, the big one we finally do get here will probably not be something hyped up a week ahead of time, but rather something that seems very iffy at first, then a chance of light snow, then build to a more obvious moderate-heavy snow, and finally the big numbers come out from lots of sources n the last 24-36 hours.
Our region’s big snowstorms in December 2009 and February 2014 followed that basic progression. December 2018 looked big at first, almost disappeared, then reappeared and got progressively more intense-looking in the last 48 hours.
Could this coming weekend be that kind of thing? Maybe, but leaning no for the moment. Let’s see where we are on Thursday night.
Snowfall contest totals to date
For those with entries in the snowfall prediction contest, here is where we are right now with total snowfall since Dec. 1, rounded to the nearest inch. Yes, sleet counts as snowfall officially.
Roanoke and Lynchburg are knocking on the door, literally within tenths of an inch not displayed in this listing, of their snowiest winters of the 2020s, not that that’s a high bar.
And Abingdon, as noted above, is the surprise cellar dweller, even slightly behind the Southside sites — for now.
Whether we get snow this weekend or not, we’re probably not done adding to these totals, before mid-February let alone the contest period close date on March 31.
Abingdon: 3
Appomattox: 13
Blacksburg: 14
Burke’s Garden: 21
Clintwood: 10
Danville: 5
Lynchburg: 11
Martinsville: 5
Roanoke: 12
Wytheville: 9
Journalist Kevin Myatt has been writing about weather for 20 years. His weekly column, appearing on Wednesdays, is sponsored by Oakey’s, a family-run, locally-owned funeral home with locations throughout the Roanoke Valley.
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