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We are at that stage where every wrinkle, wiggle and swirl moving through the atmosphere must be monitored for its potential to produce a winter storm that might affect Virginia.
The large-scale cold pattern discussed in last week’s Cardinal Weather column has continued to develop over North America to the point that colder than normal air is set to spread across three-quarters of the contiguous 48 states, particularly focused on the central and eastern U.S., over the Christmas holiday season.
Enough of that cold air is already sliding into Virginia that the northwest part of the state – mainly west of Interstate 81 and north of Interstate 64 – may experience significant icing and possibly some wintry mix overnight on this Wednesday into early Thursday.
Farther south in Cardinal News’ core region, higher elevations along and west of the Blue Ridge, may see patchy ice overnight on this Wednesday into early Thursday while a cold rain pours on most of us in Southwest and Southside Virginia.
After a cold front pushes through behind this system, we are going to be in persistently cold air for many days to come, teens to 20s lows and 30s to 40s highs. This is the kind of temperature scheme in which we’ll have to watch as disturbances move across the southern U.S. at the edge of the colder air.
There is one such system moving through early next week, around Tuesday – it appears as of this writing to stay suppressed to the south and not strengthen much. But every now and then, there is a forecast model run that amplifies it and spreads a shield of snow and wintry mix across the Tennessee Valley and into the Appalachians and Mid-Atlantic.
So it’s worth keeping an eye on it to see if this re-emerges as a wintry precipitation threat even though most forecasts are now calling for cold and dry for early next week.
Recall the suddenness of last winter’s first snow in our region on Jan. 3, when we went from a Saturday forecast of maybe brief light snow on the coming Monday to winter storm warnings by Sunday and stranded motorists on Interstate 95 by Monday night.
In the days before Christmas, there appears to be a good chance of a larger storm system forming somewhere over the central and eastern U.S. It’s simply too early to discern any details about this, including whether or not it will snow or ice or rain on us, but be aware it’s out there, as your holiday travel plans in or out of our region could be affected.
While there is some potential for one or more systems to deliver wintry precipitation to our region between now and Christmas, the days between Christmas and New Year’s Day, even into the first days of 2023, may line up even better for snow potential in Virginia.
The missing piece of the wintry pattern earlier this month – high pressure in the West – is expected to build in by then, flipping the Pacific-North America pattern from the negative phase to positive. That high’s clockwise rotation will help drive Arctic air deeply southward over the Eastern U.S.
Combined with a strongly negative phase of the Arctic Oscillation – high pressure over the North Pole pressing frigid air away from the pole – and a weaker negative phase of the North Atlantic Oscillation – high pressure over Greenland blocking the jet stream and forcing it south – the pieces will be in place that historically favor winter storms tracking across the South that could bring snow and/or ice to our region.
This is never a certainty – it is entirely possible to sail through such a period cold and dry. But it is probable that part or all of our region sees some significant snowfall if such a cold pattern lasts at least a couple of weeks, as appears likely at this point.
If something snowy does come to fruition, it won’t necessarily be a “big one.” But most of our region’s large snowfall events and many small to medium ones do occur with the alignment of NAO-negative, AO-negative and PNA-positive phases.
Think of it as the high over the North Pole making the Arctic air available, the high over the West driving it southward, and the high over Greenland keeping the cold from escaping too quickly. The jet stream is also displaced southward by all three of those factors, providing a path for storm systems.
A cold Christmas contrasting dramatically with record warmth a year ago appears to be a near-certainty.
Snow futures will continue to be somewhat uncertain until and unless there is a single storm system we can focus on about three days out – and even then, there is almost always some uncertainty right up until the flakes start falling.
Monitor your trusted local media sources, the National Weather Service (weather.gov/Blacksburg) and my weather-focused social media (@KevinMyattWx on Twitter, Kevin Myatt’s Weather Wonders on Facebook) to keep track of if/when this may develop.
If a winter storm gets to be a near-certainty for a sizeable part of Southwest and Southside Virginia, we’ll update here on Cardinal News as well, even if it’s not a regular Cardinal Weather day.
WEATHER STATS OF THE WEEK
With at least some reasonable potential for snow on our holiday horizon, it’s a good time to review recent December snow in our region.
December snowfall in Southwest and Southside Virginia can best be described in recent years as feast or famine – historic snowstorms with many foot-plus amounts on Dec. 18-19, 2009, and Dec. 9, 2018, and really not much most of the other winters of the 2010s and early 2020s to date.
Lynchburg has had no measurable December snow – either zero or a trace – in eight of the past 10 years, including six in a row from 2011 to 2016. Same thing for Danville.
The only comparable December snow dearth for Lynchburg on record occurred in the 1920s, when the Hill City went six of eight years from 1920 to 1927 getting no measurable snow in December and less than an inch in the other two.
Since the Dec. 18-19, 2009, snowstorm dumped almost 18 inches on Roanoke, the Star City has topped 2 inches in only two of 11 Decembers. From 2011 to 2016, Roanoke had only 0.3 inch of snow total in December, with five of those six Decembers measuring zero or a trace, four consecutively – the first time that had happened since 1918-21.
Blacksburg measured less than an inch of snow in seven of the 11 Decembers from 2011 to 2021, including five of six 2011 to 2016 with just 1.9 in the other one, 2012.
Southwest Virginia west of Interstate 77 saw similar effects. Burke’s Garden in Tazewell County, which averages about 9 inches of snow each December, had no more than 3 inches each December from 2013 to 2016, including no snow at all in December 2015. Last December also produced no snowfall at Burke’s Garden. Bluefield, W.Va., just across the state line, got less than one inch in December from 2013 to 2015, and also no snowfall at all last December. Tri-Cities Airport just across the state line from Bristol, Virginia, saw no snowfall in December 2011 to 2016 except for 0.6 inch in 2012, with no December snow again in 2021.
There isn’t much correlation between lack of snow in December and lack of snow for the winter as a whole. In fact, the first three of Roanoke’s four consecutive recent snowless Decembers were part of winters that marked the first time Roanoke got more than 20 inches of annual snow in three consecutive years since the late 1970s (which also, curiously, had some not-snowy Decembers). The all-time record snowy 1959-60 winter, with almost 63 inches at Roanoke, also had a snowless December.
Big snow in December 2009 was followed more big snow in January and February for our region, but the big snow in December 2018 was followed by only small snows in January and February.
There just is no template for what snow in December means for the rest of winter.
We’ll soon see if this December follows suit with several recent nearly snowless ones, if it has the infrequent big snow lurking like 2009 or 2018, or something in between that has been lacking of late.
Journalist Kevin Myatt has been writing about weather for 19 years. His weekly column is sponsored by Oakey’s, a family-run, locally-owned funeral home with locations throughout the Roanoke Valley.