Friday AM snow: More south, less north, Roanoke on the bubble

[mahatmakanejeeves]

Friday AM snow: More south, less north, Roanoke on the bubble

Kevin Myatt 2 hrs ago

Weather patterns don't often easily align with county and state lines, but highways are sometimes a better reference marker. U.S. 460, the highway that connects Roanoke with Blacksburg, Christiansburg and Bluefield to the west and Bedford and Lynchburg to the east, is a fair divider for snow expectations early Friday.

Locations south of that highway have the best chance of seeing measurable snow on Friday, while locations along the highway -- about 15 miles either side, we'll say -- are a coin-flip to see white ground by midday Friday. North of the U.S. 460 corridor, there is less chance of snow accumulation, but it's not out of the question entirely, as these systems sometimes bump northward from expectations at the last minute.

A quick-moving low-pressure system, at the surface and aloft, will ride just south of our region early Friday, sweeping a limited but sufficient amount of moisture northward into just-cold-enough air over North Carolina and the southern part of Virginia to produce snowfall, starting near or just before sunrise Friday. The moisture will run into enough dry air to shut off at some vaguely defined point that appears likely to set up near the U.S. 460 corridor, but could vary somewhat north or south.

Surface temperatures will also be marginal, mostly in the 30-33 range, so snow will have to fall with some gusto to accumulate a lot on anything besides grass and exposed objects. That is more likely to occur to the south, where locations from about Pulaski to Floyd and Rocky Mount southward appear poised to see 1-3 inches, with locally heavier amounts especially near the North Carolina border and particularly the higher terrain of Grayson, Carroll and Patrick counties, which are under a winter storm warning for some possible 4+ amounts.

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Contact Kevin Myatt at [e-mail]. Follow him on Twitter @kevinmyattwx.

[phylny]

1. Whelp, good thing I had my car washed yesterday!

[mahatmakanejeeves]

2. UPDATE: Snow continues into afternoon with larger totals than expected in many locations

UPDATE: Snow continues into afternoon with larger totals than expected in many locations

Kevin Myatt 1 hr ago

UPDATE 1PM, 1/8/2021: Snow coverage, intensity and amounts have swung toward the upper end of what looked possible today, with widespread accumulating snow over most if not all of the Roanoke and New River valleys and higher snow totals than expected, some already near or exceeding 4 inches, in areas to the south and southwest along the Blue Ridge. The northern fringe has crept a little farther north than expected, though it is hitting dry air and probably won't make it all the way to the Interstate 64 corridor. Snow will continue for a few more hours this afternoon before gradually diminishing from the west, with many locations getting another inch or 2, locally 3. Travel conditions can vary dramatically by elevation and over just a few miles so beware that snow-covered roads may await you not far away even if it's not that way right in front of your house. END UPDATE

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UPDATE 10:10 AM, 1/8/2021: A band of light to moderate snow -- with a few heavy patches -- has spread up the Blue Ridge, across much of the New River Valley and into the Roanoke Valley at mid-morning. Some locations along and west of the Blue Ridge to the south and southwest of Roanoke have picked up an inch or 2 already. Temperatures are starting in the mid to upper 30s in Roanoke so accumulation will be slow to get started, but grassy areas and exposed objects may turn white as temperatures drop with any heavier snow that falls. The snow band is hitting dry air, so it may be some time after darker echoes move over your location before you see snow reach the surface, and the dry air will likely resist its spread too much farther north. END UPDATE

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Kevin Myatt
Since 2003, Kevin Myatt has penned the weekly Weather Journal column, and since 2006, the Weather Journal blog, which becomes particularly busy with snow. Kevin has edited a book on hurricanes and has helped lead Virginia Tech students on storm chases.

https://www.twitter.com/KevinMyattwx