Winter Weather — Eastern Loudoun, Virginia

2021-02-18 to 2021-02-19 · Eastern Loudoun, Virginia

Event narrative

VA-621 Bull Run Post Office Road was closed due to ice from freezing rain and an accident between Hollyspring Lane and Sudley Road around 9 PM on the evening of the 18th.

There were also multiple accidents from icy roads on VA-643 between VA-659 and VA-653.

Wider weather episode

Low pressure passed by to the west as it tracked into the Ohio Valley and Great Lakes on the 18th into the morning of the 19th, before transferring its energy to a coastal low along the Mid-Atlantic Coast. The coastal low moved out to sea later on the 19th.

Canadian high pressure supplied plenty of low-level cold air, but warmer air worked its way in aloft, and this caused a wintry mix of snow, sleet, and freezing rain. Snow and sleet overspread the area on the early morning of the 18th. Snow and sleet changed to a light wintry mix including freezing rain by the evening of the 18th. Precipitation ended as a period of light snow and sleet on the morning of the 19th.

The highest snowfall accumulations (around 4 to 8 inches) were across the northern Shenandoah Valley toward the northern Blue Ridge Mountains of Virginia where the heaviest precipitation occurred, and temperatures aloft were cold enough for precipitation to start off as snow. However, mostly sleet occurred across central Virginia toward the Washington Metropolitan area, so accumulations were less (around an inch or two).

Ice accumulation from freezing rain was up to a tenth of an inch for most areas, but around a tenth to a quarter inch in the Virginia Piedmont where warmer air aloft cause more freezing rain vs. snow or sleet.

Source: NOAA Storm Events Database, event_id 937539. Narrative written by the NWS forecast office that issued the report.