Thursday night will be cold and dry, with lows in the mid-20’s across much of the Shenandoah Valley. On Friday, high pressure will move off the Northeast coast, with light precipitation moving northward from the Carolina’s into Southwest and Southern Virginia. Classic cold-air damming event (cold air trapped at the surface) will result in a period of freezing rain.
Freezing rain will move into the New River Valley and southern Blue Ridge around 2:00 a.m. Friday. The freezing rain will begin as a period of spotty, light freezing drizzle, with light and steadier freezing rain just before sunrise.
Temperatures early Friday morning will be in the mid 20’s across the Shenandoah Valley. One concern is that evaporational cooling may prolong the event, with low dew points settling in right before the arrival of precipitation. This may allow temperatures to fall a few degrees lower, preventing temperatures from rising rapidly — resulting in a prolonged period of freezing rain.
Around 7:00 a.m. Friday, freezing rain will work into the Central and Northern Shenandoah Valley and Piedmont. Temperatures are still in the twenties, with near freezing temperatures east of the Blue Ridge, as milder air works in from the Atlantic. A east-northeast flow will likely create additional precipitation, with concerns for ice accumulation on secondary roads, bridges, and overpasses.
Around Noon Friday, freezing rain will changeover to a cold rain, as temperatures rise just above freezing. The afternoon will remain very cold in the Shenandoah Valley, with temperatures struggling to climb out of the mid-30’s. Another wave of moisture (rain) will move into the area Friday afternoon and Friday night, with rising temperatures during the overnight hours.
If you are traveling from I-64 to I-81 down to I-77 in the Central Piedmont and Valley, southward into the New River Valley, untreated roads will be slick and slippery — especially secondary and less traveled roads. Also, bridges and overpasses, sidewalks, and other cold surfaces, will likely have ice accumulation. Main highways and interstates should be “OK” for the most part as they will likely be pre-treated before the storm’s arrival. However, a few slick spots are possible.
We predict that many schools in the Roanoke and New River Valley area will delay, with a 50 percent chance of closing all day. Some locations in the New River and Roanoke Valley area may still hold on to freezing rain until 2:00 p.m.
Even after temperatures rise a few degrees above freezing, it will take a few hours for ice to melt from bridges, overpasses, and elevated surfaces.