Ice Expected Sunday... Impacts Iffy
Lynchburg, VA - The ingredients are on the table for significant icing in Greater Lynchburg and Southside Virginia.
First off remember it will be unusually warm Thursday and Friday. After several hours of rain Friday night, the colder and drier air will follow for Saturday, setting the stage for some ice on Sunday.
As always, there are a few things that we feel good about, and some things that we do not. Preliminary thoughts
Timing of Precipitation
Beginning Sunday between daybreak and noon. Ending between late Sunday night and daybreak Monday.
Mostly freezing rain. Remember, freezing rain is liquid that reaches the ground and freezes on contact, giving the icy glaze that accretes on surfaces. Cautiously optimistic there will be a change to rain a couple of hours before ending, but not particularly confident.
Up to an hour of light snow is possible at the onset of the precipitation, but a quick transition to freezing rain is expected. Accumulating snow is very unlikely.
Amount of Precipitation
Low confidence here, but expecting about 0.50-1.00 liquid equivalent. On the higher end of that range in Greater Lynchburg and north toward the lower end across Southside Virginia.
Feel pretty good in areas north of the Staunton River and Smith Mountain Lake that there will be at least be a thin coating of ice on elevated surfaces (tree limbs, power lines). But there may be more, depending on
Most critical will be the temperature when the precipitation is at its strongest. This will be governed by how dry the air is here at the ground on Saturday (we use the dew point temperature to measure the amount of absolute moisture in the air).
As precipitation falls into the dry air, there is cooling of the air, but a rising of the dew point. The temperature at which these meet is called the wet bulb, and the wet bulb would be the temperature at which the heaviest precipitation will fall.
While we can have freezing rain at 31F, that ice tends to be soft and does not usually cause big travel impacts during daylight hours, as there is still some solar energy getting through the clouds. But freezing rain at 26F is a different story. Ice is harder and poses more of a transportation hazard.
Right now, that wet bulb temperature appears like it will be in the middle to upper 20s, but a small break in that number in either direction has large repercussions on the amount of ice on surfaces.
The places at greatest risk of large ice accumulation are north and west of Lynchburg. These counties for example: Albemarle, Alleghany, Amherst, Augusta, Bath, northern Bedford, Botetourt, Craig, Floyd, Nelson, Rockbridge. These locations will likely be coldest the longest and have the most precipitation.
Lowest Risk Areas
We do expect some ice as far south as the northern counties of North Carolina. But precipitation amounts will probably be smaller and temperatures will be a few degrees higher in Charlotte, Halifax, Henry, and Pittsylvania Counties. This includes Danville. Even there, however, the storm should be followed closely over the next few days.
The remaining areas could have anything between a small nuisance or a 1-inch coating on surfaces. At this point, it is still too far in advance to tell with any certainty. Those remaining areas include the following counties: Appomattox, southern Bedford Buckingham, Campbell, Franklin, Montgomery, Patrick, Prince Edward, Roanoke. This includes Lynchburg and Roanoke City.
As always, it is imperative to remember that this is a forecast made 4 days before the precipitation begins. So expect changes and modifications in the forecast.
Small changes in temperature and precipitation amounts have large real-world effects on travel, vegetation, and the electric grid.