Thursday is looking like a mess across the DC Region as another potent, moisture-rich, winter storm moves our way. All of the forecast models start the DC area with accumulating snow Wednesday night through Thursday morning before a change over to either sleet or freezing rain occurs. There is the potential for significant accumulations of snow, sleet and freezing rain.
GFS Ensemble (American) showing 30 ensembles (opinions) for snowfall potential:
Next up is the Canadian ensemble model which shows quite a spread in snowfall accumulation:
Snow will develop from southwest to northeast during the pre-dawn hours early Sunday morning. Snow may fall heavily at times between 3AM and 11AM Sunday before tapering off and ending as flurries between 12 and 3PM.
Due to the overnight timing and heavier nature of the precipitation, this will be one of those wet snows that cover all untreated surfaces and will be great for making snowmen and snowballs.
In a rather rare turn of events, it appears that the Metropolitan Area has the best chance of remaining all Snow and receiving the heaviest accumulations. Sleet may mix in with the snow across southern Maryland and the northern neck of Virginia.
Despite current temperatures hovering just above freezing — dew points are currently hovering in the lower 20s and evaporation cooling will likely cause surface temperatures to drop during the PM rush, allowing for a period of moderate to heavy snow or sleet to fall across the Metropolitan Area.
The latest high-resolution rapid refresh model (images below courtesy WxBell) paints an interesting picture for those of us snow-starved DC Area residents. The image below begins at 20z (3pm) and continues through 7z (12am). Notice the dark blue representing heavy snow, orange (sleet) and pink (the dreaded freezing rain).
Most models depict the snow and sleet to break out in earnest between 3 and 6pm,just in time for the afternoon rush hour.
Temperature profiles in the mid-levels of the atmosphere are tricky today and snow or sleet could easily accumulate this evening especially along and north of the interstate 66 corridor in Northern Virginia and along and north of the route 50 corridor in central Maryland. The image below is from the latest High Resolution Rapid Refresh (HRRR) model and shows that there is at least a potential for an inch or two of snow even in the immediate Metro Area (to include the District).