A light wintry mix sliding into the Washington region Sunday evening could cause pockets of slick travel, lingering into Monday morning.
Then, a second round of mixed precipitation could develop Monday night into Tuesday morning.
For both of these waves of wintry precipitation, snow accumulation and iciness are most likely in colder areas north and west of downtown Washington.
We do not expect temperatures to be cold enough for widespread iciness from either wave in the immediate metro area. However, slick spots on untreated surfaces are possible. Both pedestrians and motorists should be prepared for patchy iciness and use caution.
The first wave: Sunday evening into Monday morning
A mix of snow, sleet and freezing rain is likely to develop Sunday evening, from west to east. We can’t rule out some patchy light snow or sleet as early as late afternoon in our western areas. Initially, temperatures should be above freezing — minimizing impacts.
However, as Sunday evening wears on, temperatures will fall near or below freezing, with the coldest north and west of downtown. Any snow that falls is likely to transition to a mix of sleet and freezing rain overnight Sunday into early Monday morning, especially from the Beltway south.
Snow accumulation should be light, around a coating to an inch in most areas, except one to three inches into northern Maryland. Regardless of how much snow falls, a coating of sleet and freezing rain could also result in slippery travel. Conditions should generally deteriorate as you head into our northern and western areas.
Untreated roads, sidewalks, parking lots and driveways may be slick. Motorists should use particular caution on bridges, ramps and overpasses.
This wintry mix should taper off on Monday morning and transition to plain rain, as temperatures rise above freezing in most areas. However, some school delays and impacts on Monday morning’s commute are possible.
As shown in the map above, the best chance for widespread snowy/icy conditions falls in Zone 1, from northern Maryland to northwest Virginia, where temperatures may fall to around 30. Some areas of iciness are possible in Zone 2, where temperatures are forecast to bottom out around 31 or 32. The chance of slick spots in Zone 3 is more iffy, with temperatures right around 32 or 33.
The second wave: Monday night into Tuesday morning
The next wave of precipitation may develop over the region Monday afternoon and evening. Initially, temperatures should again be above freezing in most areas, so we don’t expect big problems with the Monday afternoon commute at this point. Precipitation may begin as a mix of snow and sleet and — in our milder areas from downtown to the south and east — rain.
As colder air feeds south Monday night, the wintry mix could start accumulating in our colder areas north and west of downtown. However, models differ on exactly how cold it will get.
Some models suggest temperatures will generally remain above freezing, and any mixed precipitation will transition to rain. Others predict temperatures will drop to around freezing in our colder areas. Like the event Sunday night into Monday morning, Zones 2 and 3 (in the top map) have the best chance of seeing some iciness develop.
During the day Tuesday, temperatures should rise, but it may be a slow process. This means our colder areas could hang on to some iciness if it materializes Monday night. Most other areas will likely just have cold rain.
We’ll have another detailed update on these two rounds of wintry precipitation on Sunday.