The Washington PostDemocracy Dies in Darkness

Super Bowl Sunday storm could bring mess to Mid-Atlantic

A cold rain is most likely, but some wet snow could fall, especially toward the mountains

Wednesday morning GFS weather model run, forecast for Super Bowl Sunday evening. (Pivotal Weather)
4 min

It’s been a historically quiet season when it comes to winter storms in the Mid-Atlantic, but February is often the peak month for snowfall. As such, it’s too soon to let our guard down for some of the white stuff, even amid a generally mild weather pattern.

Computer models do show the possibility on Super Bowl Sunday of cold rain, possibly mixing with or changing to wet snow at times — especially in colder parts of the D.C. and Baltimore region. But rain is most probable, with any significant chance for meaningful snow reserved for mountains to the west.

New York City sets record for lack of snowfall

A storm system is projected to develop off the Southeast coast Saturday into Saturday night. On Sunday, it is expected to move northeastward while intensifying and throwing precipitation westward before heading offshore Sunday night.

How far offshore and how far north the storm travels are key.

The best odds for heavy precipitation span from southern Georgia into the eastern Carolinas and southeast Virginia. Some heavy precipitation could spread into the rest of Virginia as well as the District, Maryland and Delaware, but confidence in how far north and west the precipitation reaches is low.

Rain is likely to be the primary precipitation type. But accumulating snow could fall on the west and northwest edge of precipitation.

Storm track will determine how much precipitation and where

Washington and locations to the north may see heavy precipitation or may just get skirted by some lighter rain. Forecast models in the last 24 hours have tended to shift the track of the storm somewhat farther north and west, increasing the odds of precipitation around Washington and Baltimore.

“[M]oisture wrapping around the well developed low now has potential to produce wrapback heavier weekend rains and enhanced winds from the Southeast to at least the eastern Mid-Atlantic and coastal New England,” the National Weather Service wrote early Wednesday morning.

Although model forecasts have shifted farther north and west with the storm track, that trend may not persist and could even reverse — meaning lesser impacts. We see three plausible scenarios, with the first two perhaps most likely:

  • The storm tracks close to the coast. A track along the South Carolina coast to near Cape Hatteras and then to the northeast could bring heavier precipitation up the Interstate 95 corridor into the Washington-Baltimore area on Sunday. The I-95 corridor would probably see mostly rain, but colder areas to the west and southwest could transition to wet snow, especially into the Appalachians.
  • The storm fringes the big cities. A track farther offshore could limit precipitation in the big cities, favoring heavier amounts in areas east of I-95 and especially over the Carolinas and southeast Virginia. Snow accumulation would mostly be confined to mountains of western North Carolina and southwest Virginia.
  • The storm doesn’t come together and is out to sea. Several high-altitude weather disturbances need to mingle to create the storm. If they do not, a meaningful storm wouldn’t develop, and mostly dry weather would prevail north of the Carolinas.

To snow or not to snow?

While some snow cannot be totally ruled out east of the Appalachians, cold air is so limited that meaningful accumulation away from the mountains is improbable.

Northeast confronts weather whiplash, with record warm-up after record cold

“Accumulating snow around Washington is still a long shot as the low-level temperature is likely to stay above freezing,” wrote Wes Junker, Capital Weather Gang winter weather expert. “There is no cold air source.”

In an ideal situation for snowfall in the coastal Mid-Atlantic, a strong high pressure to the north would feed cold air into the area as a storm develops offshore. In this case, there is minimal high pressure and generally above normal temperatures across the entire Northeast into Canada.

For snow in the D.C. area from this event, the storm would have to follow a track so that a small pool of chilly air at high altitudes and heavy precipitation pass directly overhead. In that scenario, through a process known as dynamic cooling, rain could mix with or change to wet snow for a time.

“We would need heavy precipitation to fall with a perfect track,” wrote Junker. “The best chances for accumulations would be where elevation keeps temperatures a little colder and around I-81.”

The potential storm would come after several days of high temperatures near and above 60 in Washington and Philadelphia, with highs well into the 50s north of these areas. It’ll also be followed by warm air in the days after it passes.

January’s warmth was unprecedented in much of the Northeast

For now, the bottom line is there’s no major cause to worry that a significant snowstorm will heavily disrupt Super Bowl Sunday plans. Rain could certainly pester a wide swath. Details on the storm and its potential should become clearer in the coming days.