On Monday, temperatures in Washington are set to soar well into the 60s. But two days later, the region could see its first snowfall of the season (not counting the flurries last week).

A strong cold front will pass through the area late Monday, knocking temperatures back about 25 degrees by Tuesday. Then, on Wednesday, a weak storm system is expected to move in from the south with enough cold air in place for the chance of snow.

Computer models vary on the intensity of any potential snowfall, and temperatures (near to a little above freezing) will be only marginally cold enough to support frozen precipitation. In other words, the chance of accumulating snow is rather low but will increase some toward the mountains, especially along and west of Interstate 81.

Right now we’d put the odds of an inch or more within a one-county radius of the District at around 20 percent, but they increase to around 40 percent in Loudoun and Frederick counties and perhaps 60 percent along I-81, including spots such as Front Royal, Winchester and Hagerstown.

In the immediate metro area, primarily non-accumulating light snow seems most likely. Timing-wise, while subject to change, snow could begin around sunrise or a little before and continue intermittently through the morning, before tapering off in the afternoon.

Overall, we’d lean toward this being a nuisance event with minimal impact. However, there’s an outside chance that, if the snow comes in early enough and falls at a steady clip, the morning commute could be slick, especially in our colder areas north and west of Washington.

As the potential system is still three days away, forecast specifics could change, and scenarios range from no precipitation to a moderate, accumulating snowfall. There’s also a small chance that, if the storm track shifts north, more rain than snow falls.

What do the models say?

Computer model forecasts tend to fall into two camps. One camp, presented by the American models (the NAM and GFS), forecasts a stronger system and would suggest a period of steady snow and some accumulation on Wednesday. The other camp, presented by the European (ECMWF and UKMET) and Canadian models, projects a weaker system passing well south of Washington that would probably mean only light, non-accumulating snow, if any.

If we look at the raw output of the different models, here’s how much snow they forecast for Washington:

  • NAM: 2 to 4 inches.
  • GFS: Around 6 inches.
  • ECWMF: 0.1 inches.
  • UKMET: No accumulation.
  • Canadian: 0.4 inches.

Since air and ground temperatures will probably be above freezing at times Wednesday, the accumulations predicted by the NAM and GFS models make the incorrect assumption that all snow will stick. If we correct for that, actual totals would probably be about 25 percent lower.

Right now, we lean more toward the European and Canadian models but will revisit the forecast and update our thoughts on Monday.