An experimental version of the American (GFS-FV3) model shows light snow brushing Northern Virginia on Sunday afternoon, mainly south of Washington. (TropicalTidBits.com)

Every day this week, we’ve stressed how the Washington region straddled the edge of a winter storm coming up from the south on Sunday. Small shifts in its ultimate position, we’ve said, would make the difference between no snow, some snow and a lot of snow.

In the past 24 hours, forecasts for the storm have made a small but consequential shift to the south, cutting down the chance of accumulating snow in the Washington region. It’s not yet game over for snow but pretty close.

Whereas on Wednesday we gave a 35 percent chance of at least an inch of snow in the region, we’d drop that to 20 percent effective today. And that might be generous.

The chance of several inches or more is down to 10 percent or less.

Areas from the District north may not even see a flake (60 percent chance). Our southern suburbs probably have a 50 percent chance of seeing some light snow or flurries that could put down a dusting or so — mainly late Sunday afternoon into Sunday evening.

“The models have pretty much slammed the door on the possibility of a major snowstorm,” Capital Weather Gang’s Wes Junker said in an email.

He explained that the northern branch of the jet stream is just too strong and will not allow the storm riding along the southern jet stream to come far enough north.

“There still is a small chance we see light snow or flurries but even that probability is fading,” Junker said.

A heavy snowstorm for southwest Virginia (medium confidence) and western North Carolina (high confidence) remains in the cards, with over a foot possible.

But Washington may be lucky to see even a few flakes. Here is a summary of the model predictions for the Washington region, and it’s a sad state of affairs for snow lovers:

  • Operational American (GFS) model: No snow from the District north. Patchy light snow or flurries possible in our southern suburbs Sunday afternoon and evening. Little or no accumulation.
  • Experimental American (GFS-FV3) model: No snow from the District north. Patchy light snow or flurries possible in our southern suburbs Sunday afternoon and evening. Little or no accumulation. Just 48 hours ago, this same model was forecasting 15 to 20 inches and, 24 hours ago, 3 to 6 inches for the Washington region.

The experimental American (GFS-FV3) model shifted the predicted position of Sunday's storm south each of the last two days. Forecasts for a lot of snow on Tuesday dwindled to little or no snow as of Thursday. (TropicalTidBits, adapted by CWG)
  • Canadian model: No snow within a two-county radius of the District. Light snow and flurries possible late Sunday afternoon into Sunday night from Fredericksburg south. A day ago at this time, this model was forecasting a major snowstorm for the Washington region.
  • European model: No snow within a two-county radius of the District. Light snow and flurries possible Sunday night from Fredericksburg south.

The models described above represent the primary predictions in larger modeling systems that contain dozens of simulations. But even among this larger group of projections, the percentage of simulations that forecast substantial snow has dropped dramatically.

For example, the European modeling system, which contains 50 simulations, has really backed off snow prospects for the Washington region. Of the 50 simulations:

  • About 70 to 75 percent predict no snow.
  • Only 25 to 30 percent predict at least a dusting.
  • Only 10 percent predict at least two inches.
  • Only one simulation (2 percent) predicts at least 6 inches.

European modeling system predicts just a 10 to 20 percent chance of an inch of snow in the Washington region Sunday into Monday. (WeatherBell.com)

The American modeling system still does hang on to a 10 percent chance of a big storm (of at least 6 inches) and a 40 percent chance of an inch.

Models could still jog the track of the storm back north a bit, which would increase the chance of at least some light snow in the region. This is something we’ll continue to monitor.