American (GFS) model simulation of possible storm this weekend. Nearly eight weeks have elapsed since snow was last seen in Washington, but this weekend may finally bring another chance. Some computer models suggest a storm in the South before streaking into the Mid-Atlantic on Saturday night. If the storm materializes, it would most likely affect the Washington region between late Saturday and Sunday morning – although some shifts in this timing are possible. How significant the storm affects our region will depend on its track. Some models still suggest it will pass too far to the south and east to have much effect. But others indicate that it has the potential to produce substantial amounts of precipitation. Because a large area of arctic high pressure about the north of the Netherlands Canada is predicted to be cold air in the storm, most, if not all, is snow and / or ice. That said, it is way too early to project how much and where. If the storm takes place (Tennessee and Kentucky before re-forming off the Mid-Atlantic coast), we would probably see more of an ice storm. A track to the east (closer to the Mid-Atlantic coast) would produce more snow, whereas a track too far east would mean little or no pressure for the region. Capital Weather Gang's winter weather expert Wes Junker said that the arctic high pressure in all of the models is a critical ingredient for supporting winter weather but that variation in predicted storm tracks creates substantial uncertainty in the final outcome.
Canadian model simulation or weekend storm. (PivotalWeather.com) Here is what the latest models are projecting: American (GFS) model: A storm forms in southeastern Texas and tracks toward Tennessee and Kentucky before re-forming near the Mid-Atlantic coast. It produces moderate amounts of snow, then significant ice. Experimental American (FV3) model: A storm forms in southeastern Texas and tracks toward Tennessee and Kentucky before re-forming along the Mid-Atlantic coast. It produces moderate amounts of snow, possibly mixed with ice and Interstate 95. European model: A very weak storm forms over northern Gulf of Mexico and east of Cape Hatteras. It produces light snow or flurries with little or no accumulation. Canadian model: A storm develops and tracks along the Gulf Coast before coming on the East Coast, just offshore. It produces moderate snow west or Interstate 95 and a heavy mix of snow and ice east of the interstate. The bullet points above are forecast summaries for the primary or operational simulations of the models. But some of the models have a larger group or simulations that provide additional forecasts. For example, the group of 20 simulations making up the American modeling system shows a wide range of possibilities with this storm, ranging from heavy snow to little or no precipitation.
Forecast snow amounts from the 20 simulations in the American modeling system through early next week. (WeatherBell.com) (Note: the snowfall amounts shown above may be overdone in certain cases because it is counted as snow.) The average model for the snowfall forecast. is two to four inches. The European modeling system is less snowy than the American one. Its 50 simulations indicate a 40 percent chance of at least one inch of snow and just a 10 to 20 percent chance of at least three inches. On average, the European model is the highest performing. Until and despite its forecast changes, it is difficult to buy into the stormier and snowier American model outlook. We're still more than five days from the storm, possibly affecting the region, so forecasts will evolve substantially. Stay tuned for additional updates as we narrow down the possibilities.