United States

Updated Winter Forecast Model is Stormier in the East

December 10, 2012; 9:33 AM

The new updated ECMWF model forecast for the three months of January, February and March combined was just released to our in-house systems this weekend. This seasonal model is updated just once a month and also forecasts out through the spring of 2013.

ECMWF model forecast temperature anomalies for the period of Jan.-March 2013.

ECMWF model forecast temperature anomalies for the period of Jan.-March 2013.

My estimate of the mean jet stream (steering flow) for the Jan.-March period strictly based off of this particular ECMWF model run.

This forecast model has trended stormier from the Ohio Valley into the northeastern U.S. and up through eastern and Atlantic Canada for the remaining winter months of January, February and March combined, which could be good news for skiers, snowboarders, snowmobilers and winter resorts across the interior Northeast and up into eastern Canada.

The western Canadian ski resorts are already off to a very good start to the season. The updated forecast model shows typical winter conditions on average from January through March, but with solid bases as we speak, we should expect a great ski season. Of note, the model has backed away from the persistent dry look it had from earlier runs over western B.C. and the Pacific Northwest, which is not that surprising since the earlier idea of a potential weak to moderate El Nino for the winter is no longer on the table.

Atlantic Canada looks mild, but stormy according to the latest ECMWF run and I agree with that.

One surprise for this update was the colder than normal temperatures showing up around the Great Lakes. If that idea is correct, and considering the expected jet stream pattern we could be looking at a significant uptick in lake-effect snow in January and February, especially since the lakes are still running warmer than normal.

Too hard to say what type of precipitation will dominate, but if the ECMWF has the general pattern right then I would lean toward more rain than snow along the East Coast and up into coastal Atlantic Canada, while snow would be favored on average from the northern Ohio Valley through the interior Northeast and up into Ontario, Quebec and New Brunswick.

The model has more of a -AO (negative Arctic Oscillation) look to it for this three-month period as it appears that the polar vortex is shifted farther south away from the pole and into north-central Canada. This usually ends up forcing the coldest air farther south than normal, while the region around the pole see's above-normal temperatures.

Again, keep in mind this is just one model and it is the extended long-range, but it is the model with the highest skill on average compared to the rest of the long-range models.

I will keep you posted as usual. You can also follow me on twitter @BrettAWX.

The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or AccuWeather.com