One of the year's finer stretches of weather is underway, so you might well want to stop reading about here.
In its annual winter forecast released Wednesday, AccuWeather Inc. is calling for slightly above-normal snowfall and a February that would be about 9 degrees colder than last February.
January would average about normal, and, in accord with outlooks by at least two other major forecast services, AccuWeather is calling for a mild December.
El Niño warming in the tropical Pacific is a factor in the winter forecasts by all three of them. Weather generally travels west to east, and when sea-surface temperatures out that way are significantly above normal, they can have a powerful effect on North American winters.
The forecast problem this time around is that El Niño has been slow to take hold, although the Climate Prediction Center still says it is likely that it will be brewing during the winter.
Paul Pastelok, AccuWeather's long-range forecaster, said he believes it will be weak one. Even it becomes strong, its influence around here would be uncertain. Winter outcomes during El Niños and their opposites, La Niñas, have been decidedly mixed.
"Some of them haven't worked out the way they were supposed to work out," he said.
Another complication is the strange temperature pattern in the North Atlantic, which isn't a pattern at all, with a mix of warm and cool surface waters. He said the fact that temperatures are warmer near the East Coast and 3 to 5 degrees above average across the Great Lakes argues for a warm December in the region.
Those warmer waters would mean more cloud cover in December, which would prevent the nights from getting too cold, thus bucking up temperatures.
That will change as the winter progresses, Pastelok says: December temperatures in Philadelphia will average about 2.5 degrees above normal in December, near normal in January, and as much as 3 below in February.
All of this comes with extreme caveats. The early atmospheric clues aren't particularly telling, and seasonal forecasting remains quite an elusive pursuit. Last year, for example, AccuWeather saw a "chilly winter" for the Mid-Atlantic and Northeast. It did not — nor did any other forecast — foresee the stunning warm February in which Boston, New York, and other cities set records.