“But where are the snows of yesteryear?” That’s the slightly rough translation of a “ballade” by French poet Francois Villon written in ... 1489!

Here we are, 11 days into January, there’s barely any snow on the ground, and our major lakes are just now freezing over, several weeks later than usual.

Even though our recent daytime highs have been seasonably chilly, the overnight lows remain above normal. In fact, the overall temperature has been above normal for the past 21 days, since Dec. 20, according to the government’s automated weather station at Pittsfield Municipal Airport. On seven of those days, the departure from average has been extreme, in the double digits.

A reminder: We’ve just entered the coldest two-week stretch of the year in Berkshire County, with a historical normal range from 11 to 29. The outlook for the week ahead shows more above-average readings every day, especially mid-week and beyond. As for snow, we’ve only had 3 inches since Dec. 17, the day after the 14-inch storm that whitened our landscape and brought out the snowplows for the first and only time this season, so far. But the snow was washed away by the springlike rainfall (1.3 inches) along with the 56 and 61 degree highs on Christmas Eve and Christmas Day.

Here’s the explanation for the bizarre winter so far. The so-called polar vortex, a huge swirl of extreme frigid temperatures, has been split in three because of a climate-change phenomenon called Sudden Stratospheric Warming over the Arctic. Some parts of the U.S. South and northern Europe, including the British Isles, have been infiltrated by chunks of the vortex, while the Northeast has been spared.

But that’s about to change, as reported by livescience.com, which puts it in simple terms: “High above the North Pole, the polar vortex, a fast-spinning whirl of frigid air, is doing a weird shimmy” tied to the rapidly warming Arctic climate.

“Expect a more wintry back-half of winter here in the Eastern U.S. than what we had in the first half,” said Judah Cohen, director of seasonal forecasting at Atmospheric Environmental Research, based in Lexington.

The Arctic is heating up faster than any other region in the world, and that’s likely to be throwing the polar vortex out of whack, Cohen said. The effects of the sudden, high-altitude warmup may be felt in New England within two weeks, likely around Jan. 19, when the displaced polar vortex shows up, accompanied by much colder air, snowstorms, or both.

For the week ahead, benign is the word for Berkshire County weather, with no storms in sight and very little change day to day. Some sun, some clouds, with only the slightest chance of a snow flurry in the current forecast.

Nationally, a shot of cold air for Texas, the Southern Plains and the lower Mississippi Valley is expected on Monday. Heavy rains and mountain snow continue in the Pacific Northwest during the week, while the Great Lakes region may see some snow by Friday. Next weekend could shake up the dry weather pattern over the Northeast.

Unusually mild temps continue from Montana to the upper Midwest, especially mid-week, while the West warms up by next weekend, with possible record highs in some parts of the Southwest and California.

Meanwhile, the darkest days of the season have passed by. This week, sunrise slowly gets earlier, with a gain of a half-minute each morning, while sunset is a minute later day by day. We’ve already picked up 20 minutes of afternoon daylight after Christmas as the midpoint of “meteorological winter” approaches next weekend.

The Outlook is today's look ahead at the week's weather, its impact on the Berkshires and beyond. Clarence Fanto can be reached at cfanto@yahoo.com.