Few would argue that the opening two weeks of November have been downright brutal in the temperature department, and the statistics unequivocally back that up. Temperatures over the first 14 days of the month have averaged a bone-chilling 29.4°. That's nearly 14° PER DAY below normal, and the coldest open to November since 1991. In fact, November, 1991 is the only November to open colder than this year!
Cold spells aren't uncommon this time of year, though one of this duration is a bit more unusual. Our stretch of consecutive days with at or below normal temperatures has reached 24, and will undeniably continue to grow for several more days. So, just why have we been so cold for so long? There are many contributing factors in play, not the least of which being the expansive snowpack that's been laid down over the United States over the past several weeks.
As of Thursday, more than a quarter of the nation was snow-covered, 26.5% to be specific. Only two other years since 2003 have had snow covering more than the country on November 14 than this year. On average, about 13% of the country has been snow-covered on November 14 over the past 16 years. This is significant, because air has difficulty warming over snow cover, due to the highly reflective nature of the snow. Bare ground absorbs sunlight, allowing for warmth to occur more effectively, while snow cover reflects incoming sunlight, which greatly hampers warming.
The effects of the expansive snowpack here are twofold. Not only is the snowpack here inhibiting any significant warming, there's snow on the ground in virtually every direction. For that reason, no matter what direction our wind is coming from, our air is traveling over snow, which adds insult to injury. Any meaningful shift in the weather pattern won't likely occur until we're able to eradicate the snowpack here, and also to our west and south.
Earlier on, we mentioned how only 1991 featured a colder start to November than this year. While it would be logical to assume that the winter months that followed were cold and snowy, that surprisingly wasn't the case! In fact, the winter of 1991-92 was a remarkably warm one, the 9th warmest on record, with temperatures nearly five degrees per day above normal. It featured 28 days in the 40s or above, including two days in the 60s! Snowfall ended up below normal that winter, by nearly a half a foot. Of the 30.6" of snow that fell in the 1991-92 cold season, only 20.0" came between December and February.
While this is not by any means a guarantee of a mild, dry winter, it at least proves that dramatic pattern reversals are possible, and have occurred here in the past. If nothing else, it gives mild weather enthusiasts at least a shred of optimism.