As Williams’ unofficial meteorologist, I have already received a plethora of questions regarding this upcoming winter – “when’s it going to snow?” being one of the most common. Or, “why is it so cold; it’s only October!” While I’m not ready yet – as it is still only October – to release a complete winter outlook, I have been looking at all of the most recent long-range models, talking with meteorologists, and, I will admit it, nervously guessing, in order to come up with a November outlook. Don’t despair, as my complete winter outlook isn’t too far away.
November is recognized as often being a difficult month for meteorologists to predict. Why? It is a month of upper-air battles between mild fall air and much colder arctic air. This November is proving to be no exception. In fact, as I talked with chief meteorologist Dr. Joesph D’Aleo of Weather Services International, he cautioned that there are “some indications that we will see more roller coaster temperatures as we alternate between mild and cold.” But there will be plenty of sources for cold air outbreaks in November: We will be in a near-neutral El NiÃ±o state (meaning neither El Nino nor La Nina) which would imply cooler than normal temperatures over the Great Plains region. With no climatic forcing in the Northeast from El Nino, we have to rely on a mode of climate variability called the North Atlantic Oscillation (NAO).
The NAO, is the dominant mode of winter climate variability over the United States. The NAO is a large-scale oscillation in atmospheric pressure between a milder subtropical high and a colder polar low. When the value is negative, as models suggest, there is a strong tendency for a trough of low pressure to settle over the eastern half of the United States allowing cold, Canadian air to simply and easily drop south into the continental United States. While expected to be negative for much of the winter, the NAO index does fluctuate on a weekly basis.
Thus, though I hate to be equivocal, as the atmosphere prepares to dive right into winter, and the battle between mild high pressure and cold polar lows begins, we will likely have both cold and milder stretches in November. However, from the way the atmosphere has been acting in October, it’s my personal contention that cold will prevail over milder temperatures in November. Thus, I am predicting slightly colder than normal temperatures with near normal precipitation. And now, of course, the all important snow question. I would be exceptionally surprised if we do not see some accumulating snow during November; during an “average” November in Williamstown, about 5 inches of snow falls.