This week, with 60-degree-plus weather predicted for Christmas Eve, you might feel a little guilty if you’re enjoying it and be asking yourselves if this is climate change at work. When the weather gets weird we often have strong reactions to what’s happening out there.

Would There Be Snow If We Didn’t Have Cars?
The title of this paragraph might seem silly, but if you believe this December’s weather is caused by climate change you could think that. It may seem logical that if somehow humans hadn’t spewed trillions of metric tons of carbon dioxide into the atmosphere over the past century, this would be a cold and snowy December as had been the case in the past, right?

Of course, climate change isn’t responsible for our warm December and there have been many snowless years before. Rather this is connected to a strong El Nino and the fact that the polar vortex is whirling around the top of the planet so fast the cold air can’t get out and escape south.

Yes, that pesky polar vortex, which had so much media hype in the previous two winters for bringing unusual cold, is now partly to blame for the unusual warmth. A strong polar vortex lessens the opportunity for arctic air here.

polar ao

El Nino, which is simply warmer than average in the equatorial area off Peru, is adding a lot of heat to the atmosphere. It’s peaking right now and it’s also going to spike the global temperature this year.

anomnight.10.12.2015

A more accurate way to think about how anthropogenic climate change is playing a role in our weather is that without humans, perhaps the high temperature forecast on Thursday would be a degree or two cooler. But the deer wouldn’t be trudging through mountains of snow. Over the coming decades climate models do predict fall-like weather extending later and spring-like weather arriving earlier. But there’s a lot more research needed into individual weather events and climate change.

Nearly three-quarters of the U.S. population will be experiencing temperatures over 60 degrees on Thursday. Records will fall from Florida to Maine and the Currier and Ives image of a white Christmas will be just that, an image, not reality.

records will fall

It’s been a warm month. While we still have more than a week until New Year’s Eve, the likelihood of this being the warmest December on record for much of the East and certainly here in New England is extraordinarily high. Parts of Maine could also see their warmest December on record and one of the least snowiest.

Not only will we break the record, but we may shatter it by 2 or more degrees. Typically, record warm months are broken in 10ths of a degree.

Notice below that the spread between the warmest Decembers on record is quite small. Presently our mean temperature is a whopping 38.9 degrees and while this will fall a bit, it’s likely to rival or exceed 2006, currently the warmest December.

pwm warm decembers

Good, Bad or Indifferent?

For some individuals and industries this has been a bad month. Retailers like some cold and snowy weather to get folks buying winter gear. That hasn’t been the case. Ski areas have even had trouble making snow, but some northern areas are open and have skiing.

With heating costs so much less than last year, this month’s warmth is only adding to our savings over the previous winter.

Coming Attractions
Future El Nino events may be stronger and the typical oscillations we observe may be altered, but you can go ahead and enjoy this warm week, keep the window open while you are sleeping and maybe even play a round of golf. The weather is going to turn colder in January and that’s for sure.


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