ADDISON COUNTY — Those who wonder if this past Monday morning’s freak windstorm was unusual or just the latest extreme weather in Addison County this year have good reason to do so.
Consider the following:
•  The average temperature in October in Burlington through Oct. 30, according to the National Oceanic and Atmospheric Administration (NOAA), was 58.6 degrees — 10.5 degrees warmer than typical and about 2 degrees warmer than the previous record for the month.
Folks outdoors found themselves peeling off layers as late as Oct. 24, when temperatures reached a daily Burlington record 78 degrees, and two days later, when it hit 69.
•  Eight of 10 months in 2017 in Burlington have seen above-average temperatures, including January, with an average temperature that was 29.7, 11 degrees above the norm NOAA established by averaging monthly January temperatures since 1980. February followed by averaging 8.3 degrees above typical.
•  Snowfall was below average until March, when a whopping 36.8 inches fell, 21 inches above the norm for the month, mostly in one huge mid-month storm.
•  Rainfall exceeded the norm in every month between April and July, frustrating farmers who often found themselves looking out at fields of mud. June’s rainfall of 7.19 inches in Burlington was about 4.5 inches above average.
According to National Weather Service meteorologist Peter Banacos, who operates out of NOAA’s Burlington office, each of these weather events can be traced to larger patterns.
For example, in January and February a strong flow of air across the United Stages stopped colder air from moving in the north.
“We had a fast west-to-east flow across the continental United States, so a lot of Pacific airstream was coming straight across the country,” Banacos said. “So that sort of prevents the Arctic air that’s locked in the northern reaches of Canada and the Arctic from being able to come southward. Or if it does come southward it’s just a very brief intrusion of cold air.”
That flow also blocked a lot of snowfall, at least until March. Then, about two-thirds of the month’s snow fell in 24 hours as the pattern changed drastically. March also saw the year’s only below-normal average temperature, 27.4 degrees compared to the typical average of 31 for the month.
“In March, of course, we had the big storm on the 14th that dropped a couple of feet of snow, so we did briefly get into more of a blocking pattern where we had a ridge across Greenland and more of a trough across the Great Lakes and the northeastern United States,” Banacos said. “So with that change in the pattern we had colder air right at the end of winter, basically.”
That trough stayed in place and helped cause early spring precipitation, which Banacos said was later further fueled by upper level troughs stalling out over the Northeast through the spring, a more common phenomenon.
“We did have a pretty wet period,” he said.
July and August proved to be more-or-less typical. July’s temperature was exactly average at 70.6, and rainfall was just a half-inch more than normal at 4.16 inches. August was a bit warmer (69.4 degrees compared to the average of 68.8) and wetter than usual (3.91 inches of rain, more than the typical 2.4), but within normal variations.
Then came steamy September and October. Banacos said stubborn high-pressure off the Atlantic coast locked in the unseasonal warmth for about six weeks before “west-southwesterly flow from the Great Lakes” finally dislodged the pattern.
“The thing we’ve had more recently is a large upper-level ridge along the Eastern Seaboard of the U.S. It’s kept us pretty warm and until recently pretty dry as well,” he said. “We just went a long time without developing any pattern change.”
Banacos said meteorologists are still working on why patterns over the Northeastern U.S. can sometimes change quickly and at other times remain in place for so long. He said New England forecasts are only good for 10 to 14 days, while at times his colleagues in the Southeast can look months ahead — yes, it’s true our weather is more fickle and less predictable.
“It’s hard to say the causality for that. But sometimes we get locked into these patterns for several weeks or even a month or two before it breaks out of it. And the exact reasons why are not always well known,” he said. “But you tend to get into persistent patterns like we saw in the winter and that we saw more recently in September and the first half of October.”
But the data can be telling over the long term. The Burlington NOAA station has kept average monthly and annual temperatures since 1980. The average annual Burlington temperature coming into 2017 stood at 46.2 degrees.
Every year since 2012 has exceeded that figure:
•  In 2012, the average temperature was a record 49.9 degrees.
•  In 2013, 47.1.
•  In 2014, 46.4.
•  In 2015, 47.1.
•  In 2016, 49.2.
“The overall trend is warmer. There’s no question about it if you look at the data,” Banacos said.
The average temperature so far in 2017 is 52.5. That 10-month average trails only record-setting 2012’s average of 53.1 through 10 months. And WCAX-TV reported on Tuesday November is expected to be warmer than normal, and its Wednesday morning forecast pegged daily highs on Thursday, Friday and Monday to be at around 60 degrees.
Banacos said it’s not out of the question 2017 could end up as the hottest year on record in Burlington, while it looks like a shoo-in as the runner-up.
“We’re a little bit off the pace, but it is on the higher end. It’s looking like the second-warmest we’ve had since 1980,” Banacos said. “We’ll see how it ends up in the next couple months here.”
Andy Kirkaldy may be reached at [email protected].