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National Weather Service to define new 30 year climatology

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(WQOW) - Weather is always changing, and that includes what is considered to be the average. Soon, the National Weather Service, with the help of the National Climatic Data Center, will be determining the new "normal."

When you hear meteorologists talk about average temperatures or average snowfall, they're actually only talking about the average over the most recent 30 year period. Right now, our averages are based on data from 1981 to 2010, but once 2020 is over, the new 30 year average will cover 1991 to 2020.

National Weather Service Meteorologist Eric Ahasic said warming trends over the past several decades will likely cause average temperatures to be one or two degrees higher each month with the new climatology, with the biggest increases during the summer months. He also said nighttime temperatures have increased more than daytime temperatures.

"We started this very noticeable and pronounced up-trend with temperatures at most sites," Ahasic said. "It kind of started in the 80's, but it really took off in the 90's, and then especially in the 2000's."

The current climatology does not include recent precipitation extremes including 2019's record snowfall. Additionally, this is the fourth consecutive winter in a row with above average snowfall. It will all be factored into the new climatology.

"We will probably start to see more below normal months once we switch to that new data set just because all the averages have gone up," Ahasic said.

He said even though the averages change over time, it doesn't affect the actual temperature record.

"The day-to-day temperature data is just gonna keep on going. That's not any different," Ahasic said. "It's just what you're regulating it off of is changing."

The information is used in a variety of ways, including establishing a new definition of the average growing season and determining energy use.

The NWS said it may take a few months after 2020 ends to review the data and implement the new baseline.

Jess Langlois

Jess Langlois is the weekend meteorologist and weekday multi-media journalist for News 18. She joined us in July of 2019.

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