The National Oceanic and Atmospheric Administration (NOAA) released its winter outlook on Thursday. This year's forecast has proven to be a difficult one, with one NOAA director calling it "one of the most challenging outlooks" in recent years.
Here in Western Massachusetts, NOAA believes the forecast is virtually a toss-up, with equal chances of above or below normal snowfall. Bradley International Airport, the official climate station of the Pioneer Valley, averages 49.0 inches of snow per season.
"El Nino decided not to show up as expected," said Mike Halpert, deputy director of NOAA's Climate Prediction Center. "In fact, it stalled out last month, leaving neutral conditions in place in the tropical Pacific."
What this means is a winter outlook that is less confident than past years where a strong presence of El Nino or La Nina is occurring.
El Nino is a warming of ocean waters in the equatorial Pacific, which causes shifts in large-scale jet stream patterns and evolution of Pacific storms. These climate shifts have been documented to have certain impacts on the United States, such as a typically warmer and drier winter for the western United States. The no-show of El Nino this year obviously raises doubts for their forecasts.
For Western Massachusetts and the Northeast U.S., a greater player (although more unpredictable player) for New England winter forecasts is the North Atlantic Oscillation (NAO), which is a measure of pressure differences between the Icelandic Low and the Azores High.
For example, when the NAO is in a positive phase, it is more difficult for Arctic air to plunge southward and into the Northeast, which may cause more of a rain/mix storm instead of supplying enough cold air for an all-out snowstorm.
On the other hand, a negative NAO can lead to more numerous cold snaps during the winter for us. However, NOAA cites that this oscillation can be difficult to predict just a few weeks out, let alone for an entire season.
NOAA's complete winter outlook for the entire United States can be found on the CBS3 Pinpoint Weather Blog.
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