Groundhog Says: 6 More Weeks of Winter! NOAA Says: Not So for the Southern U.S.

In Punxsutawney, Pennsylvania, home of the world's most famous prognosticating rodent, Punxsutawney Phil, gloomy clouds parted before sunrise on Friday morning, allowing Punxsutawney Phil to see his shadow. By tradition, the U.S. can thus expect to see six more weeks of winter. Phil’s fearless prognostication for the remainder of winter, as presented at his official groundhog.org web site, looks like this, then:

Up early this morning
Far from home
Are you searching for the Phil-ospher’s stone?
Well, even my best friends
They don’t know.
Is it an early spring
Or just more snow

My faithful followers,
Your hands (and my paws) are getting cold
So here is my forecast Not lead, but solid gold:
I see my royal Shadow!
Six more weeks of Winter to go!

Figure 1. Canada's famous albino groundhog named Wiarton Willy from the town of Wiarton, Ontario. Willie saw his shadow at dawn on Friday, so his prediction calls for six more weeks of winter. However, Nova Scotia’s Shubenacadie Sam didn’t see his shadow this morning from his little shed at a provincial wildlife park northeast of Halifax, and in New York City, groundhog forecaster Staten Island Chuck also failed to see his shadow, predicting an early end to winter. Image credit: wunderphotographer pincollector1.

Grading Phil's forecasts

According to the Punxsutawney Groundhog Club, Phil has seen his shadow on the morning of February 2 an inordinate number of times since 1886: 104 of the years, compared to just 18 years when he did not see his shadow (plus 10 years whose groundhog prognostications are lost in the mists of time).

Phil saw his shadow in 2017, predicting six more weeks of winter. Both February and March ended up warmer than average over the contiguous U.S. in 2017, so this was a blown forecast. NOAA’s National Centers for Environmental Information (NCEI) has analyzed Phil’s forecasts from 1988 – 2017. If we evaluate just the fifteen years when the departure of February and March temperatures from average over the contiguous U.S. were both of the same sign, Phil had five correct forecasts and ten blown forecasts, proving that it really isn't a 'bright' idea to use a groundhog's shadow in Pennsylvania as a predictive meteorological tool for the entire United States (dang!)
 

BREAKING: @ShubenacadieSam bit me. (Video online soon.) pic.twitter.com/vBIY4Yp25S

— Brett Ruskin (@Brett_CBC) February 2, 2018

Fun fact. The groundhog (Marmota monax) forecast is only valid in the native distribution range of the species. https://t.co/IOZaZF5kuO pic.twitter.com/GKpo3QuoEh

— Brian Brettschneider (@Climatologist49) February 1, 2018

How did this this crazy tradition start?

It all started in Europe, centuries ago, when February 2 was a holiday called Candlemas (much like Halloween and May Day, Candlemas is another ancient holiday positioned near the halfway point between solstice and equinox). On Candlemas, people prayed for mild weather for the remainder of winter. The superstition arose that if a hibernating badger woke up and saw its shadow on Candlemas, there would be six more weeks of severe winter weather. When Europeans settled the New World, they didn't find any badgers. So, instead of building wooden badgers, they decided to use native groundhogs (aka the woodchuck, land beaver, or whistlepig) as their prognosticating rodent.

The Groundhog Oscillation: convincing evidence of climate change!

According to a 2001 article published in the prestigious Annals of Improbable Research, "The Groundhog Oscillation: Evidence of Global Change", Punxsutawney Phil's forecasts have shown a high variability since 1980. This pattern, part of the larger "Groundhog Oscillation" or GO cycle, is convincing evidence of human-caused climate change.

Figure 2. Temperature outlook for February 2018, as predicted by NOAA's Climate Prediction Center (CPC) on January 31, 2018. A continuation of the cold in the north and warm in the south pattern is favored.

What the pros say

The latest long-range runs of the GFS and European models and NOAA’s 3 – 4-week temperature forecast agree on a continuation of the cold in the north and warm in the south pattern during February. The latest 3-month forecasts for February - April from Columbia University's International Research Institute for Climate and Society and from NOAA's Climate Prediction Center (CPC) show a similar pattern of cool in the north and warm in the south, but with warmer than average conditions spreading into the Northeast U.S. by March and April. Cold weather tends to shift westward across the northern U.S. as a La Niña winter progresses, so it wouldn’t be too surprising if the rest of the winter trended chillier in the Pacific Northwest and milder in the Northeast.

However, the long-range forecast for late February has more uncertainty than usual. A massive pulse of the Madden-Julian Oscillation (MJO) is currently over the Western Pacific. It’s the largest such event in 40 years of recordkeeping for the western Pacific, according to NOAA.  As this MJO pulse moves east through the Pacific, it may help drive a chain reaction of events, including severe cold over parts of eastern Canada, very mild air sweeping toward the North Pole, an unusually strong surface cyclone across the Arctic, and a split in the stratospheric polar vortex by mid-February. Computer models have been struggling more than usual in their longer-range forecasts for North America during recent days. In short, we can expect some big weather events over the next several weeks, but where and when they’ll unfold remains uncertain. “Perhaps this enormous tropical signal [the MJO] explains the angst-inducing and soul-crushing volatility of recent model runs,” tweeted Todd Crawford (The Weather Company) on Thursday.

Bob Henson co-wrote this post.