Groundhog: Six more weeks of winter!

Punxsutawney Pennsylvania's famous prognosticating rodent, Punxsutawney Phil, saw his shadow this morning. According to tradition, this means that a solid six more weeks of winter can be expected across the U.S. From the official web site of the Punxsutawney Groundhog Club, groundhog.org:

Here Ye! Here Ye! Here Ye!

On Gobbler's Knob on this fabulous Groundhog Day, February 2nd, 2009
Punxsutawney Phil, the Seer of Seers, Prognosticator of all Prognosticators,
Awoke to the call of President Bill Cooper
And greeted his handlers, Ben Hughes and John Griffiths

After casting a joyful eye toward thousands of his faithful followers,
Phil proclaimed that his beloved Pittsburgh Steelers were World Champions one more time

And a bright sky above me
Showed my shadow beside me.

Six more weeks of winter it will be.


How did this this crazy tradition start?
It all started in Europe, centuries ago, when February 2 was a holiday called Candlemas. 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.

What the models say
The latest 16-day run of the GFS model shows the jet stream retreating to a position in southern Canada in about a week, which will usher in milder temperatures over the eastern half of the U.S. compared to average. However, the model predicts that a series of cold air outbreaks typical for February will occasionally dip down over northern regions of the U.S. over the coming two weeks, bringing colder than average temperatures to the Pacific Northwest, and near average temperatures to the Midwest and Northeast. The latest 1-month and 3-month outlooks from NOAA's Climate Prediction Center show a continuation of this pattern for the remainder of winter and into Spring, with a heightened chance of above-average temperatures in the Southern U.S. Cooler than average temperatures in the Northern Plains are typical when weak La Niña conditions are present in the Eastern Pacific (Figure 1), as is currently the case.


Figure 1. Departure of winter temperature from average for winters when a weak La Niña event was present. Temperatures in the Northern Plains have typically been 1-2°F below average for the eight winters in the past 50 years that have had weak La Niña events. Image credit: Jan Null, Golden Gate Weather, and NOAA/ESRL.

Kentucky's ice storm
Six more weeks of winter is not what ice storm-battered Kentucky needs, as the state continues to recover from its most widespread power outage in history. High temperatures Tuesday and Wednesday will be below freezing over the most of the state, but should warm into the 50s by the end of the week. More than half of the 600,000 customers affected by the outage have now had their power restored. The previous largest power outage in state history occurred just five months ago, when the remnants of Hurricane Ike brought wind gusts near hurricane force to Kentucky.

The Groundhog Oscillation: convincing evidence of climate change
According to a 2001 article published in the prestigious Annals of Improbable Research titled, "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.

More on climate change in my next post on Tuesday or Wednesday, when I'll look at claims that the Earth has been cooling since 1998.

Jeff Masters