Groundhog Says: Early Spring! Plus: a Groundhog Day Tornado Outbreak?

In Punxsutawney, Pennsylvania, home of the world's most famous prognosticating rodent, Punxsutawney Phil, gloomy clouds prevailed at sunrise on Tuesday morning, preventing Punxsutawney Phil from seeing his shadow. His fearless prognostication for the remainder of winter, as presented as his official groundhog.org web site, looks like this, then:

“Hear Ye, Hear Ye, Hear Ye
Now, this Second Day of February, Two Thousand and Sixteen, the One Hundred and Thirtieth Annual Trek of the Punxsutawney Groundhog Club….
Punxsutawney Phil, the Seer of Seers, Prognosticator of All Prognosticators, was awakened from his borrow to the cheers of his thousands of faithful followers….
In Groundhogese, he directed the President and the Inner Circle to the precise prediction Scroll, which translated reads:


The inner circle goes to great ends
 
To keep me abreast of latest trends

Down in my burrow I never get bored
   
Riding on my hover board

And I sure have fun flying my drone
 
But weather forecasting is my comfort zone

Is this current warm weather more than a trend?
   
Per chance this winter has come to an end?

There is no shadow to be cast,
   
An early Spring is my forecast!"



Figure 1. Canada's famous albino groundhog named Wiarton Willy from the town of Wiarton, Ontario. Willie saw his shadow at dawn Tuesday, 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, and predicted an early end to winter. Image credit: wunderphotographer pincollector1.

Grading Phil's forecasts
Phil saw his shadow in 2015, predicting six more weeks of winter. While February ended up colder than average over the contiguous U.S. in 2015, March was much warmer than average (the 12th warmest March since 1895), making it difficult to grade Phil's forecast as being successful or a flop. NOAA’s National Centers for Environmental Information (NCEI) analyzed Punxsutawney Phil’s forecasts between 1988 - 2015 (thanks to Doyle Rice of USA Today for pointing this out.) If we evaluate just the twelve 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 seven blown forecasts. NOAA concluded in last year's version of this analysis that “It really isn't a 'bright' idea to take a measure such as a groundhog's shadow and use it as a predictive meteorological tool for the entire United States.”

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 2016, as predicted by NOAA's Climate Prediction Center (CPC) on January 31, 2016. A continuation of the warm in the north and west, and cool in the south pattern is favored.

What the pros say
The latest 10-day runs of the GFS model and the European model show an outbreak of Arctic air pushing through the Midwest beginning on Monday next week, and bringing much below-average temperatures to large portion of the eastern half of the country during the second week of February. As discussed by Bob Henson in his Monday blog post, this plunge of cold is expected to happen as a consequence of a split of the polar vortex caused by a Sudden Stratospheric Warming (SSW) event. However, NOAA’s experimental 3-4 week temperature forecast for Feb. 13-26 shows no strong indication for either above- or below-normal temperatures east of the Great Plains, so next week's cold blast may be just a one-week affair. The latest seasonal forecast from The Weather Company's Business Solutions group (formerly known as WSI.com) agrees with this idea. Heading into March and April, they predict a classic El Niño pattern of relative warmth across the northern states and cooler than average temperatures across the southern tier of states, with March being more consistently colder than average than February. The latest 3-month forecast 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 warmth in the north and coolness in the south. Wunderblogger Steve Gregory has a more detailed analysis of the long-range forecast for February in his Monday afternoon post, Major Snow storm - Severe T-Storms and Pattern Change.


Figure 3. Outlook for severe weather on Tuesday, issued at 10:29 am EST Tuesday, February 2, 2016, by the NOAA Storm Prediction Center.

Not in the groundhog's forecast: Tornado outbreak possible Tuesday PM
A springlike severe weather setup is taking shape for Tuesday afternoon between the Mississippi River and the Appalachians. Gulf moisture is already in place, with dew point temperatures already into the 60s as far north as western Tennessee. Mild, unstable air will continue flowing from the Gulf behind a warm front now lifting northward through Kentucky, while a sharp cold front and upper-level energy approach from the west. NOAA's Storm Prediction Center is calling for an enhanced risk of severe weather from Mississippi and Alabama into western Tennessee and Kentucky. As of late Tuesday morning, the areas at greatest threat for discrete supercell storms later Tuesday---perhaps even strong tornadoes--are near the warm/cold front intersection zone, over western TN and KY, and across central and southern MS and AL, especially later in the evening. A weaker round of severe weather is possible Wednesday east of the Appalachians, from the Gulf Coast to the Delmarva.

Jeff Masters and Bob Henson


Video 1. Smart groundhogs use WU to improve their prognostications!