Groundhog Says: 6 More Weeks of Winter; Top-Five Snowstorm Belts Chicago, Detroit

A classic mid-winter snowstorm is sweeping across the nation, dumping heavy snow along a swath 2,000 miles long from Colorado to Maine. On Sunday the storm blasted Chicago with heavy snow and strong winds that created near-whiteout blizzard conditions, bringing the city its fifth heaviest snow on record--19.3". More than 18" of snow plastered Northwest Indiana and Southwest Michigan, with a storm-maximum snowfall amount of 20" observed in Kalamazoo, Michigan. Here in Southeast Michigan, my snow shoveling muscles are sore today after dealing with the 16.7" the storm dumped on Detroit--the city's third heaviest snowfall on record. By Monday morning, the storm had moved on to Ohio, hitting Cleveland with 4.7". The biggest totals during the remainder of the storm's trek are expected in snow-weary Massachusetts, with snow amounts near 12" expected in Boston. That city received 24.4" of snow from last week's blizzard; several locations in Central Massachusetts near Worcester received 36" of snow, and are expecting another 12" from this storm.


Figure 1. Westbound I-88 near IL Rte 53 in Lisle, Illinois on Sunday 2/1/15 @3:56pm CST. Image credit: Wunderphotographer Hammelmom.

Chicago's Five Biggest Snowstorms Since 1871:
1. 23.0 inches Jan 26-27, 1967
2. 21.6 inches Jan 1-3, 1999
3. 21.2 inches Jan 31-Feb 2, 2011
4. 20.3 inches Jan 12-14, 1979
5. 19.3 inches Jan. 31-Feb 2, 2015

Detroit's Five Biggest Snowstorms Since 1880:
1. 24.5 inches Apr 6, 1886
2. 19.3 inches Dec 1-2, 1974
3. 16.7 inches Feb 1-2, 2015
4. 16.1 inches, Mar 4-5, 1900
5. 14.0 inches, Feb 28-Mar 1, 1900

Groundhog Says: Six More Weeks of Winter!
In Punxsutawney, Pennsylvania, home of the world's most famous prognosticating rodent, Punxsutawney Phil, 3" of snow had fallen by Sunday evening, and on Monday morning the town was beset by a lovely wintry mix of snow, rain and freezing rain that only a hibernating groundhog could love. However, the skies cleared briefly at sunrise on Monday morning, allowing Punxsutawney Phil to see his shadow and make his usual fearless prognostication for the remainder of winter:

“Forecasts abound on the Internet,
But I, Punxsutawney Phil, am still your best bet,
Yes, A shadow I see, you can start to twitter,
Hashtag: Six More Weeks of Winter!”


Figure 2. Canada's famous albino groundhog named Wiarton Willy from the town of Wiarton, Ontario. Willie failed to see his shadow at dawn Monday, so his prediction calls for an early end to winter--in late February. In New York City, groundhog forecaster Staten Island Chuck also predicted an early end to winter. Image credit: wunderphotographer pincollector1.

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.

Grading Phil's forecasts
NOAA’s National Climatic Data Center (NCDC) analyzed Punxsutawney Phil’s forecasts over the past 27 years (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 concludes 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.”

What the pros say
The latest 16-day run of the GFS model shows the jet stream remaining farther south than usual over the eastern half of the U.S. during the coming two weeks, with our omnipresent "Ridiculously Resilient Ridge" of high pressure anchored over the Western U.S. This pattern will result in colder than average temperatures over the eastern half of the country, and warmer than average temperatures over the western half. The latest 1-month forecast from NOAA's Climate Prediction Center (CPC) shows this pattern dominating through February. The latest seasonal forecast from WSI.com agrees with this idea, but predicts that a warmer than average pattern may emerge over the Midwest and South during the last week of February, with below average temperatures confined to just the Northeast. Heading into March and April, WSI predicts warmer than average conditions across the northern tier of states, and cooler than average over the South (except for California, which will remain warm.) The latest 3-month forecasts for February - April from Columbia University's International Research Institute for Climate and Society and from CPC show the odds for cold weather easing over the Eastern U.S. during the period February - April, with near-equal chances of above or below-average temperatures. They forecast increased odds of cooler than average weather over Texas, with increased odds of warmer than average weather along the West Coast.


Figure 3. Temperature outlook for February 2015, as predicted by NOAA's Climate Prediction Center (CPC) on January 31, 2015. A continuation of the cool in the east, warm in the west pattern is favored.

Jeff Masters