Winter Warmth or Winter Worries?

With fall color beginning to appear on trees around the region and the longer periods of darkness, it’s time to start thinking about winter. Are we in for a relatively mild winter or will we have a frosty forecast? As always, it depends on who you ask.

Let’s start with the Climate Prediction Center (CPC). The CPC is the division of the National Oceanic and Atmospheric Administration (NOAA) responsible for long-range forecasting. According to the CPC information page, much of their analysis is based on El Nino and La Nina conditions in the tropical Pacific and the effects of these conditions on sensible weather over the United States.

According to the CPC, the Upper Midwest will have high probability of having above normal temperatures during Meteorological Winter, which lasts from the first day of December to the last day in February. The CPC also is forecasting an equal chance of above or below normal precipitation during this period. These probabilities are calculated using 30 year climate averages, along with an analysis of El Nino and La Nina conditions and their effects on the region during this 30-year period.

Closer to home, La Crosse and surrounding communities also are forecast to have a high probability of above normal temperatures during Meteorological Winter. According to the Three Category Temperature Outlook: Dec-Jan-Feb 2009_10, we currently have a 49% chance for Above Normal temperatures, a 31% chance for Near Normal temperatures, and a 20% chance for Below Normal temperatures during this period. Above Normal temperatures are defined as average temperatures warmer than 20.8 degrees Fahrenheit; Near Normal temperatures are defined as average temperatures between 16.9 and 20.8 degrees Fahrenheit; and Below Normal temperatures are defined as average temperatures lower than 16.9 degrees Fahrenheit.

Another winter forecast also has received wide attention recently. This is the forecast from the Old Farmer’s Almanac. According to the Almanac’s Annual Weather Summary: November 2009 to October 2010, “Winter [in the Upper Midwest] will be much colder than normal . . . Precipitation and snowfall will be below normal in the east and above normal in the west.”

The forecasts made by the Almanac are based on a secret formula developed by Robert B. Thomas, the founder of the Almanac, in 1792. While the formula is a secret, the Almanac does state that their forecasts are based on solar science (including the study of sunspots and solar activity), climatology (based on the same 30-year climatological averages used by the CPC), and meteorology.

As the Almanac states on its Web site, “We predict weather trends and events by comparing solar patterns and historical weather conditions with current solar activity.” Using these methods, the Almanac claims an accuracy of 80%.

So who will be right? Obviously, we’ll know for sure on March 1, the start of Meteorological Spring. El Nino conditions have developed in the Pacific Ocean, and are expected to continue into 2010. An El Nino winter is usually — but not always! — a bit warmer than a non-El Nino winter in the Upper Midwest, and the data for the past 30 years seem to support the National Weather Service outlooks.

As noted by meteorologists in La Crosse, “. . . it is worth considering the potential for the cold forecast, at least for part of the winter. The above normal cold season forecast by CPC is quite reasonable, overall, but . . . it’s worth noting that past history in these types of situations have produced some rather cold periods during the winter” [NWS emphasis].