Old Farmer's Almanac and NOAA Issue Contrasting Predictions for Winter 2010

(Sept. 8) -- Like a pair of formidable cloud banks colliding, two marquee weather predictors are brewing up a storm of contention with their contrasting winter forecasts.

According to the 2011 edition of "The Old Farmer's Almanac," which bills itself as "North America's oldest continuously published periodical," this coming winter will see a period of "global cooling" in which most of the nation will see colder-than-normal temperatures, The Associated Press reported.

The National Oceanic and Atmospheric Administration, which was formed in 1870 has reached a different conclusion, however. NOAA is forecasting a warmer winter overall for most of the United States, with the biggest temperature increases coming in the Southeast, but colder weather befalling the Northwest.

NOAA also points out that as of mid-August, 2010 has been shaping up to be the earth's warmest year in recorded history. In addition, the agency finds El Nino growing stronger.

What accounts for the differing prognostications? Surge Desk breaks it down:

How does the Old Farmer's Almanac make its long term weather predictions?
It's classified! Janice Stillman, the editor in chief of the Old Farmer's Almanac, recently described the publication's methodology by saying that while a host of methods were used, a key component in the mix was a "secret formula." What is known about how the Old Famer's Almanac makes its predictions is that it includes analyses of planetary positioning, ocean tides and sun spot activity.

How does NOAA make its long term weather predictions?
NOAA discounts the indicators considered by the Old Farmer's Almanac, calling them scientifically dubious. Nor does the agency rely on any secret formulas. In large part, NOAA's long term weather predictions are based on the fluctuation of El Nino or La Nina weather patterns in the Pacific Ocean. In addition, NOAA tracks long term data trends, as well as oscillations in 30-60 day weather patterns, computer forecast modeling, and other means to help determine odds of above-or-below-normal temperatures.

Who has been more accurate in predicting weather, NOAA or the Old Farmer's Almanac?
On its website, the Old Farmer's almanac boasts that its forecasts are "traditionally 80 percent accurate." The National Weather Service makes no such specific claims, and takes pains to offer caveats on the process of making long-term predictions, such as the following:

In general, long range forecasts for temperature are usually more accurate than these for precipitation. This is because temperature varies only by small increments from place to place; it is more constant. On the other hand, precipitation is widely variable through time and from place to place. Even in short term forecasts out to 48 hours, precipitation forecasts are written as a probability of occurring. Therefore, it would seem more difficult to extend a precipitation forecast out to several months.

The accuracy of any outlook varies both regionally and seasonally. For example, coastal areas experience a more stabilized climate throughout the year, making it less changeable and easier to predict.