The Role of January in the Character of Recent Winters in the United States

Abstract

The separate contribution of December, January and February temperature to the net seasonal anomaly for the 1975?76 through 1981?82 winter seasons is analyzed. It is found that the January departures contributed by far the most toward making these seven winter seasons well below average in much of the contiguous United States, particularly in the eastern half of the country. Each of these Januaries averaged from below to much-below the long-term average. By contrast, the Decembers and Februaries ranged from much-below to much-above the long-term mean. Intraseasonal relationships were explored to see what role monthly persistence may have played during these seven winters. It was found that although there was a general tendency for anomalies to persist in sign from one month to the next, particularly in the eastern third and the far West of the United States, the coldness of the Januaries appears to be the result of an intensified meridional circulation occurring for the most part, during the calendar month of January.