THE JANUARY WARM SPELL AND ASSOCIATED LARGE-SCALE CIRCULATION CHANGES

Abstract

Recurrent departures of mean weekly temperatures from a smooth seasonal trend during the past several decades in the northeastern United States are shown to be a manifestation of a shift in the planetary circulation. The geographical extent of these temperature excursions from normal and the synoptic pattern through which they occur are discussed. Secular changes in the amplitude of the warm spell which occurs in January over the northeastern United States are directly related to simultaneous changes in the planetary circulation and are not independent fluctuations.