Associations Between Anomalies of Temperature and Precipitation in the United States and Western Northern Hemisphere 700 mb Height Profiles

Abstract

The relationship between anomalous seasonal surface temperature and precipitation in the contiguous United States and concomitant fluctuations of western Northern Hemisphere 700 mb height as a function of latitude are examined. Findings are consistent with other studies dealing with the spatial patterns of midtropospheric teleconnections and their surface manifestations. A strong inverse relationship between temperature in the eastern United States and heights in the western Northern Hemisphere polar regions is present during winter and spring, especially in winter. In summer the association is positive and is most evident in the southern tier of states. Fewer significant correlations are found between seasonal precipitation and midtropospheric height, with the strongest ones occurring in winter and summer. It is shown that in winter, during the period 1948–81. the frequency of below-average 700 mb heights has increased in the temperate latitudes of the western Northern Hemisphere. At the same time, a general increase in above normal polar latitude heights has taken place. This in turn has been associated with lower winter temperatures in the eastern United States. Some suggestions are offered as to the physical-synoptic mechanisms underlying these relationships, although this report is mainly of a fact finding nature. Several data tables and charts are presented for purposes of application to climate studies and long range forecasting.