Abstract
The hemispheric distributions of all significant 5-day mean High and Low centers at 700 mb. observed twice weekly during the years 1947–58 are presented by months and latitudes and also for the entire 12-yr. period. Average seasonal circulations and their relative vorticities for the same period, as well as zonal geostrophic winds, are shown for comparison. Although the relative vorticity patterns of the long-period circulation resemble the patterns of occurrence of 5-day circulation centers, there are some centers which are not easily related to features of the circulation on such a long time scale as 12 years.