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The frequency and intensity of Great Lake cyclones

TitleThe frequency and intensity of Great Lake cyclones
Publication TypeManual Entry
Year of Publication1998
AuthorsAngel, J. R., and S. A. Isard
Journal of Climate

Cyclones are an important feature of the Great Lakes region that can have important impacts on shipping, lake temperature profiles, ice cover, and shoreline property damages. The objective of this research is to analyze the frequency and intensity of cyclones that traversed the Great Lakes region, the changes of these characteristics since 1900, the interrelationship of cyclone frequency and intensity, and their relationships to circulation patterns and regional temperature and precipitation. Significant increases in the number of strong (less than or equal to 992 mb) cyclones over the twentieth century were found for the annual, cold season, November, and December time periods. In contrast, the frequency of all cyclones in the annual and warm season time series and the central pressure of all cyclones in the annual, cold, and warm season time series displayed significant decreases from 1900 to 1939. Relationships between cyclone frequency and intensity and between cyclone and anticyclone frequency and intensity suggest that there is a partial compensation within the region. As the number of cyclones increases, their intensity decreases, As the number of cyclones increases, so does the number of anticyclones. And, finally, as the cyclones become stronger, so do the anticyclones. Comparisons with the Pacific-North American teleconnection index indicate that lower (higher) cyclone frequency is associated with more zonal (meridional) how. Comparisons of cyclone characteristics with temperature and precipitation in the Great Lakes region shows that cyclone frequency is inversely related to temperature and directly related to precipitation in most month and season categories. In contrast, the relationships between cyclone intensity and climate variables are inconsistent.

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Community Notes

Study Findings:

  • the frequency of strong cyclones over the Great Lakes (GL) from 1900-1990 increases in November and remains high through April
  • most summer cyclones are weak
  • annual and cold season cyclone frequency increased over the 90 year period
  • cold season cyclone frequency is correlated with zonal midtropospheric flow above North America rather than meridional flow
  • cyclone frequency is directly related to average GL precipitation amounts and has statistically significant correlations for September through April (excluding December)
  • strong cyclones have statistically significant correlations with precipitation for September, October, November, January, February, and March.