Great Lakes Winter-Weather 700-hPa PNA Teleconnections

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  • 1 NOAA Great Lakes Environmental Research Laboratory, Ann Arbor, Michigan
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Abstract

A positive 700-hPa Pacific-North America (PNA) circulation index in December 1989 was replaced by a negative PNA index in January and February 1990. This circulation pattern reversal was associated with an anomaly reversal in air temperatures over the eastern half of the United States and anomaly reversals in the air temperature, snowfall, and ice cover of the Great Lakes. Evidence of PNA teleconnections with these Great Lakes climatic variables for a 20-winter base period is presented through correlations of anomalies in the monthly 700-hPa PNA index and PNA coordinates with anomalies in Great Lakes average monthly air temperature, snowfall, and ice cover.

Abstract

A positive 700-hPa Pacific-North America (PNA) circulation index in December 1989 was replaced by a negative PNA index in January and February 1990. This circulation pattern reversal was associated with an anomaly reversal in air temperatures over the eastern half of the United States and anomaly reversals in the air temperature, snowfall, and ice cover of the Great Lakes. Evidence of PNA teleconnections with these Great Lakes climatic variables for a 20-winter base period is presented through correlations of anomalies in the monthly 700-hPa PNA index and PNA coordinates with anomalies in Great Lakes average monthly air temperature, snowfall, and ice cover.

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