Blocking in the Western Hemisphere, which had

• Main Authors: Cold In The United States, Raymond A. Green
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1969
• Subjects: Bering Sea; Canada; Greenland; Pacific; Aleutian Islands
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.395.2324; http://docs.lib.noaa.gov/rescue/mwr/097/mwr-097-03-0281.pdf

decreased in November, came back strongly in December. The most anomalous blocking feature of the December circulation was the strong ridge over the Aleutian Islands (fig. 1) which replaced the deep Bering Sea Low of November (Stark, 1969)’. resulting in anomalous 700-mb height changes between months of more than 200 m. Meanwhile, the mid-Pacific trough of November moved eastward and intensified at lower latitudes, the ridge in the Rockies decreased, and the mid-United States trough broadened eastward into the Atlantic. Blocking also increased in Canada and persisted over Greenland and Scandinavia, resulting in a band of positive height anomalies from the western Pacific across Canada to northern Russia (fig. 2). South of the positive zone, height departures were negative from the eastern Pacific