392 MONTHLY WEATHER REVlEW DECEMBEB 1953 THE WEATHER AND CIRCULATION OF DECEMBER 1953' A Month of Fast Westerly Flow

• Main Author: Jay S. Winston
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Canada; Greenland; Gulf of Alaska; Pacific; Iceland; Alaska
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.394.8337; http://docs.lib.noaa.gov/rescue/mwr/081/mwr-081-12-0392.pdf

700-mb. chart with height contours and departures from normal (both labeled in tens of feet) for November %-December 28,1953. Below-normal heights Prevailed north of latitude 50 ' N. while positive anomalies were dominant in the subtropics1 ridges from eastern Asia eastward to the central Atlantic. Thus a nearly steady-state circulation over virtually the fig. 3B). Many cyclones formed east of the mountains in entire hemisphere accompanied the sustained high index Alberta, triggered by perturbations moving in from the of the last month and a half of 1953. Pacific, while some Pacific storms actually moved across the mountains. Several of these storms were deep as RELATED CYCLONE TRACKS, FRONTS, AND they moved through western Canada with central pres-PRECIPITATION sures often below 1000 mb. Monthly mean sea level Fast westerly flow had a decided effect on the tracks of pressures averaged 7 mb. below normal over northern cyclones in the North American region during December. Alberta and also significantly below normal along the The outstanding storm track, along which storminess storm track from the Aleutians to southeastern Canada was extremely frequent, extended from the Gulf of Alaska and near the Iceland-Greenland region (Chart XI inset). eastward across southern Canada and thence north- Hence a clear channel of low pressure along the line of