Unusual West Arctic Storm Activity During Winter 2020: Another Collapse of the Beaufort High?

Abstract

AbstractWeather and sea ice forecasts provided in support of the U.S. Navy's Ice Exercise winter 2020 campaign in the Beaufort Sea noted frequent storms in the absence of the climatological Beaufort High which coincided with anomalous eastward drift of the region's ice cover. To place the 2020 Beaufort‐Chukchi regional atmospheric conditions in historical context, we evaluated winter low sea‐level pressure (SLP) extremes and storm characteristics in the region over the 1948–2020 period. March 2020 SLP in the Beaufort‐Chukchi region was the lowest of the modern reanalysis era (1009.07 hPa) with record counts of passing storms and days with SLP at least two standard deviations below the climatological mean. The Beaufort High collapse in winter 2020 continued a recent pattern of Beaufort High collapses dating back to 2010. Unlike other recent collapses, such as 2017, most of the late‐winter 2020 cyclones originated locally over the western Arctic Ocean.