Tuesday, December 7, 2021

How to Eliminate Cold

The reprieve won't last long, but a very powerful Bering Sea storm has dramatically swept away the cold air that dominated the state in the past few weeks.  It was an extraordinary transformation: check out the sequence of daily temperature maps below, showing Friday through yesterday.

Rick Thoman notes the extraordinarily rapid change in the statewide daily temperature index:

The storm was a nasty one along the Bering Sea coast, with very high winds.  Here are some of the peak gusts, courtesy of NWS:

The following article describes some of the impacts on coastal communities.  Rick notes that sea ice was sufficient to prevent serious coastal flooding, which illustrates a major upside of the recent cold weather.


Here's the NWS sea ice analysis from Friday.

Below are the 500mb and surface analysis maps from 3 am yesterday morning (December 6), courtesy of Environment Canada.  MSLP of 958 mb was reported on Sunday afternoon on St. Lawrence Island (at both Gambell and Savoonga), and that appears to be close to the all-time record for the area (about 955 mb according to 1950-present ERA5 data).

This powerful storm may come as a bit of a surprise in a strong La Niña, because just a few weeks ago I discussed the fact that the Aleutian Low tends to be weaker during La Niña.  However, another very interesting aspect of La Niña winters is that daily variability tends to be higher, so the weather patterns near Alaska tend to be more volatile.  I explored this topic a few times in past years, so search for "ENSO variance" if you're interested; or check out the following post.

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