Wednesday, July 24, 2019

Northwest Warmth

Blog posts will be scarce in the next week or two as I'm traveling, but here's a quick post to highlight the really extraordinary warmth that northwestern Alaska has seen in recent weeks and months.  In large part owing to the lack of nearby sea ice (in winter) and much above-normal nearby ocean temperatures (in summer), air temperatures have been almost constantly above normal for nearly two years now.  According to data from Kotzebue, the last calendar month that was cooler than the 1981-2010 normal was August 2017.  Click to enlarge the figure below.

But as if the events of 2017-2018 were not enough, the warmth has kicked it up another notch since the middle of last winter, as each of the last 6 months has been at least 10°F warmer than normal.  Remarkably, Kotzebue hasn't seen a single day below normal since March 18, and that was only by a fraction of a degree; the last "significant" cold spell was in the first half of January.  Daily temperatures have been frequently more than 1 standard deviation above the daily normal, and it is becoming unusual to see a day that is not in that upper 15% of the climatological distribution (above +1SD).

Here's one more statistic to illustrate how warm it's been this summer so far: Kotzebue has seen 16 days this year with a daily minimum temperature at or above 60°F.  That's easily a record for any year, and it's more than occurred in total in the 3 decades from 1940 to 1970.  They even managed a daily minimum of 69°F on July 9 this year, which is an all-time record high value and more typical of the tropics than the Arctic.

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