Sunday, January 18, 2015

Warmest Winter To Date

The mean temperature in Fairbanks since November 1 has now moved into first place in the historical rankings since 1930; in other words, if we define winter as November-March, then this is now the warmest winter on record through January 17.  The winter-to-date temperature now exceeds that of 2002-2003 by the slimmest of margins.

The chart below shows the evolution of the winter-to-date mean temperature this year in red, compared to 2002-3 in blue and the historical range in gray.  This winter has been steadily climbing through the rankings as warmth at the surface has become increasingly anomalous.  We can see that mean daily temperatures close to +10 °F would be required to maintain first position for the remainder of winter; this would be more than 15 °F above normal for late January, so it will be a challenge to hold onto the record in the near-term.  In fact, we're very likely to fall back out of first place in the coming days, as January 2003 had a very warm spell around the 20th.


[Update: Brian coincidentally made a similar graphic, and his analysis shows that the winter of 1928-29 was warmer through January 17.  This is helpful context for the current warmth.  It's a matter of personal preference as to whether to include pre-1930 data in this kind of analysis - I usually don't do so, because the Weather Bureau/NWS era began in December 1929 and I have greater confidence in the quality of the Fairbanks data since then.  Rick Thoman went so far as to say that pre-1930 data from Fairbanks are "plagued by data quality issues", although this may apply more to pre-1920 data.  My own (relatively uninformed) opinion is that there's very useful information to be gleaned from the early years, but the data should be used with caution.]

6 comments:

  1. Clouds, no wind, warm. We deserve one of these every decade.

    Gary

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    1. The no wind comment applies to the valley floor in Fairbanks. In areas away from town, especially with some elevation, the vegetation is generally frost free. At valley level the hoar frost and snow still cling. The temperature Inversion has formed its protective bubble at the surface.

      And as usual for midwinter the Tanana Jet to the south and advective drainage through the Chena River basin in town have yet to disturb the frost. That will change as we progress into February, and particularly when the winds of March develop with increasing solar insolation.

      It could be -50F right now. Every day it isn't takes us closer to Spring.

      Gary

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  2. I added an update to point out Brian's analysis, showing that winter 1928-29 was warmer in Fairbanks through January 17. I typically exclude pre-1930 data for reasons stated.

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    1. I typically use 1920 as the cutoff for temperatures and 1915 for precipitation when looking at seasonal trends. Individual readings before 1930 should be viewed as suspect. However, they are still part of the climate record so its impossible to ignore them completely. It's a difficult decision to make and there is no right answer.

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  3. In Juneau this means we've had to close our beloved ski area, none of our usual snow, and we're being drowned in rain and flood warnings. Death by precipitation. Most miserable winter ever.

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  4. No question about it, Lisa: truly miserable. My co-author Brian noted that Juneau has now had its wettest January on record.

    https://www.facebook.com/AlaskaClimateFacts

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