Monday, November 9, 2015

Recent Snowfall

Frequent light snowfall over the past 12 days has brought the snow depth up to 6 inches in Fairbanks, which while still modest, is actually above the long-term normal of 5" for this date.  A more substantial snowpack is in place now in the hills; for example, the Keystone Ridge COOP (1600' elevation) is reporting 16" on the ground, which is the most for this date since 2004.  The SNOTEL sites to the northeast of Fairbanks are reporting between 11" and 20", as seen in the map below (click to enlarge and view the small icons).

Farther afield, McGrath also has 6" (normal 4") and Bettles has 14" (normal 9").


The onset of relatively snowy weather in the interior is not too surprising in view of the highly positive phase of the North Pacific Mode.  The NPM index in October was the second highest on record since 1900, and according to station data since 1950, a positive NPM phase tends to bring above-normal precipitation to interior Alaska.  The map below shows the percentage of years with above-normal precipitation in October through December when the October NPM index was strongly positive.  More details on the NPM influence can be found in the slideshow from my UAF talk back in September:

 https://accap.uaf.edu/sites/default/files/The_BLOB_AK_Weather.pdf


[Update November 10: another 2.3" of snow yesterday brings the snow depth to 7" in Fairbanks as of midnight.  This is now the snowiest start to November since 1990, and 4th snowiest on record.  The season-to-date snowfall of 33.5" is the 3rd highest on record.]

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5 comments:

  1. NL7YNovember 9, 2015 at 7:09 PM

    Richard if I may add here's an audio file of the presentation that makes for an excellent fill on the analysis.

    https://accap.uaf.edu/sites/default/files/N_Pacific_SST%20_Blob_%20AK_Winter_Climate_edited.mp4

    One version of Hartmann's 2015 NPM paper. There may be other sources:

    http://www.atmos.washington.edu/~dennis/Hartmann_NPM_2015.pdf

    And finally Francis' 2012 paper discussing the Arctic Amplification and climate anomalies from another perspective:

    http://marine.rutgers.edu/~francis/pres/Francis_Vavrus_2012GL051000_pub.pdf

    Gary

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    1. Richard JamesNovember 10, 2015 at 9:45 AM

      Yes indeed, Gary, the audio may be helpful.

      I noted that the season-to-date snowfall of 33.5" is the 3rd highest on record through this date, and is not usually reached until January 11 on average.

      Next up on the agenda: some much colder weather.

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    2. NL7YNovember 10, 2015 at 10:47 PM

      Arctic Village has a history of cold. It might be worth an analysis versus other Interior Alaskan locations.

      It's beautiful country with good people.

      Gary

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    3. Richard JamesNovember 12, 2015 at 1:10 PM

      Gary, I like the idea but unfortunately historical data is very sparse for Arctic Village; there is not even a 1981-2010 normal in the NOAA database. The closest station with more complete data (although not so much of late) is Chandalar Lake; perhaps I'll take a closer look at their climate history.

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    4. NL7YNovember 12, 2015 at 6:04 PM

      Thanks for looking Richard. I did the same and yes several years of observations are absent in the few sources I found. Probably a function of lack of $, power to run self-contained obs units or just an absence of one, and a lack of observers reporting to formal agencies.

      They likely have a connection to air carriers prior to schedule
      flights.

      It's a vast area (NE Alaska) that appears devoid of much in the way of weather reports. I had hoped there would be a source.

      Not sure of the correlation of Chandalar Lake to Arctic Village. It's somewhat separated to the west but in the same major river drainage. Maybe they do share similar weather when both report (?).

      Gary

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