Tuesday, October 25, 2016

2016-2017 winter forecast for Duluth, Minnesota

/Issued October 25, 2016/

Weak La Nina expected this winter.
















Source http://www.weather.gov/
















Source http://www.weather.gov/dlh/

Note:  Left image is the temperature anomaly; Right image is the precipitation anomaly.
















Breaking down the last 11 weak La Nina winters at Duluth, Minnesota.

Average temperature and their departure from normal (Dec-Feb)

Dec-Feb average temperature:  13.3 degrees

1950-1951:  8.4 degrees (-4.9 degrees below average)
1954-1955:  13.2 degrees (-0.1 degree below average)
1955-1956:  10.6 degrees (-2.7 degrees below average)
1964-1965:  6.5 degrees (-6.8 degrees below average)
1967-1968:  11.6 degrees (-1.7 degrees below average)
1971-1972:  7.1 degrees (-6.2 degrees below average)
1974-1975:  13.7 degrees (+0.4 degrees above average)
1984-1985:  10.4 degrees (-2.9 degrees below average)
1995-1996:  8.7 degrees (-4.6 degrees below average)
2000-2001:  9.9 degrees (-3.4 degrees below average)
2011-2012:  21.1 degrees (+7.8 degrees above average)

Note:  Of the last 11 weak La Nina winters, 2 of them had above average temperatures, 1974-1975 and more recently in 2011-2012.

Snowfall totals and their departure from normal (Dec-Feb)

Dec-Feb snowfall average:  49.5"

1950-1951:  68.0" (+18.5" above normal)
1954-1955:  52.1" (+2.6" above normal)
1955-1956:  45.4" (-4.1" below normal)
1964-1965:  54.2" (+4.7" above normal)
1967-1968:  17.8" (-31.7" below normal)
1971-1972:  69.1" (+19.6" above normal)
1974-1975:  64.1" (+14.6" above normal)
1984-1985:  35.5" (-14.0" below normal)
1995-1996:  81.2" (+31.7" above normal)
2000-2001:  66.2" (+16.7" above normal)
2011-2012:  32.9" (-16.6" below normal)

Note:  Of the last 11 weak La Nina winters, there have been 4 that have had below average snowfall.

Before diving into what I'm expecting for this winter lets take a look back at the past few.

Note:  Meteorological winter runs from December 1st - February 28th.

Temperatures:

Note:  Average winter temperature 13.3 degrees
Base period:  1981-2010

2013-2014:  2nd coldest winter on record with an average temperature of 3.9 degrees; -9.5 degrees below average; The only winter that was colder than 2013-2014 was in 1874-1875 with an average temperature of 3.7 degrees.

2014-2015:  Average temperature was 13.1 degrees which was slightly below the average by -0.2 degrees.

2015-2016:  9th warmest winter on record with an average temperature of 18.8 degrees; +5.5 degrees above average.

*Number of subzero nights* (Low temperature below 0 F)

Note:  Average during the winter 34 nights
Base period:  1981-2010

2013-14:  65
2014-15:  37
2015-16:  19

Snowfall totals from the past few winters

Note:  Average winter snowfall (Dec-Feb)  49.5"
Base period:  1981-2010

2013-14:  78.8"; +29.3" above normal
2014-15:  23.4"; -26.1" below normal
2015-16:  49.8"; +0.3" above normal

Annual snowfall totals
Note:  Average is 86.1"

2013-14:  131.0"; +44.9" above normal
2014-15:  49.2"; -36.9" below normal
2015-16:  81.4"; -4.7" below normal

Here's my 2016-2017 winter forecast for Duluth, Minnesota

Temperatures:  Around -1.0 degree below average.  This winter should be quite a bit different than last winter.  For one, were not dealing with a strong El Nino this winter, instead a weak La Nina is forecast which typically results in below average temperatures and above average precipitation/snowfall in Duluth (See stats above)

Number of subzero nights:  30-35.

Dec-Feb Snowfall Total:  50-55" - Remember the average is 49.5"

Annual snowfall total:  85-90".  The annual average is 86.1"

Summary:  Cold temperatures should win out this winter.  Having said that, I still think will have a few thaws mixed in during the months of December, January and February, but I'm not expecting these thaws to stick around for very long.  The colder temperatures should have more staying power this winter compared to the warmer temperatures.

There should be frequent snowfalls this winter in Duluth, whether these are big storms or a number of light snowfall events remains to be seen but I think there is a decent chance that a few larger storm systems will come out of the northern Rockies and or the central Plains this winter.(The storm tracks will be crucial like they always are during the winter)

A few things to keep in mind:  Even though a weak La Nina is forecast this winter, this does not guarantee it will follow the trend of past La Nina events (Colder/snowier) The 2011-2012 La Nina resulted in a much warmer and much drier winter in Duluth.  So there's always that possibility for this winter to end up different than what is being forecast here in late October.

Note:  One thing I do follow is the Recurring Rossby Wave Train (RRWT) and the Organic Forecasting Method (Credit Josh Herman and others for the great work they do with this)  The long range forecast for this winter at Duluth per RRWT is for slightly warmer than normal temperatures by about 1.0 degree with ~45" of snow this winter which would be ~5" below average.  The annual snowfall total per RRWT is ~70" which would be ~16" below average.  It'll be interesting to see how this winter evolves.

In closing - I will be issuing long range monthly outlooks for December, January and February, see schedule below.

December 2016 outlook will be issued on November 30th.

January 2017 outlook will be issued on December 31st.

February 2017 outlook will be issued on January 31st.

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Reminder you can follow me on Twitter @dlhmnwx30 or friend me on Facebook timothy.burr1 Thanks for checking out my blog and feel free to share my winter forecast.

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Tim