The Winter of 2014-2015

The winter of 2014-2015 started on December 1, 2014 and ended on February 28, 2015.  Average air temperatures over that period ranged from 7° to 22° in North Dakota via data from the North Dakota Agricultural Weather Network (NDAWN).

Winter Temp
Average Temperature from December 1, 2014 to February 28, 2015

That would place much of the state reasonably close to the current 30-year average winter temperature.  The coldest anomalies were in Walsh County where the winter of 2014-2015 finished slightly below the mean and the warmest anomalies were in scattered in western North Dakota and in southern Steele and northwestern Cass County where the winter finish around 4 degrees above average.

Winter Anomaly
Winter of 2014-2015 Temperature Anomalies

 

According to statistics compiled by the National Climatic Data Center (NCDC) the average temperature anomaly for North Dakota taken as a whole was +0.8°.

Although November was quite cold with much of North Dakota recording temperatures between 5 and 10 degrees below average, there was a rapid shift in the upper-air pattern after the first week of December.

November Temperature Anomalies
November Temperature Anomalies

That cold November was followed by a nearly equally above average December.  Persistent cloud cover made for some very mild mornings in December with numerous records set for maximum minimums across the state.

December 2014 Temperature Anomalies
December 2014 Temperature Anomalies

 

The mild trend from December lingered into January.  The cloud cover plus other variables made for much of the warmth of December, but in January the above average temperatures will more associated with a more zonal (west to east) flow of the jetstream and/or the core of the Jet was in south Canada allowing for mild Pacific air to make frequent intrusions into North Dakota.

map

The departure from average for the month of January ranged from +2 to +9 degrees.  Warmest anomalies were in Steele and northwestern Cass County.  The coolest anomalies were in Walsh County.  The difference generally dealt with snow cover during the month.

After a mild December and January, the cold of November returned the region in February.   Negative anomalies from average during the month of February ranged from 6 to 12 degrees with the exception of the southwestern corner of North Dakota.  That part of the state had minimal snow cover plus tended to be in the warm sector of several precipitation events.  The combination of those two factors lead to the warmer temperatures, albeit, still below average.

 

February 2014 Temperature Anomalies
February 2014 Temperature Anomalies

 

The winter of 2014-2015 may have finished near the 30-year average for temperature, but most the state finished well below average for precipitation.   Winter is a dry season for North Dakota with average precipitation only between about 1.2 to 2.2 inches during the three principal months of winter, December, January and February.   With the statewide average closer to the bottom figure at 1.42 inches.  Therefore, with the winter average being 1.07 inches according to analysis done by the National Climatic Data Center (NCDC), precipitation averaged between about 0.50 to 1.00 inches below average.    Which is of course, just a single rain event in the summer time.

Winter 2014 - 2015 Precipitation for North Dakota.
Winter 2014 – 2015 Precipitation for North Dakota.

 

Taken as a percent of normal, most of North Dakota, not surprisingly, ranked in the 50 to 75 percent of normal range.  A few exceptions with precipitation in central North Dakota as well as a few location averaging above normal for winter precipitation.  In a dry climate often times just a single precipitation event can mean the difference between above and below normal rain and or snowfall.

 

Percent of Normal Precipitation
Percent of Normal Precipitation

 

Because there were some rain events during the winter, the amount of precipitation does not necessarily reflect the amount of snowfall this past winter.  Below are the snow totals for December, January and February.

 

12 Dec 2014
December 2014 Snow Totals

 

 

 

January 2015 Snow Totals
January 2015 Snow Totals

 

 

 

February 2015 Snow Totals
February 2015 Snow Totals

 

There are always exceptions when you make broad categorical statements, but much of the state averaged only between 15 and 25 inches of snow so far during the current snow season meaning a 15 to 30 inch snow deficit from the current 30 year totals through mid March.  This past winter was the lowest snow total year in many locations since the Winter of 2005-2006 and 2001-2002.  That is for the three principal months of winter, not seasonal snow totals.  Usually, seasonal snow totals, as our snow season runs from September through May, means that some relatively snow free December through February periods have recorded significant snow in November, March or April for example.  If we use the snow season approach, then through mid March, you would have to go back to the early 1980s to find such limited snow totals to this point.

Historic Fargo Snowdepth
Historic Fargo Moorhead Snowdepth

 

In summary, the winter of 2014-2015 finished near or slightly above the current 30-year average for temperatures, with precipitation ending up noticeably below average across a high percentage of the state.

Daryl Ritchison