Cold or Warm Winter?

The lower 48 states have for the most part recorded a mild winter.  Locally, the month of December finished 11.2 degrees above average and the month of January is currently running about 10 degrees above normal.  If February records temperatures this mild, the winter of 2011-2012 will challenge the winters of 1986-1987 and 1930-1931 as the warmest winter on record.

Yet, as we enjoy one of our warmest winters since 1881 in the Red River Valley, other parts of the world have not been so lucky.  As a general rule, if one part of the Northern Hemisphere is well above average, you will almost always find another area that is recording the opposite extreme.  For example, on January 17, parts of the northern Sahara Desert received an unusual snow event of several inches.

Plus, much of India has experienced a very cold winter with temperatures averaging 10 to 15 degrees below normal, with Bangalore recording their coldest January on record to date.  The cold Indian winter has created much hardship for millions of people.

That Bridge has Passed

I have been asked numerous times in the past week if I thought Fargo Moorhead would break the record for the least snowiest winter on record.   When I mention that we have already passed that mark, there always seems to be a sigh of disappointment from the person who asked.  Plus, when I mention we may not even end up in the Top 20 least snowiest winters on record, the disappointment seems to change to a surprise.

Recent winters have tended to skew our perception as to how frequent in the past so called brown winters occurred.  Our current snow total is approximately 1 foot, already more than the winter of 1957-1958 when only 9.3 inches was measured.   The winter of 1911-12 recorded 23.9 inches and is currently ranked as the 20th least snowiest winter.

Therefore with 3 months left in our potential snow season, we need to record less than 12 more inches to even finish in the bottom 20.  The last time we accomplished that was during the winter of 1986-1987.

Far from Zero

Snow is like the star quarterback or running back on a football team.  It gets all the publicity and to a large degree for good reason.  Snow gathers our attention; it needs to be shoveled and plowed.  It creates hazardous travel conditions and often disrupts our schedule.

But the long 50 yard pass for a touchdown that makes the highlight reel would not be possible if your offensive line did not do their job.  In the same way, although everyone notices the snow, the moisture content of the snow is something that largely goes unnoticed.  Yet in the end, it is the most important element of a snowfall.  Although until the event on Sunday this winter has been mainly brown, precipitation amounts have been far from zero.

The three principle months of winter average 2.14 inches of liquid precipitation (rain and melted snow) and since December 1, officially, Fargo Moorhead has recorded 0.87 inches of precipitation, certainly below average, but not by as much as most people would probably guess.

Air Mass

The term air mass is used frequently by meteorologists.  By definition an air mass is a large volume of air that has similar properties.  Those properties would include temperature and often moisture content.  These air masses will develop certain characteristics over the course of many days or weeks by remaining in a certain geographic regions.

In the winter, the far northern latitudes receive little or no sunlight allowing the air in these areas to become increasingly cold.  Plus, because the nearby moisture source, theArctic Ocean, is frozen over, the air also becomes very dry.  Although the term Arctic is frequently used when colder air moves in, most of our colder air masses locally originate in centralCanadaand not in areas above theArctic Circle.

Therefore, by definition many of our cold snaps in the winter should be referred to as a polar air mass, notArctic.  Although, the air mass the moved through a couple of days ago was of true Arctic origins originating in Siberia and interiorAlaska.

Always Humbling

Yesterday in this space, I mentioned that our just completed first half of winter was the warmest such stretch since 1881.  As the old saying goes, records are made to be broken, plus, as I wrote about earlier in the week, the winter of 1877-1878 may have started even warmer, so the term record is a relative term with a database of only 130 years.

Yet, the past several weeks was still impressive to me in the sense that these exceptionally mild temperatures occurred during a time-frame when many atmospheric and oceanic signals suggested that temperatures would be colder, or at least nearer to the long-term average.  Again, our database of past events is limited, especially when it comes to oceanic conditions which have the largest overall impact on our weather, yet glancing through the data, I could not find a winter that started off well above average with similar overall conditions to what is currently present in the oceans and in several atmospheric oscillations currently in play.

Simply put, this winter is a prime example of our limited skill in forecasting beyond 1 or 2 weeks.

Warm Half

January 15 marked the half-way point of climatological winter and that stretch we just finished was the warmest on record.  The period from December 1 through January 15 averaged 25.3 degrees which was not only the warmest such period on record; it was the warmest by over 3 degrees.

The previous record for the first-half of winter was back in 2006-2007 with an average temperature of 21.8 degrees.  The second half of that winter finished much colder, yet, that winter overall still finished above average.  As many of you will recall, after that winter, the next 4 all finished with below average temperatures.  The first half of the winter of 2008-2009 finished with an average temperature of just 2.8 degrees which was the 13th coldest such period and a remarkable departure from what we have recorded this year.  The past month and a half was not only warm, but relatively dry.

Since December 1 Fargo Moorhead has officially recorded 0.53 inches of rain and melted snow which was the driest start of winter in 10 years.

Positive Winter

The average number of days with a low temperature below zero during the winter in Fargo is 50.  So far this season, below zero temperature readings have been rare.  Officially we have recorded three days with below zero temperatures.  The first was back on December 9, then the other two occurred last Thursday and Friday, with the below zero reading on Thursday occurring late in the day.

I have referenced the winter of 2006-2007 a few times recently as that was the last winter that recorded a mild December and early January.  That winter we also had very few below zero readings through early January, just like this year, but in the end, 29 such days were recorded as the second half of that winter turned much colder.  So although it is likely this winter will have far viewer negative days than the average, at this point I do not think that the record for the fewest number of negative days in a winter is in jeopardy.

That record is 14 set back in the winter of 1986-1987.

Warmer in the Past

Although the winter has turned noticeably colder in the past few days, the temperatures this winter have been so mild that on many occasions I have heard numerous people mention that this has been the nicest winter ever.  As frequent readers to this blog know, the weather records in Fargo Moorhead started in 1881. It is unfortunate that records did not start a few years earlier, because the winter of 1877-1878 was likely either the warmest winter, or one of the warmest winters since European settlement in the region. 

Bismarck’s weather records started in 1874 and that winter ranks as the 2nd warmest behind the winter of 1930-1931.  That winter is considered the warmest on record for the Twin Cities, although, it was before the modern record cut off of 1891 for what is considered official records for them.  The February 10, 1878 edition of the St. Paul Pioneer Press had a story reporting that the cavalrymen from Bismarck, Dakota Territory left the city in shirtsleeves.

Too often we think of our weather as being unique, when it actually has all happened before. 

What a Stretch

The first 10 days of January was a remarkable stretch of mild temperatures.  The average temperature during that period was 29.7 degrees, which was 5 degrees warmer than any other such stretch on record and a phenomenal 20.3 degrees above average.   Locally during that period we recorded 4 record highs, one tie and on two other days that we missed the record by 2 degrees or less.

Three of those record highs were in the 50s, including a 55 degree high on January 5 which was the warmest temperature recorded in January since 1881.  The last time Fargo Moorhead recorded three 50 degree or warmer high temperatures this month was back in 1942.  The most 50 degree high temperatures in January was back in 1900 when 4 such days occurred.

Back in December 2006 we had a brown Christmas, that was followed by a very warm first half of January, just like this year, but the 2nd half of the winter turned very cold.  A reminder on how quickly patterns can switch in this area