Staying Above Minus 40

Thursday, January 8, is the anniversary of the coldest temperature ever officially recorded by the National Weather Service for Fargo Moorhead.  On this morning in 1887, a temperature of 48 below was recorded by what was then called the U.S. Weather Bureau which was located at the Moorhead Post Office and Federal Building at 521 Main Avenue at what is now the Rourke Art Museum.  This number does not reflect wind chill.  It was a mercury-in-glass thermometer reading.  A similar temperature of 47 below was recorded February 9 of 1888.  There are just over a handful of readings in the minus 40s in the entire Fargo Moorhead record book; all of them in a six year period between 1883 and 1888 (Temperature records began in 1881.).  Although 39 below has been reached on two occasions since, most recently on February 1, 1996, it has not been 40 below in Fargo Moorhead since the 1880s.  At least, not officially.     Meteorologist John Wheeler

Winter 2013-2014 Statistics

The National Climatic Data Center (NCDC) released their analysis of the winter of 2013-2014 last week.  NCDC ranked the period from December 1 through February 28 as the 25th coldest on record for North Dakota.  You may recall locally it was the 16th coldest on record, but western North Dakota was not as cold making the average for the entire state lower in the cold rankings.

Minnesota on the other hand recorded a more evenly spread cold winter throughout that state.  Taken as a whole, NCDC ranked this past winter as the 6th coldest on record in Minnesota.   The past 119 winters are used in these rankings.  Nationally, NCDC ranked the past winter as the 34th coldest on record.

Using other datasets and analysis puts that ranking closer to the Top 10, but no matter what the ranking; most Americans east of the Rocky Mountains experienced a winter that will not soon be forgotten.

Heat Island No Match

There were many impressive statistics from this past winter.  There are two in particular that caught my attention and these were both Chicago and the Twin Cities recording a Top 10 coldest winter on record.  Chicago recorded an average temperature of 18.8 degrees from December 1 through February 28.

That ranked as the 3rd coldest winter on record for that city with records going back to 1872.  The Twin Cities average temperature was 9.7 degrees and that ranked as the 9th coldest on record with records used to 1891.  The location of where the official temperatures and precipitation has been taken has moved through the years in both cities, but the one consistent fact through time has been the expansion of the urban heat island influence in these large metropolitan areas.  The temperature can be several degrees warmer within these cities than it is in nearby rural areas.

Yet even with that man-made heat influence these cities recorded such a cold winter.  Just imagine what the average temperature would have been in a similar winter 100 years ago.

March Cold Record

By now many of you may have heard that both Fargo Moorhead and Grand Forks set a record on Saturday, March 1 for the coldest high temperature not only for that date, but also for the month of March.  The high in Grand Forks (UND/National Weather Service site) was -9 degrees and in Fargo Moorhead the high reached -8 degrees.

Of note, the high of -8 degrees in Fargo occurred just after midnight with the afternoon high reaching only -10 degrees.  Both of those highs shattered the daily record for lowest maximum for March 1 and narrowly set new monthly records.  The previous coldest March high was -7 in Fargo Moorhead set back on March 10, 1948 and in Grand Forks the previous record was -8 set on March 6, 1955.

Other cities in the region that set new March records for lowest maximum over the weekend included Sioux City and Waterloo, IA, Omaha and Lincoln, NE, and Eau Claire, WI, plus many others around the country.

The Winter of 2013-2014

The average temperature this past winter (December through February) was 4.3 degrees.  That ranks as the 16th coldest winter of the 133 winters on record in Fargo Moorhead (records began on January 1, 1881, therefore the first winter has incomplete data, meaning the first winter of record was the winter of 1881-1882).

The last colder winter in Fargo Moorhead was back in 1981-1982 when the average temperature was 3.3 degrees.  Other fairly recent colder winters were in the late 1970s.  The winter of 1978-1979 the average temperature was 0.6 degrees and the winter of 1977-1978 the average was 2.8 degrees.  Those were the two coldest back to back winters since the 1880s.  Even with such a cold winter being recorded, no record lows were set.  Of interest, the coldest temperature of winter was just -25 degrees on January 2 which is 3 degrees above the average coldest temperature recorded in a year locally.

There have been colder winters, but if you are under 30, it was the coldest winter in your lifetime.

The Negative Winter

Yesterday in this space I mentioned that the low temperature at Hector Int’l recorded a low below zero on 65 of the 90 days during our just completed winter season.  On most of those days, the air temperature remained below zero for many hours of the day and on some days; the temperature remained below zero the entire 24 hours of that day.

Using the hourly reports from the airport, the temperature in Fargo was below zero for approximately 900 hours December 1 to February 28.  That many hours would total 37 complete days of the 90 days of meteorological winter. Put another way, approximately 40% of winter was below zero.  Grand Forks’ total hours represented in days would be about 45 days below zero, the Twin Cities, 20 days and Bismarck 25 days.

It may not have been even close to the coldest winter on record, but it was still a very memorable one.

Cold Without Records

It has been a very cold winter, yet, not only have no record lows been set, we have not even come close.  February will be ending quite cold but the odds of Fargo Moorhead recording a record low this week does not look likely.  Although we are rapidly approaching March, the record lows are still near -30 degrees.

Back on February 20, 2008 the temperature at Hector Int’l dropped to -31 degrees which did set a record for that date and we would likely need a reading that low to break any records with our current cold snap.  One factor that will hinder the temperature from breaking any records is our current snow pack.  Although deep, it is crusty and hard and not as conducive to strong radiational cooling as fresh more powdery snow.  In other words, hard crusty snow will help keep the temperature up this week, meaning, although it will likely be a very cold finish to February, had we recorded some fresh snow cover recently we would be even colder.

Top 30 For Now

One of the most asked questions lately has been how does this winter rank in comparison to past winters.  Snow wise, this winter has been quite ordinary, but of course when this question comes up, it is almost always referenced for temperatures.  Through Monday, February 10, the average temperature since December 1 was 3.5 degrees.  That would rank that period as the 23rd coldest on record.

As a comparison, it would be similar to the average temperature for the same period during the winters of 2008-2009, 1996-1997 and 1995-1996.  The biggest difference would be all those winters had significantly more snowfall to this point.  Based on the warmer temperatures that have moved into the area and are expected to remain for at least the next week (most days), that ranking will slowly drop.  When climatological winter ends on February 28, we may not even finish in the Top 30, yet, no matter the ranking, this is clearly a noticeably colder than average winter.

A Stronger Sun

The lack of snow in the past couple of weeks have made for excellent travel conditions on the main roads, but many city streets and parking lots remain ice covered.  That will likely be changing soon and not necessarily for the reason you may think. The one obvious reason that the secondary roads will be improving soon would be the rise in air temperatures, but there is another more subtle reason, the Sun.

As the Sun angle slowly increases, you will notice even on days with an air temperature well below freezing, that melting will take place on area roads on a sunny day.  Although the stronger Sun will help with clearing the roads and parking lots from the abundance of ice, it also tends to cause problems.  The melting that occurs will freeze nearly every night meaning slick spots each night.

That melt and freeze cycle also creates something that will be very common in the coming weeks, potholes.

50 and Counting

Today is the 50th day with a low temperature below zero this season.  The long-term average is 48 such days, so we have already surpassed that milestone with at a good month of potential negative lows ahead of us.

Perhaps even more noticeable is the fact that on 12 of those days, the high temperature also failed to get to 0 degrees.  The long-term average for below zero high temperatures is 10 such days.  Two of the days with a high below zero, the high was in the double digits below zero with the coldest being a high of -14 on December 31.  We average two days per winter with a high of -10 degrees or colder.  Considering it will become increasingly more difficult to remain that cold as our days continue to get longer, the odds are pretty high we will not record another -10 degree or lower high this winter.

But another single digit negative high is definitely a possibility.