The End of Negatives?

Our last below zero reading was a -1 degree temperature that occurred around 2:30 AM on March 5.  The temperature was well above zero much of that night, but the sky cleared just after midnight, the temperature briefly dropped below zero, then the clouds moved back in and the temperature rose to nearly 10 degrees before most people headed to work or school.  In other words, that below zero reading was hardly even noticed.

Yet, that -1 degree reading did push the seasonal total for days with a low below zero to an even 70 days.  Those 70 days would rank the cold season of 2013-2014 as tied for the 14th highest such total on record.  Although, another negative morning is certainly possible, historically after this point they tend to only occur with a deep snow cover, which we currently lack.

Therefore, with any luck, our next negative morning in Fargo Moorhead will be near November 28, which is the average date of our first below zero reading of our next cold season.

Leap Day Troubles

Leap day.  It is what we call February 29, the day added onto February every fourth year to keep the seasons from slowly drifting through time as the earth takes slightly longer than 365 days to revolve around the Sun.  Leap day on occasion does impact climate statistics and this past winter was possibly one of those times.

Our recently completed winter was the 16th coldest on record, but the National Weather Service recently released a statement that this past winter was the 17th coldest on record.  The difference?  February 29, 1904.  Including that day makes the winter of 1903-1904 average temperature 4.4 degrees.  Without that day, the average temperature is 4.2 degrees.  The winter of 2013-2014 that we just completed had an average of 4.3 degrees meaning that depending on if you include that leap day this winter’s ranking changes by one position.   Is one statistic more accurate than the other?

Not necessarily, but leap day seems to get little respect, so I always include in all my analysis and most other researchers do as well.

Record Record

An email arrived in the weather center asking what day of the year has the largest temperature range from the record low to the record high.   The recorded low on January 8, 1887 was -48 degrees.  Thirteen years later, on January 8, 1900, the recorded high temperature reached 50 degrees.

That difference of 98 degrees still stands as the greatest range between a record high and low for any date in Fargo Moorhead.   In second place is March 18.  On March 18, 2012 the high reached 78 degrees with the record low for that date being -19 degrees observed in both 1883 and in 1923 for a difference of 97 degrees from record high to record low.   A snow free March as we learned in 2012 can be very mild, a snow covered March like last year and so far this year, can be bitterly cold.

Those snow variations in combination with a higher sun angle this time of year make March the month with most of the extreme record differences observed in this area.

Cold, Not Snowy

This past winter season was definitely cold, but it certainly was not snowy.  From December 1 through February 28, the official snow total from our cooperative observer in north Moorhead totaled 27.3 inches.  That is 2.1 inches below the average of 29.4 inches for that time period.  It was the second year in a row with snowfall being very close to the average during the three principal months of winter as last year 28.7 inches was recorded.

More important than the amount of snow is the water content in that snow.  The 27.3 inches of snow that fell in the past three months contained 2.09 inches of liquid, right at the average of 2.14 inches.  Meaning, this past winter was about as average as average gets for winter precipitation.  The driest of the three winter months was February as only 1.5 inches was measured last month, the 8th lowest total on record for that month.

That snow contained only 0.11 inches of liquid making February 2014 the 7th driest since records began in 1881.

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.

End of Winter

Yesterday was the last day of climatological winter.  It was a cold winter, the coldest since the winter of 1981-1982.  One of the most impressive stats these past three months has been the number of below zero days. From December 1 to February 28 the daily low temperature was below zero on 65 days which is nearly three out of four days over the past three months.

As of this morning this cold season is currently ranked as having the 19th highest number of days below zero since records began in 1881 (with more negative days to come).  Yet, if you only include the three principal months of winter, the 65 days recorded last season would rank as the 6th highest.  Plus, if you exclude the 1880s before temperature measurement standards were initiated in 1891, this past climatological winter would rank 3rd behind the winters 1935-1936 and 1949-1950 both tied with 66 negative days.

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.

Others are Worse

It has certainly been a cold winter; yet, in Fargo Moorhead no specific cold records have been set.  Elsewhere around the United States it has also been cold with more notable cold weather statistics.  Toledo, Ohio for example, dropped to -15 degrees this past Wednesday morning for the second time this winter, in 140 years of records, this was the first time that the city hit -15 in two different months.

The Twin Cities, even with a significant urban heat island around the airport, has dropped below zero 44 times this winter, only four away from breaking into the Top 10.  In Fargo Moorhead, we need 17 more days to break into the Top 10.   Chicago has already recorded enough days to reach the Top 10 for most below zero days in that city.  Snow locally has been uneventful, but Detroit, Michigan has already recorded enough snow to rank in their Top 10, plus the city recorded their snowiest January on record.

Yes, our winter has been tough, but other locations have by their standards fared even worse.

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.