Leap Day Alteration

Recently we broke the record for the most days above freezing in a winter season.  Fargo Moorhead has recorded 46 such days since December 1.   The old record was 44 set back in the winter of 1923-1924.  That final 44th day with a high above freezing occurred on February 29, as 1924 was a leap year, that extra winter day helped keep that year as the number one season in that category until this year.

Although most leap days do not have a major impact on a winter season statistics, this year may be an exception.  Tomorrow is the last day of climatological winter, so all statistics for this season ends tomorrow.  The extra snow and moisture tomorrow could be sufficient enough to have a noticeable impact on how this past winter ends up with regard to average precipitation.  Currently the winter season is running about one-half inch below normal on precipitation and nine inches below on snowfall.

After tomorrow those deficits may largely disappear.

Black Swan?

Winter forecasts are always made referencing the three coldest months of the year, December through February.  Although March is definitely a winter month in our climate, this week brings to a close what turned out to be an exceptional warm and somewhat dry winter in theUnited States.  The winter weather was so opposite of what many had forecasted that phrases like a “rogue winter”, or a “black swan event” have been used to describe the season.

Those terms would suggest that this winter has been out of the norm or unique.  Frequent readers of the column will likely not be surprised by me acknowledging that I am not fond of such comments.  We have had similar winters in the past and will likely in the future.  Just because something is unexpected or extreme should never be taken as if there is something wrong with the weather.

Instead, each season or weather event instead, should be a learning tool, as there is still much about our atmosphere that we do not understand.

Think Winter

Our mild winter with minimal snow to this point has prompted several people to ask if this means we will see an early spring.  Looking back at similar winters to this one brings a mixed bag of weather.  Some years continued the mild trend into spring, other years turned colder.

My general response every February to those asking about an early warm up is if you expect it to get warm in March, you are likely going to be disappointed.  One of our warmestMarcheson record occurred in 2010.  Granted the last three days of the month the high was in the 60s, but most of the rest of that month the high was in the 30s and 40s, not very spring like by most definitions.  Our average high does not even reach 32 degrees until March 8 and we have to wait until April 6 for our average high to reach 50 degrees.

Therefore, if you go into March expecting more winter, more often than not, you will not be disappointed.

Afghanistan Cold

The harsh winter weather that has hit much of Europe and Asia has also been impacting Afghanistan.  This in turn has created another battle for our troops stationed there, fighting the cold and the snow. Kabul, the capital, has picked up between 30 and 40 inches of snow this winter, which may not sound like much, but that is the most snow recorded there in at least 15 years.

Plus, Kabul is situation in a valley and the mountains around the city have picked up much heavier snow that have occasionally blocked access to other parts of the country.  Although the American troops are well supplied for such conditions, many of the local citizens are very poor and have struggled to stay warm.  Although the combination of the snow and bitterly cold temperatures has brought much hardship, there is some good news on the horizon.

The abundant moisture from the melting snow will be a welcome sight in a country that has suffered from a decade long drought.

Weather Change

The winter of 2001-2002 was very mild.  That winter finished with an average temperature of 20.0 degrees and is currently ranked as the 4th warmest on record.  That winter like this winter also had an abundance of days with temperatures above freezing.  In total, that winter recorded 38 days with a high over 32 degrees.  In many ways, that winter is a good reference to what is occurring this year.

In no way should this be considered a forecast, as each year is different, but that cold season was an example of how quickly the weather patterns can change.  After 3 months of exceptionally mild conditions, March 2002 turned cold and snowy.  The average temperature that month was colder than what was recorded in both December and February that season, with only January finishing colder.

Looking through the records I could find no other cold season when a March was the 2nd coldest month of winter.  The odds favor that not happening this year, but you should never say never in our climate

Twitter

Although I try to post blog material as often as I can, if you are interested in following the day to day happenings of our weather, I would recommend you follow me on twitter.  You will find me @darylritchison

I post on twitter frequently with some interesting tidbits on a daily basis as well as my forecast.

Pattern or Snow?

The average temperature for the three principal months of winter, December through February, is 12.6 degrees.  With nearly two weeks left in climatological winter, our current average is near 23 degrees or about 10 degrees above normal.  I have had numerous people ask me if this winter has been mild because of the lack of snow, or has it just been because of a mild weather pattern.

Snow cover, especially a deep snow pack, has a noticeable impact on the air temperature.  The amount of influence varies on the age of the snow and cloud cover but as a general rule, a deep snow pack will lower temperatures by at least 5 to 10 degrees (or more).  Therefore, you could assume that our mild winter has been attributed to the lack of snow, yet, our dominating upper level wind flow has been from the west this winter, bringing in mild Pacific air to our area most of the time.

Therefore, our mild cold season can be attributed to both the lack of snow and a mild weather pattern.

Higher Sun

Although this winter has been so mild and snow free that our roads have generally been bare and dry most of the time, during most winters that is not the case.  Because of that, I have always looked forward to Valentine’s Day as the time of year when road conditions would start to improve.  Fargo Moorhead is located near 47 degrees north latitude where the sun angle from November through January is generally too low to help melt the ice off area roads unless the temperatures are well into the 20s.

But today at solar noon, the Sun will be 30 degrees above the horizon for the first time since October 27.  From my observations, once the sun angle reaches 30 degrees or higher, snow and ice tend to melt off pavement, especially asphalt, even when temperatures are as cold as 0 degrees.

So although icy roads have been infrequent this winter, the next time we do see some snow we can count on the Sun as well as road crews to get those roads ice free

Snowy Eurasia

It would likely surprise no one to learn that the percentage of the lower 48 states with snow on the ground is well below average.  Overall the North American continent is running roughly one million square kilometers below the long-term mean, with most of that anomaly occurring in the United States.  Yet, overall, the Northern Hemisphere has an above average snow pack.

If the western hemisphere is running well below average, that means that Europe and Asia must be reporting snow in places that usually would be snow free, and that has definitely been the case in recent weeks.  Many areas in southern Europe are reporting widespread snow cover this month.  Parts of northern Africa as well as the Middle East also have snow on the ground.

Whereas North America is running well below average, Europe and Asia combined have a snow cover of approximately 1.5 million square kilometers above average for this time of year.