Continental vs Maritime

The temperature this month in Fargo Moorhead has ranged from eleven below zero to 75 degrees for a range of 86 degrees in a month.  It’s hard to dress for that.  Fargo Moorhead is a perfect example of a continental climate in which the temperature can vary as air is blown around the region by various random weather patterns.  The greatest one-day range was 44 degrees on March 14 when it was 24 in the morning and 68 in the afternoon.  In contrast to this, the temperature this month in Key West, Florida, has ranged from 69 degrees to 84 degrees for a range of 15 degrees.  The greatest one-day range was 13 degrees from a low of 69 to a high of 82.  Key West weather is maritime.  The temperature of the surrounding ocean dominates the weather, keeping daily as well as day-to-day changes minimal.  Meteorologist John Wheeler

Drought and Heat

The official thermometer for downtown Los Angeles has already recorded four days in the 90s this month.  This is a record for so early in the season.  As California starts its fourth summer of drought conditions, the expectation is there will be a lot of hot days which, in Los Angeles, will mean many summer days in the 100s.  There is a very close relationship between drought and record heat.  Here in Fargo Moorhead, 29 of the 92 summer daily record highs (June 1 through August 31) were set in the 1930s which is by far the driest decade on record here. The connection is simple.  When the soil is dry, it is heated up more efficiently by sunlight, which makes the air hotter.  Summer droughts create dry soil and usually have lots of sunny days. Since 1993, the Red River Valley has been quite rainier than the long-term average, and so summer record highs have been rare in recent years.   Meteorologist John Wheeler

Late Season Snow Likely

After an early spring, threats of snow have rematerialized in our forecasts on a routine basis.  Late-season snows are typical enough that even April carries a monthly snowfall average of three inches.  Last year, Fargo Moorhead got a 2.3 inch snow on March 31 and a 1.5 inch snowfall on April 16.  Two years ago, we got buried by 9.1 inches on April 15-16 followed by another 3.2 inches on April 17-18.  Late season snows usually melt quickly but often provide more shock value than the snowstorms that happen in the middle of winter.  My own interest in meteorology as a lifetime profession was probably triggered by a now famous spring snowstorm that covered southern Wisconsin (and me) in 12-18 inches of snow April 7-8 or 1973.  My family had just moved to the Midwest from Alabama the previous summer and that April snowstorm was my first blizzard.     Meteorologist John Wheeler

Going to Extremes

March 23 is an interesting day in the Fargo Moorhead weather record book.  With records dating to 1881, there are two versions of this particular date which stand out.  In 1910, it was 80 degrees.  This remains the only 80 degree day in March in the history of Fargo Moorhead.  The spring of 1910 was extraordinarily warm and dry and with the drought lasting well into summer, it was a year of many crop failures.  From the opposite end of things, March 23 of 1974 remains the latest day in the year on record with a subzero high temperature.  That was one of those years in which spring seemed to never show. And following a week of cold days and a fresh two inch snowfall on March 22, the 23rd delivered a low of eleven below zero and a high of one below. These are two extreme illustrations of how variable the weather can be in March.   Meteorologist John Wheeler

First Day of Nothing

Friday, March 20, is the Vernal Equinox.  Many people call this the first day of spring without thinking much about it.  Can spring start at the same moment everywhere on Earth?  Think about the equatorial regions.  At the equator, March and September are when the sun is directly overhead at noon.  It is hot all year at the equator.  But it is often hottest in March and September.  The weather is also rainiest and most humid along the equator around the time of the equinoxes because the direct sunlight causes peaks in evaporation rates to go along with the peaks in temperature.  Around the time of the Solstices in winter and summer, the middle of the world has its two slightly less hot seasons.  So there are relationships between the equinoxes and weather, but they are general and varied around the world.  The Vernal Equinox is really an astronomical moment with no immediate impacts on the weather anywhere.  This makes the “first day of spring” a fairly useless concept.    Meteorologist John Wheeler

Tornado Absence

 

March is typically one of the peak months for tornadoes in the United States.  Though rare so early in our region, it is common for there to be big outbreaks in March across the Southern Plains or the Southeast.  This year, for just the second time since 1950, there were no tornadoes reported across the country from March 1-15.  The other year was 1969. The cause for this year’s absence of twisters is, of course, the jet stream pattern, which has kept the Great Plains extremely dry this month so far.  And although the Southeast has been rainy, the rains have been general soakers.  The pattern just has not favored the development of tornado-producing supercell thunderstorms.  This should not be taken as a sign that our warm season will be free of tornadoes.  Meteorologist John Wheeler

Drought Brings Good With Bad

Since 1993, the weather pattern over the Red River Valley region has been wet.  Dry periods within this time frame have been few and generally brief. Average annual rainfall increased 15-20 per cent starting in 1993.  The weather has been wetter and for a longer period than the dust bowl years were dry.  Eventually this pattern will end but it is not possible to know in advance if the change will take place in another hundred years or if is starting right now.  Weather is difficult that way.  Although drought is hard on our overall economy and water shortages can make life more difficult, drought is a naturally occurring part of nature.  It has a way of rebooting wetlands, leaving them healthier and more productive.  A drought would lower the almost annual flood threat by lowering reservoir levels.  And a drought would lower Devils Lake.   Meteorologist John Wheeler

March Blizzards

 

It is a myth that there are always huge blizzards in March.  In the distant past as well as in recent years, March and April pass without any blizzards at all.  Of course, it is also true that some of our most severe blizzards in history have happened in March.  Across North Dakota, the benchmark for blizzards may well be the monster blizzard of March 3-6, 1966, when one to three feet of snow with winds 50 to 100 mph built drifts 30 feet high.  But March is not the only month with a tendency to produce memorable winter storms.  All of the cold months from October through April have produced at least a few severe blizzards.  Interestingly, the big ones are most common in three of the months; November, January, and March.  November and March provide the greatest proximity of warm and cold as the seasons change.  January is the king month for hybrid Alberta Clipper storms connecting with super strong Arctic high pressure systems.   John Wheeler

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Average is Average

 

Average March snowfall is 9.1 inches.  Average April snowfall is 3.0 inches. This does not mean we are for sure in for a foot of snow before spring.  Nor does this mean we should expect around a foot of snow unless something goes wrong with the weather.  What is average implies nothing about what is supposed to happen.  Average is derived by taking an average.  Almost all of the time, weather is above or below average and the average is just the middle of all the samples.  We usually use the average of the three most recent complete decades to calculate the average.  At present, we are using 1981-2010 to compute our averages.  Each new decade the averages change.  This is so what we refer to as average keeps up with the gradual changes in our climate without overreacting to sudden swings in year-to-year weather.  We might get very little snow during March and April.  Or the storm track could change and we might get a lot.  That’s weather.  That’s all.    John Wheeler

 

Here Comes the False Spring

The limited snow cover this winter is a big reason for the warm up coming the next few days.  The milder weather is primarily a result of upper level winds and not the lack of snow, but it is the lack of snow which will likely cause several of the next few days to be anywhere from five to fifteen degrees warmer than they would have been had there still been significant snow on the ground.  Although the sun’s rays feel warm on our faces, sunlight does not heat the air very much at all.  The sun is mainly able to warm the atmosphere indirectly, by heating the ground with radiation (They’re not called sun rays for nothing.), which then heats the air through convection.  When the ground is white with snow, most solar radiation is reflected, so the air remains much colder.  The melting of the snow may give us an early spring, but it may well be a false one.  Weather history suggests a return to a snow-covered landscape is likely before spring comes to stay.     Meteorologist John Wheeler