July is King

July is climatologically the warmest month of the year.  The average temperature this month is 71 degrees which is nearly five degrees warmer than the average for June and nearly two degrees warmer than the average for August.  The average temperature for June is 66.2 degrees and the average temperature in August is 69.3 degrees.  Although this month averages the warmest temperature of the year, that does not necessarily mean it is always the warmest month in every year.

Since 1881, July has been the warmest month, just 70 percent of the time.  August has ranked as the warmest month 26 percent of the time, or but in other words, in about one year in four.  On rare occasions, June has ranked as the warm month, but that has only occurred five times in the record book with 1994 being the last year that occurred.  Acute weather observers may have thought June 1995 would have ranked as the warmest month that year as it was a very warm month and still ranks as the 3rd warmest on record, but August 1995 was slightly warmer.

July has been the warmest month in each of the past eight years, one of the longest stretches on record, so we are over due for August to best July for warmest month of the year.

Triple Digit Drought

The extreme heat recorded to our south this week prompted the question as to when was the last 100 degree high in Fargo Moorhead. On July 30, 2006 the high reached 102 degrees and that still stands as the last 100 degree day locally.

Earlier that month, on July 15, 2006 the high was 101 degrees which was the first triple digit high since June 17, 1995, a stretch of 11 years.  Before that day in 1995, six years had passed since the previous 100 degree day was recorded during the hot and dry summers of the late 1980s.  Therefore, since 1989 the official high at Hector Int’l has reached 100 degrees only three times. There is no other such period since 1881 with so few days with extreme heat.

The abundance of moisture and the associated clouds and wetter soils have been partially responsible for this lack of heat in recent years, but the other reality is, the atmosphere has rarely been conducive for temperatures that warm in the past two decades.

Record Cold Season

There are many ways to analyze climate data.  The most familiar is based on the calendar year, January through December.  Hydrologists make use of what they refer to as the water year, which runs in most areas from October through September.  If we want to admit it or not, we live in a cold dominated climate and therefore, using the cold season to represent variations in climate often highlights differences between years better as frequently, it is the five coldest months of November through March that set different years apart.

The cold season stats run from July 1 through June 30, these dates already mark the time frame for official snow tallies.  This means Saturday will mark the end of the 2011-2012 cold season and these past 12 months will go down as the warmest such period on record besting 1986-1987 by a remarkable 1.6 degrees.  Before this year, the difference between the two warmest cold seasons was only 0.2 degrees and the two coldest years were separated by 0.9 degrees, making these past 12 months unique in the record book.

One Year Ago, The Minot Flood

I wrote this article about one year ago.  I am reposted it as the one year anniversary of this devastating event is upon us.

—————————————

Just three years ago, the thought that western North Dakota would be experiencing historic floods in the near future would have been seen as unrealistic considering how dry that area was as seen with the Palmer Indexes in June 2008.

Back in the summers from 2005 through 2008, moisture was in short supply, the rivers were barely running, Lake Sakakawea in 2005 was running at historic lows and rain was desperately needed.  Much of this past decade the western one-third of North Dakota experienced frequent dry spells, whereas, the eastern part of North Dakota and western Minnesota was generally experiencing very moist conditions.

By the summer of 2009, enough rain had fallen in western North Dakota that the drought was over and the transition to over saturation was starting to become more evident in some parts of central North Dakota.  This excessive moisture was from a combination of winter snow and abundant rainfall that occurred during the spring of 2009.

Unknown at that time, but the Minot flood had its roots in 2009.  But the main branches of the flood came in 2010 when the word drought seemed like a distant memory as the rains came turning the semi-arid high plains into a vast wetland.  The rivers went from dry to flowing fast, the low areas were once again filled with water and the dry days were a memory.  Instead, seeping basements, sump pumps running frequently became the norm in areas that were missed by the wetness that plagued eastern North Dakota and western Minnesota since the early 1990s.

The wet summer of 2010 was followed by a wet autumn, that was followed by a snowy winter.  Then another season of saturation occurred in the spring of 2011.  The spring of 2011 was the 7th consecutive season with above average precipitation for the state of North Dakota.  In eastern Montana it was the wettest spring on record.

The extremely wet winter in combination with one of the wettest springs since 1893 lead to a massive surge of moisture down the Missouri River.  The Missouri River flooding,  although certainly made worse by spring rains,  was mostly caused by the tremendous snow that fell during the winter of 2010-2011.  The abundant moisture in recent years has cause Lake Sakakawea to rise 49 feet since 2005.  That 49 foot rise would be enough water to cover the state of North Dakota to a depth of 4″.  That is just one small example as to how much water this area has received in recent years.

The excessive snow from the winter was not only an Rocky Mountain event, but it was also very snowy over much of the northern Great Plains.  I’m sure few of us have forgotten that Fargo Moorhead recorded the 3rd snowiest winter on record.   The prairie provinces of Canada also observed abundant snow fall this pass winter, that was followed with continuous spring rains.  Some parts of Saskatchewan likely had their wettest first six months of a year since at least 1900.

Below is a graphic for the precipitation anomalies from average (rain and melted snow) that has fallen over the northern part of the United States.  That area in eastern Montana with nearly 20″ of rain above normal does extend,  from reports,  into Saskatchewan, the source region of the Souris River that flows through Minot.  That part of the United States and Canada only averages between 12″ and 18″ of rain per year and many areas received that much in just the past two months.

Therefore, it should surprised no one that the entire northern tier of the high plains of the United States was completely saturated by the end of May 2011.  Although this Palmer Index chart below is only for the United States, the prairie provinces of Canada would be listed as extremely moist as well.

The excessive moisture found its way into all the river systems.  In Minot,  the Souris has been flowing high since early April, with the river at or above flood stage for most of the last three months.

Although the Souris was running very high, it was manageable for the city of Minot until mid June.  In fact, after a mandatory evacuation of parts of the city, the residents were allowed back in and many thought the flood fight of 2011 was over, yet, only days later, parts of the city were evacuated again and then the battle was quickly lost as the river surged to record levels.

What changed?  More rain.  With all the up stream reservoirs near or at capacity, a major rain event hit Saskatchewan with another 4-7″ of rain.  Doppler estimates of that event can be seen below:

Because of the distance from the dopplers in the United States, the estimates above do not fully describe the areal extent of the heavy rain in Canada.  This was the last straw that finally broke the proverbial “camel’s back”.  With so much water flowing into the reservoirs that were already at capacity, the dam operators had no choice but to have outputs equal inputs.  This cause the flows into the Souris River to increase from around 11,000 cubic feet per second to near 30,000 cubic feet per second rushing toward the city of Minot.   This in turn raised the Souris to record breaking levels flooding hundreds of homes and businesses.

Some floods happen in a day, but wide scaled flooding as what occurred along a huge stretch of the Missouri, the Souris and other river systems, usually have their roots in a long slow process.  Hints to the devastation in Minot came nearly two years ago with the rapid saturation of the soils and the corresponding high river flows for the past two years.

The Red River Valley has been wet for two decades now, our hints are already evident.  A major precipitation event could bring devastation to any part of the Red River drainage system.  We have seen this in the Devils Lake Basin and in Grand Forks in 1997.  Will we see it somewhere else?  Hopefully not, but if it does happen, we sadly shouldn’t be surprised.

 

The Summer Solstice

Today marks the summer solstice in the Northern Hemisphere.  At 6:09 PM CDT the Sun’s direct rays will be located over the Tropic of Cancer which is approximately at 23.5 degrees north latitude.  If you were standing at that point at solar noon (which is rarely 12:00 PM) you would not cast a shadow as the Sun would be directly overhead.

The only location in the United States where you could observe this phenomenon during the year would be in Hawaii as all the main islands are south of 23.5 degrees.  Key West, Florida comes close, but that location is at approximately 24.5 degrees north, so although you would cast only a tiny shadow, the Sun would be at 89 degrees above the horizon today, not quite the 90 degrees necessary to be directly overhead at solar noon.

In Fargo Moorhead, the Sun will reach 66.5 degrees above the horizon today, the highest of the year and this is in stark contrast to the Winter Solstice in December, when the Sun will peak at only 19.5 degrees.

As strange as it may sound, on my bucket list is to be in a location where the sun is directly overhead someday at solar noon and have a picture taken.  Someday.

Cherry Picking

The 1960s and 1970s were generally cold decades in the United States and around the world.  This came after a few decades with general warming.  That time frame, especially in the 1970s, was a period when there were articles and publications concerned over the cooling earth.  Since then, most locations on the planet have once again warmed slightly.

Last week, Climate Central, a political advocacy group sent out a news release stating that Minnesota and numerous other states have recorded rapidly warming temperatures since 1970.  Cherry picking is a concept of selecting the highest or lowest point in a data set to inflate your claims.  Recently there have also been claims of the earth cooling rapidly since 1998, a very warm year globally.  Both claims could be considered correct, but both use specific data points that do not represent the true nature of the temperature data.

As the old saying goes, there are lies, damned lies and statistics.  In other words, there are a lot of agendas out there, so buyer beware.

 

Positive Feedback

One of the reasons often given for the persistence of above average precipitation over the past two decades was that wet begets wet.  In other words, the wet soils allowed for more evaporation, which in turn caused it to rain more and that cycle continued year after year.

This is referred to as a positive feedback loop where a change in one variable, soil moisture, reinforces the original process, rainfall.  Although there is some truth to this, it is or was a minor player.  An example would be the summer of 2011.  It was a very wet summer until August 6, but then the rain stopped and never returned.  What changed was the low-level wind pattern.  Almost all our summer moisture comes from the Gulf of Mexico and subtle changes in moisture advection from the south can radically alter how much moisture this area receives.

Although there has been a couple of exceptions, this summer has for now continued that pattern that started last summer with precipitation being near or below normal. If this continues through the entire summer will come down to variables we still can not forecast reliably for much beyond a week.

That Warm Spring

The National Climatic Data Center released their climate statistics for both May and the spring season last week.  Although Fargo Moorhead recorded the warmest spring on record, as a whole, both North Dakota and Minnesota ended up with the 2nd warmest spring since 1893.  The lower 48 states overall recorded the warmest spring on record as did a vast majority of the states east of the Rocky Mountains.

The previous year with the warmest spring was back in 1910 and that year still ranks as the warmest on record for North Dakota and Minnesota.  The main difference between these two very warm springs was that in 1910 the warmth was center just slightly north of where it was this year.  That slight difference was enough to keep the local states near, yet short of that record of 102 years ago, but did allow states to our south and east to edge out 1910 as the warmest.

Of note, both 1910 and 2012 were both very unique in the record books for the extreme warmth observed.

 

Late Frost Again

Although the official temperature in Fargo Moorhead stayed above freezing last Wednesday morning as the low was 35 degrees at Hector Int’l and 39 degrees at the Moorhead Municipal Airport, there were still areas of frost reported.  Some rooftops and car windows as well as low spots turned white as the temperature dropped to 32 degrees in those locations.

This was the 2nd year in a row with frost reported toward the end of May.  Last year the temperature dropped to 33 degrees on May 26 with frost reports far more widespread then this year.  Back in 2009 the temperature dropped to 34 degrees on June 6 and in 2008, the last frost occurred on May 27 with the low did hit the freezing point at 32 degrees.

I read many comments this past week that mentioned how surprised they were that a frost advisory had been issued so late in the season.  Yet, the truth is we may not technically hit 32 degrees at the airport, but a high percentage of the years this area will have a close call this time of year.

Spring 2012

May marked the end of climatological spring.  The three months of March, April and May were a period of phenomenal warmth with 74% of the days finishing with an above average daily temperature.  March finished as the warmest on record, April was the 13th warmest and May was the 11th warmest since 1881.

Combined, the three months ended up as the warmest spring in Fargo Moorhead on record.  Not only was the past spring the warmest on record, it surpassed the previous warmest spring on record (1977) by nearly 1 degree, which is impressive from a climatological perspective.

Overall, the spring of 2012 finished with an average temperature of 50.2 degrees.  That is 7.2 degrees above the current 30 year average.

The precipitation over the past three months was 4.91 inches, with nearly one-half of that falling on May 27 when 2.33 inches was recorded.  The current average spring precipitation is 5.47 inches.  Last year 21.5 inches of snow fell during the spring season, this year only 2.6 inches was measured.