National Weather Service Weather Forecast Office

Comparison Between the Summer of 1980 and the Summer of 2012

In 1980, a heat wave claimed the lives of 157 people in the Kansas City and caused 443 heat related illnesses.  This year has been hot, but as of August 4th, there have only been 3 confirmed heat related deaths by the Kansas City Health Department.  According to the Missouri Department of Health & Senior Services in an article on Hyperthermia related illness, “In Missouri, the greatest numbers of heat-related deaths have occurred in the urban, more densely populated areas of St. Louis City, St Louis County and Jackson County (Kansas City). Of the 278 heat-related deaths reported from 2000 through 2011, there were 173 (62%) deaths in these metropolitan areas. Rural deaths accounted for 105 (38%) of the deaths.”  

This season has been abnormally hot, with the seasonal ridge setting up quite early in June, and persisting with little relief through the month of July.  This has brought a good portion of the Midwest a hot and dry summer.  This Summer and the Summer of 1980 were very similar in the fact that they both featured dry starts to the year.  Comparing this season to the summer of 1980, the summer of 1980 reached higher temperatures and heat indices, but this summer has been much drier.

In order to examine the differences between the two years, let's take a look at the comparisons between June-July 1980 and June-July 2012 with respect to temperatures recorded to this point.  During 2012 Kansas City has had 18 days with temperatures equal to or above 100˚F reported at the Kansas City Downtown Airport (MKC).  In 1980, through July 29, Kansas City experienced 25 days equal to or above 100˚F reported at MKC.  That summer a maximum temperature of 109˚F was recorded at the downtown airport, and the maximum temperature recorded at the downtown airport during June-July 2012 has been 107˚F.  When comparing low temperatures between 1980 and 2012, in 1980, as of July 29th, Kansas City recorded 18 days with overnight lows equal to or above 80˚F, with a season low of 59˚F.  This year Kansas City has had 9 days with overnight lows equal to or above 80˚F, with a season low of 49˚F on June 1st.

Comparing the heat index between 1980 and 2012, the difference in moisture is visible using the heat index, as the heat index combines moisture and temperature to compute the estimated apparent temperature outside.  As of July 29th, Kansas City has only had 11 days with heat indices above 105˚F.  In 1980, as of July 29th, Kansas City had experienced 28 days with heat indices above 105˚F.  The maximum heat index reached that year was 122˚F, which was reached on June 27th.  This year, the highest heat index Kansas City reached was 110˚F, on July 29th (as based on hourly temperature observations). 

 

 

The difference in dew point temperatures shows the difference in moisture very well.  Dew point temperature is the temperature at which water condenses at constant pressure.  The higher the dew point temperature (closer to the actual temperature), the more moisture content there is in the air.  In 1980, the average daily dew point temperature was 4˚F higher than this year.  The lowest daily high dew point recorded this year was also 4˚F lower than as of this time in 1980.

A large contributor to the difference in air moisture content is the difference in rainfall amounts between 1980 and 2012.  This summer the Kansas City area has received almost half the summer rainfall in 2012 than in 1980.  In 1980, Kansas City recorded 7.57 inches of rain from May through July.  This year has reported only 3.95 inches during that same period.  Comparing the total rainfall from January through July, Kansas City recorded 15.27 inches in 1980 and 13.63 inches in 2012.  These were both very dry years, with precipitation totals well below the normal for January through July, which is 23.51 inches.  This summer, though, has been much drier than 1980. 
 

 
The heat might have been more intense in 1980, but the heat this year spans a larger area, creating a more widespread event.  This is due to a much broader ridge parking itself over much of the CONUS this year, as compared to a smaller, more intense ridge in 1980.  Much of the heat anomaly this year is further north than in 1980, as well.  In 1980, the heat wave did not have a major impact north of South Dakota and Iowa.  This year the heat wave spans well into Canada, and even regions of northeastern and northwestern Canada.
 

850 Temperatures Anomaly - 1980	850 Temperatures Anomaly - 2012

The summer of 1980, as of July 29th, was hotter than the summer of 2012 has been so far.  It was both hotter in temperature and produced higher heat indices due to more moisture content at the surface.  This summer, though, has been much drier, with almost half the rainfall recorded in 1980.  This has made for a more severe drought, damaging crops and the agricultural industry throughout the Midwest.

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