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State Climate Summaries

MISSOURI

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Hung Up on the Moon
Photo by Thomas Hawk

MISSOURI

 

Figure 1

Observed and Projected Temperature Change

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Observed and projected changes (compared to the 1901-1960 average) in near-surface air temperature for Missouri. Observed data are for 1900-2014. Projected changes for 2006-2100 are from global climate models for two possible futures: one in which greenhouse gas emissions continue to increase (higher emissions) and another in which greenhouse gas emissions increase at a slower rate (lower emissions). Temperatures in Missouri (orange line) have risen about 0.5°F since the beginning of the 20th century. Shading indicates the range of annual temperatures from the set of models. Observed temperatures are generally within the envelope of model simulations of the historical period (gray shading). Historically unprecedented warming is projected during the 21st century. Less warming is expected under a lower emissions future (the coldest years being about as warm as the hottest year in the historical record; green shading) and more warming under a higher emissions future (the hottest years being about 11°F warmer than the hottest year in the historical record; red shading). Source: CICS-NC and NOAA NCEI.

Missouri’s location in the interior of the North American continent exposes it to a climate with large ranges in temperature with hot, humid summers and cold winters. The lack of mountain barriers both to the north and to the south, and the state’s inland location away from the moderating effects of the oceans, allow it to be influenced by both cold Arctic air masses and warm, moist air masses from the Gulf of Mexico. Average annual temperatures across the state vary over a range of about 10°F from north to south. The year 2012 was the hottest on record, with an average annual temperature of 58.6°F, 4.1°F higher than the long-term average.

Since the beginning of the 20th century, temperatures in Missouri have risen approximately 0.5°F (Figure 1) and temperatures in the 2000s have been higher than any other historical period with the exception of the early 1930s Dust Bowl era. This warming has been concentrated in the winter and spring while average summer temperatures have not increased substantially in the state until the most recent 5 years, a feature characteristic of much of the Midwest (Figure 2). Due to extreme drought and poor land management practices, the summers of the 1930s remain the warmest on record. The recent summer warming has been characterized by much warmer nights (above “Dust Bowl” levels) while daytime highs have only increased a little. The state has also experienced a below average occurrence of extremely hot days (maximum temperature above 100°F) (Figure 3a). In addition to the overall trend of higher average temperatures, the state has experienced an above average number of very warm nights (minimum temperature above 75°F) (Figures 2 and 4). Since 1950, the annual number of these very warm nights has increased by about 2 days per decade at St. Louis Lambert Airport. Also, there is an upward trend in summer humidity since the mid-20th Century. The winter warming trend is reflected in a below average number of very cold nights (minimum temperature below 0°F) over the past 25 years (Figure 3b).

2

Figure 2a

 

Observed Summer Temperature

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Figure 2b

 

Observed Maximum Summer Temperature

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Figure 2c

 

Observed Minimum Summer Temperature

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Figure 2: The observed mean, maximum, and minimum summer temperatures for 1895–2014, averaged over 5-year periods; these values are averages from 24 long-term reporting stations. The dark horizontal lines represent the long-term average. Missouri experienced its highest summertime temperatures during the extreme heat of the 1930s “Dust Bowl” era. During the most recent 5-year period (2010–2014), summer temperatures have reached their highest levels since the 1930s. Both daytime highs and nighttime lows have been above average. However, the warming has been particularly notable in the nighttime lows as these have been the highest in the historical record, even higher than the 1930s. Source: CICS-NC and NOAA NCEI.

Figure 3

Figure 3a

 

Observed Number of Extremely Hot Days

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Figure 3b

 

Observed Number of Very Cold Nights

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Figure 3c

 

Observed Annual Precipitation

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Figure 3d

 

Observed Summer Precipitation

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Figure 3: The observed (a) number of extremely hot days (maximum temperature above 100°F), (b) number of very cold nights (minimum temperature below 0°F), (c) average annual precipitation, and (d) average summer precipitation, averaged over 5-year periods. The dark horizontal lines represent the long-term average. The values in Figures 3a and 3b are from 24 long-term stations. The values in Figures 3c and 3d are from NCEI's version 2 climate division dataset. The number of extremely hot days and the number of very cold nights have been predominantly below the long-term average in recent decades. Due to extreme drought and poor land management practices, the summers of the 1930s remain the warmest on record. Average precipitation has been generally above average since 1990, while summer seasonal precipitation has been variable, with no extended periods of above or below average levels. The driest 5-year period was 1952–1956 and the wettest was 2007–2011. Source: CICS-NC and NOAA NCEI.

Average annual precipitation varies widely across the state, from a low of 34 inches in the northwest to a high of 50 inches in the southeast. The northern part of the state receives more snowfall, with an annual average of 18–24 inches in the northern counties, compared to only 8–12 inches in the south. Annual statewide average precipitation has ranged from a low of 25.12 inches in 1953 to a high of 57.14 inches in 1973. The driest 5-year period was the early 1930s while the wettest 5-year period was the early 1990s (Figure 3c). Summer precipitation exhibits no trend (Figure 3d). For large portions of the state, more than 40% of the total annual precipitation occurs on the 10 wettest days of the year.

 

Observed Number of Very Warm Nights

Observed Number of Very Warm Nights

Figure 4: The observed number of very warm nights (annual number of days with minimum temperature above 75°F) for 1900–2014, averaged over 5-year periods; these values are averages from 24 long-term reporting stations. The dark horizontal lines represent the long-term average. During the 1930s, Missouri experienced a high frequency of very warm nights. This was followed by a cool period during the 1960s and 1970s. For the most recent 5-year period (2010–2014), Missouri has experienced the largest number of very warm nights since the extreme heat of the 1930s. Source: CICS-NC and NOAA NCEI.

Agriculture is an important component of Missouri’s economy; therefore, the state is particularly vulnerable to extreme precipitation conditions. Both floods and droughts can result in billions of dollars in losses. In 2012, a severe drought across the Midwest had large impacts on Missouri. Rainfall totals for the critical growth months of May, June, and July were several inches below average with only 5.76 inches of rain, the third driest such period (after 1901 and 1936) in 120 years of record. The drought was the worst Missouri had seen in 30 years; by the end of July, all 114 counties had been declared disaster areas.

Missouri has experienced an increase in the number of heavy rain events, and the state’s position in the lower river basins of several large Midwestern rivers makes downstream flooding an extreme hazard in this state (Figure 5). Missouri is ranked fourth in state losses due to flooding for the period of 1955–1997. One of the most severe climate events in the state’s history was the 1993 Mississippi River flood. Near St. Louis, the Mississippi River crested at 49.6 feet, almost 20 feet above flood stage, and 6 feet higher than the previous peak in April 1973. The flooding resulted in billions of dollars in damage to homes, businesses, agriculture, and infrastructure. In 2011, the state experienced flooding along both the Mississippi and Missouri Rivers. A wet April along the Ohio River Valley and record snowmelt in the upper Mississippi River basin caused record swelling along both the Ohio and Mississippi Rivers. To save the town of Cairo, Illinois, a levee was destroyed near Birds Point, flooding hundreds of thousands of acres of Missouri farmland. Property and crop damages were estimated at around $320 million. In June of that year, runoff from a record winter snowpack in the northern Rockies, combined with heavy rains, caused major flooding along the entire length of the Missouri River.

 

Observed Number of Extreme Precipitation Events

Observed Number of Extreme Precipitation Events

Figure 5: The observed number of days with extreme precipitation events (annual number of days with precipitation above 2 inches) for 1900–2014, averaged over 5-year periods; these values are averages from 28 long-term reporting stations. The dark horizontal lines represent the long-term average. A typical station experiences 2–3 days annually with 2 inches or more of precipitation. Over the past three decades, Missouri has experienced an above average number of extreme precipitation events, with the highest number occurring during 2005–2009 when a typical station experienced 3–4 such events each year. Source: CICS-NC and NOAA NCEI.

Severe thunderstorms are common in Missouri. During the summer, the state’s lack of geographic barriers allows cold, dry air from the north to collide with warm moist air from the Gulf of Mexico, triggering severe thunderstorms, which can produce high winds, heavy rain, tornadoes, and hail. On April 10, 2001, a strong thunderstorm produced catastrophic hail damage across the I-70 corridor. The storm produced hail as large as three inches in diameter, and damages in the Kansas City and St. Louis areas were estimated at around $1.5 billion. Missouri has a long and deadly history of tornadic storms. On May 22, 2011, an EF-5 tornado with winds exceeding 200 mph hit the city of Joplin, killing more than 150 people and causing billions of dollars in damages. This was the deadliest tornado in Missouri history. On March 18, 1925 the Tri-State Tornado, the deadliest tornado in U.S. history, tracked more than 200 miles from southeastern Missouri, across southern Illinois, and into Indiana. In Missouri, the storm killed at least 11 people and caused extensive property damage, including near complete destruction of the town of Annapolis.

Under a higher emissions pathway, historically unprecedented warming is projected by the end of the 21st century (Figure 1). Even under a pathway of lower greenhouse gas emissions, average annual temperatures are projected to most likely exceed historical record levels by the middle of the 21st century. However, there is a large range of temperature increases under both pathways and under the lower pathway a few projections are only slightly warmer than historical records. In southern Missouri, the annual maximum number of consecutive days with temperatures exceeding 95°F is projected to increase by up to 20 days. Temperature increases will cause future heat waves to be more intense, a concern for this region which already experiences hot and humid conditions. Extreme heat is of particular concern for urban areas, such as St. Louis and Kansas City, where the urban heat island effect raises summer temperatures. In 1966, St. Louis experienced a severe heat wave from July 9 to 14 which caused many deaths. In addition to daytime highs between 101°F and 106°F at St. Louis Lambert International Airport, nighttime temperatures never dropped below 77°F, and on July 12th, the low was only 84°F. If the warming trend continues, future heat waves are likely to be more intense, and cold wave intensity is projected to decrease.

Although projections of overall annual precipitation are uncertain, winter and spring precipitation are projected to increase, while summer precipitation may decrease (Figure 6). Additionally, extreme precipitation is projected to increase, potentially increasing the frequency and intensity of floods. Springtime flooding in particular could pose a threat to Missouri’s important agricultural economy by delaying planting and resulting in loss of yield.

The intensity of droughts is projected to increase. Even if precipitation increases in the future, rising temperatures will increase evaporation rates, resulting in more rapid loss of soil moisture. Thus, future summer droughts, a natural part of the Missouri climate, are likely to become more intense.

 

Projected Change in Spring Precipitation

Projected Change in Spring Precipitation

Figure 6: Projected change in spring precipitation (%) for the middle of the 21st century compared to the late 20th century under a higher emissions pathway. Hatching represents areas where the majority of climate models indicate a statistically significant change. Projected increases in spring precipitation are part of a large area of projected increases in the Northeast and Midwest. Source: CICS-NC, NOAA NCEI, and NEMAC.

Lead Authors:
Rebekah Frankson, Kenneth E. Kunkel
Contributing Authors:
Sarah Champion and Brooke C. Stewart
Recommended Citation:
Frankson, R., K. Kunkel, S. Champion and B. Stewart, 2017: Missouri State Climate Summary. NOAA Technical Report NESDIS 149-MO, 4 pp.

Resources

  1. Brown, P.J. and A.T. DeGaetano, 2013: Trends in U.S. Surface Humidity, 1930-2010. J. Appl. Meteor. Climatol., 52, 147–163, http://dx.doi.org/10.1175/JAMC-D-12-035.1.
  2. Changnon, S. A., K. E. Kunkel, and K. Andsager, 2001: Causes for record high flood losses in the central United States. Water International, 26, 223-230.
  3. Changnon, S.A. and J. Burroughs, 2003: The tristate hailstorm: The most costly on record, Monthly Weather Review, 131, 1734-1739pp. [Available online at http://journals.ametsoc.org/doi/abs/10.1175//2549.1]
  4. Kunkel, K.E, L.E. Stevens, S.E. Stevens, L. Sun, E. Janssen, D. Wuebbles, S.D. Hilberg, M.S. Timlin, L. Stoecker, N.E. Westcott, and J.G. Dobson, 2013: Regional Climate Trends and Scenarios for the U.S. National Climate Assessment. Part 3. Climate of the Midwest U.S., NOAA Technical Report NESDIS 142-3, 95 pp.  [Available online at https://www.nesdis.noaa.gov/content/technical-reports]
  5. Midwestern Regional Climate Center, cited 2016: “(1981-2010) Maps of gridded data long-term averages; Average Temp – St. Louis.” [Available online at http://mrcc.isws.illinois.edu/CLIMATE/]
  6. NOAA, cited 2011: State of the Climate: Global Hazards for May 2011, published online June 2011, retrieved on December 22, 2016, National Oceanic and Atmospheric Administration National Centers for Environmental Information. [Available online at http://www.ncdc.noaa.gov/sotc/hazards/201105]
  7. NOAA, cited 2016: 1925 tornado, NOAA/NWS 1925 Tri-state Tornado web site--tornado track, National Oceanic and Atmospheric Administration National Weather Service. [Available online at http://www.weather.gov/pah/1925Tornado_tt]
  8. NOAA, cited 2016: 2011 Tornado Information, Preliminary tornado statistics including records set in 2011, National Oceanic and Atmospheric Administration. [Available online at http://www.noaanews.noaa.gov/2011_tornado_information.html]
  9. NOAA, cited 2016: Climate at a Glance: U.S. Time Series, published October 2016, retrieved on October 18, 2016, National Oceanic and Atmospheric Administration National Centers for Environmental Information.  [Available online at http://www.ncdc.noaa.gov/cag/]
  10. NOAA, cited 2016: Climate of Missouri, National Oceanic and Atmospheric Administration. [Available online at https://www.ncdc.noaa.gov/climatenormals/clim60/states/Clim_MO_01.pdf]
  11. NOAA, cited 2016: National Overview - May 2011 Flooding, National Oceanic and Atmospheric Administration. [Available online at http://www.ncdc.noaa.gov/sotc/national/201105/supplemental/page-3]
  12. NOAA, cited 2016: State of the Climate: Tornadoes for Annual 2011, published online January 2012, retrieved on December 22, 2016, National Oceanic and Atmospheric Administration National Centers for Environmental Information. [Available online at http://www.ncdc.noaa.gov/sotc/tornadoes/201113]
  13. NOAA, cited 2016: This month in climate history: May 27, 1896, St. Louis tornado, National Oceanic and Atmospheric Administration. [Available online at http://www.ncdc.noaa.gov/news/month-climate-history-may-27-1896-st-louis-tornado]
  14. Southard, R.E. and B.J. Smith, 1995: Flood of 1993--Mississippi River Near the Jefferson National Expansion Memorial (Arch), St. Louis, Missouri, Fact Sheet FS-188-95, United States Department of the Interior, United States Geological Survey. [Available online at http://mo.water.usgs.gov/fact_sheets/fs-188-95-southard/report.pdf]
  15. USDA, cited 2016: 2012 Missouri drought information (archived content), Natural Resources Conservation Service Missouri, United States Department of Agriculture. [Available online at http://www.nrcs.usda.gov/wps/portal/nrcs/detail/mo/home/?cid=stelprdb1080895]
  16. USGS, 1995: Flood of 1993—Mississippi River near the Jefferson National Expansion Memorial (Arch), St. Louis, Missouri, Fact Sheet FS-186-95, 2pp., United States Geological Survey Missouri Water Science Center. [Available online at https://pubs.usgs.gov/fs/1995/0188/report.pdf]
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