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State Climate Summaries

MISSISSIPPI

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Mississippi State Capitol - 1
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MISSISSIPPI

Mississippi is located on the coast of the Gulf of Mexico and on the southern end of the vast, relatively flat plains of central North America. The state is therefore exposed to diverse air masses, including the warm, moist air over the Gulf of Mexico as well as the dry continental air masses, which are cold in the winter and warm in the summer. Relatively mild winters, hot summers, and year-round precipitation characterize Mississippi’s climate. In addition to serving as a predominant source of moisture, the warm waters of the Gulf of Mexico help moderate temperatures along the coast. This mild climate is an important economic driver for agricultural production and tourism. Statewide average annual precipitation is about 56 inches, ranging from 50 inches in the north to about 65 inches along the coast. Historical observed extreme temperatures for the state range from -19°F at Corinth (January 30, 1966) to 115°F at Holly Springs (July 29, 1930).

 

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 Mississippi. 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 Mississippi (orange line) were warmest in the 1920s and 1930s and coolest in the 1960s through the 1980s. Temperatures have remained near average since the 1990s. 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), but on the very low end. If Mississippi were to continue to follow the low end of model projected temperatures, by the end of the 21st century temperatures would average about as warm as hottest historical year under a lower emissions scenario and about 4°F warmer than the hottest historical year under a high emissions scenario. Source: CICS-NC and NOAA NCEI.

Temperatures in Mississippi were highest in the 1920s and 1930s, followed by a substantial cooling of almost 2°F throughout the 1960s and 1970s (Figure 1). Temperatures have risen since that cool period by about 1.5°F, such that the most recent one to two decades have been slightly above the long-term average. Because of the large cooling that occurred in the middle of the 20th century, the southeastern United States is one of the few locations globally that has not experienced overall warming since 1900, while the United States as a whole has warmed by about 1.5°F. The United States as a whole also cooled from the 1930s into the 1960s, but not by nearly as much as Mississippi. Potential hypothesized causes for this difference in warming rates include increased cloud cover and precipitation, increased small particles from coal burning, natural factors related to forest re-growth, decreased heat flux due to irrigation, and multi-decade variability in North Atlantic and tropical Pacific sea surface temperatures. However, the year 2015 was the warmest on record, exceeding the previous record set in 1926.

A record number of extremely hot days occurred in the early 1950s, with an average of 10 days above 100°F each year. In the 21st century, there has been an average of about 3 such days per year (Figure 2a). The number of days below freezing (maximum temperature less than 32°F) was well above average in the 1970s and 1980s, but since then has been highly variable but mostly below average (Figure 2b). During the last ten years, both the number of very warm nights (minimum temperature above 75°F) (Figure 3) and the daily average summer temperature (Figure 4) have been above average, with a record number of very hot nights (an average of about 15.5 days per year) in the last 5-year period, a little above the previous record set in the 1930s (about 15 days per year).

Figure 2

Figure 2a

 

2a

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Figure 2b

 

2b

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Figure 2c

 

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Figure 2d

 

2d

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Figure 2: The observed (a) number of extremely hot days (maximum temperature above 100°F), (b) the observed number of days below freezing (annual number of days with daytime maximum temperature below 32°F), (c) the observed annual precipitation, and (d) observed summer precipitation, averaged over 5-year period. The values in Figures 2a and 2b are averages from 16 long-term reporting stations. The values in Figures 2c and 2d are from NCEI’s version 2 climate division dataset. The dark horizontal lines represent the long-term average. The number of extremely hot days has changed minimally over the last 60 years, and the number of days below freezing have generally been near to well below average for the past two decades (1990–;2014). Since the 1960s, average annual precipitation has generally been above average, although the last 10 years have been near average, while average annual summer precipitation has generally been near or above average since the late 1980s. Source: CICS-NC and NOAA NCEI.

 

Observed Number of Very Warm Nights

Observed Number of Very Warm Nights

Figure 3: 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 16 long-term reporting stations. The highest number occurred during the most recent 5-year period of 2010–2014, slightly above the previous record set in the early 1930s. The dark horizontal line is the long-term average of 9.8 days per year. Source: CICS-NC and NOAA NCEI..

 

Observed Summer Temperature

Observed Summer Temperature

Figure 4: The observed average summer temperatures for 1895–;2014, averaged over 5-year periods; these values are averages from NCEI’s version 2 climate division dataset. Average annual summer temperatures have been slightly above average over the last decade (2005–;2014), due in part to 2010 (warmest summer on record) and 2011 (3rd warmest). The dark horizontal line is the long-term average of 79.9°F. Source: CICS-NC and NOAA NCEI.

Average annual precipitation in Mississippi was generally above average from the 1970s into the early 2000s, but has been about average over the past decade (Figure 2c). Average summer precipitation has been near to above average since the late 1980s with the highest 5-year average on record occurring in the early 2000s (Figure 2d) although a few individual summers, including 2000 and 2006 have been quite dry. The driest 5-year period was 1952–;1956 averaging less than 48 inches per year while the wettest was 1971–;1975 averaging more than 65 inches per year. The annual number of extreme precipitation events (days with more than 3 inches) has been near the long-term average (1.5 events per station per year) in the last decade (Figure 5). Agricultural droughts during the summer are frequent occurrences in Mississippi. Since the creation of the United States Drought Monitor Map in 2000, Mississippi has only been completely drought-free for approximately 45% of the time from 2000 to 2014 and has had at least 50% drought coverage for approximately 12% of the time during the same period.

 

Observed Number of Extreme Precipitation Events

Observed Number of Extreme Precipitation Events

Figure 5: The observed number of extreme precipitation events (annual number of events with greater than 3 inches) for 1900–;2014, averaged over 5-year periods; these values are averages from 20 long-term reporting stations. Generally, the annual number of extreme precipitation events has been near to above the long-term average since the 1990s. The dark horizontal line is the long-term average of 1.5 days per year. Source: CICS-NC and NOAA NCEI.

Mississippi experiences an array of extreme weather events including severe thunderstorms, flooding, extreme heat, tornadoes, winter ice storms, and tropical cyclones (hurricanes and tropical storms). Between 2005 and 2014, a total of 13 FEMA disaster declarations were awarded to the state, 9 of which were for severe storms, tornadoes, and flooding events and the other 4 declarations were awarded in response to hurricanes. The typical flood season is November through June when the Mississippi River has its highest flow, although tropical cyclone flooding on smaller rivers occurs in the late summer and fall. Flooding of historic proportions occurred along the Mississippi River in the spring of 2011, following record snowmelt and unprecedented rainfall upstream of the state. Flood damage was estimated at $800 million in agricultural production for Mississippi alone.

Hurricanes can cause catastrophic damage. Hurricane Camille devastated parts of the state in 1969 as either the strongest (peak wind speed) or the second strongest (minimum pressure) storm (Category 5) to strike the United States in the 20th century. Damage estimates approached $950 million (1969 USD) for Mississippi. In 2005, Hurricane Katrina caused extensive damage along the coast of Mississippi as well as inland, including 238 fatalities and billions of dollars in damages. The storm surge at Pass Christian was 22.6 feet for Camille, and 27.8 feet for Katrina. Along the Mississippi coast, surges of approximately 15 feet have an average return period of 25 years, and surges of 20 feet and greater have an average return period of 50 to 100 years (Figure 6).

Pass Christian Coastal Surge Return Periods

Pass Christian Coastal Surge Return Periods

Figure 6: Storm surge at Pass Christian as a function of return period. For example, the storm surge of 27 feet recorded in Hurricane Katrina is expected to occur less than once every 100 years. Source: NOAA Southern Regional Climate Center.

Tornadoes are another important weather hazard for Mississippi. Over the past 30 years (1985–;2014), Mississippi has averaged 43 tornadoes annually, with 4 fatalities per year. The state ranks 12th nationally for the total number of reported tornadoes, but ranks as 1st in the nation in tornado deaths per million people. In the most recent decade (2005–2014), the state experienced its three highest annual number of tornadoes: in 2005 (about 100 tornadoes), 2008 (about 110 tornadoes), and 2011 (about 97 tornadoes). Tornadoes occur year-round, but there is a distinct tornado season with occurrences peaking in April and a second smaller peak in November.

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 (Figure 1). Since the 1970s, Mississippi temperatures have generally been within the range, but on the low end, of model-simulated temperatures. Warming is projected despite the lack of a long-term trend in Mississippi temperatures because the increased warming influence of greenhouse gases will become greater than the natural variations that have dominated Mississippi’s temperature climate.

Projected changes in summer precipitation for Mississippi are uncertain through mid-century (Figure 7). This is also the case for the other three seasons. However, future naturally-occurring droughts may be more intense because higher temperatures will increase the rate of loss of soil moisture during dry spells. During such droughts, decreased water availability will likely have important implications for the region and state’s agricultural economy.

Since 1880, global sea level has risen by about 8 inches. Sea level rise along the Mississippi coast may be even higher; the closest tide gauge with long-term data (Alabama’s Dauphin Island) reports a rise of more than 11 inches over the past century. Sea level rise has caused an increase in tidal floods associated with nuisance-level impacts. Nuisance floods are events in which water levels exceed the local threshold (set by NOAA’s National Weather Service) for minor impacts. These events can damage infrastructure, cause road closures, and overwhelm storm drains. Nuisance flooding has increased in all U.S. coastal areas, with more rapid increases along the East and Gulf Coasts. Nuisance flooding events in Mississippi are likely to occur more frequently as global and local sea levels continue to rise.

Sea level is projected to rise another 1 to 4 feet by 2100 as a result of both past and future emissions from human activities (Figure 8). Sea level rise has the potential to significantly damage critical transportation assets and negatively impact coastal resort communities along the Gulf Coast of Mississippi. Erosion of the barrier islands may further increase the potential impacts of sea level rise as these islands can shield the densely populated coastal areas, like Gulfport and Biloxi, from storm surge. The rate of erosion is increasing; for example, Ship Island has lost about 40% of its total area since 1970.

 

Projected Change in Summer Precipitation

Projected Change in Summer Precipitation

Figure 7: Projected change in summer precipitation (%) for the middle of the 21st century relative to the late 20th century under a higher emissions pathway. Hatching represents areas where the majority of climate models indicate a statistically significant change. While the map indicates slight decreases for Mississippi, these changes are minimal compared to natural variations and are not statistically significant. This is part of a large area of the Southeast where projected summer precipitation is uncertain. Source: CICS-NC, NOAA NCEI, and NEMAC.

 

Past and Projected Changes in Global Sea Level

Past and Projected Changes in Global Sea Level

Figure 8: Estimated, observed, and possible future amounts of global sea level rise from 1800 to 2100, relative to the year 2000. The orange line at right shows the most likely range of 1 to 4 feet by 2100 based on an assessment of scientific studies, which falls within a larger possible range of 0.66 feet to 6.6 feet. Source: Melillo et al. 2014 and Parris et al. 2012.

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

Resources

  1. Climate Central, cited 2016: Facts and Findings: Sea Level Rise and Storm Surge Threats for Mississippi. [Available online at http://slr.s3.amazonaws.com/factsheets/Mississippi.pdf]
  2. Climate change in Mississippi, cited 2016: [Available online at http://www.southernclimate.org/documents/climatechange_mississippi.pdf]
  3. FEMA, cited 2016: Disaster declarations for Mississippi, Federal Emergency Management Agency. [Available online at https://www.fema.gov/disasters/grid/state-tribal-government/50]
  4. Hurricane Science, cited 2016: 1969-Hurricane Camille. [Available online at http://www.hurricanescience.org/history/storms/1960s/camille/]
  5. Knabb, R.D., J.R. Rhome, and D.P. Brown, 2005: Tropical Cyclone Report: Hurricane Katrina: 23-30 August 2005, National Oceanic and Atmospheric Administration National Hurricane Center. [Available online at http://www.nhc.noaa.gov/data/tcr/AL122005_Katrina.pdf]
  6. Kunkel, K.E, L.E. Stevens, S.E. Stevens, L. Sun, E. Janssen, D. Wuebbles, C.E. Konrad II, C.M. Fuhrman, B.D. Keim, M.C. Kruk, A. Billet, H. Needham, M. Schafer, and J.G. Dobson, 2013: Regional Climate Trends and Scenarios for the U.S. National Climate Assessment. Part 2. Climate of the Southeast U.S., NOAA Technical Report NESDIS 142-2, 94 pp.  [Available online at https://www.nesdis.noaa.gov/content/technical-reports]
  7. Masters, J., cited 2016: U.S. Storm surge records (Hurricanes Camille and Katrina). [Available online at http://www.wunderground.com/hurricane/surge_us_records.asp]
  8. Melillo, Jerry M., T.C. Richmond, and G.W. Yohe, eds., 2014: Climate Change Impacts in the United States: The Third National Climate Assessment. U.S. Global Change Research Program, 841 pp. http://dx.doi.org/10.7930/J0Z31WJ2.
  9. NDMC, cited 2015: cited 2015: Percent Area in U.S. Drought Monitor Categories, The National Drought Mitigation Center. [Available online at http://droughtmonitor.unl.edu/MapsAndData/DataTables.aspx]
  10. Needham, H.F., and B.D. Keim, 2012: A Storm Surge Database for the U.S. Gulf Coast. International Journal of Climatology, 32,  2108-2123pp. http://dx.doi.org/10.1002/joc.2425.
  11. NOAA, cited 2015: State Climate Extremes Committee (SCEC), Records, National Oceanic and Atmospheric Administration National Centers for Environmental Information. [Available online at http://www.ncdc.noaa.gov/extremes/scec/records]
  12. NOAA, cited 2015: Storm Prediction Center WCM Page, National Oceanic and Atmospheric Administration Storm Prediction Center. [Available online at http://www.spc.noaa.gov/wcm/]
  13. NOAA, cited 2016: A look back at Hurricane Katrina, National Oceanic and Atmospheric Administration. [Available online at http://www.crh.noaa.gov/jan/?n=2005_08_29_hurricane_katrina_outbreak]
  14. 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/]
  15. NOAA, cited 2016: Climate of Mississippi, National Oceanic and Atmospheric Administration. [Available online at https://www.ncdc.noaa.gov/climatenormals/clim60/states/Clim_MS_01.pdf]
  16. NOAA, cited 2016: Continental United States hurricane impacts/landfalls 1851-2015, National Oceanic and Atmospheric Administration. [Available online at http://www.aoml.noaa.gov/hrd/hurdat/All_U.S._Hurricanes.html]
  17. NOAA, cited 2016: State of the Climate: Tornadoes for Annual 2014, published online January 2015, 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/201413]
  18. NOAA, cited 2016: Top 10 years for tornado fatality, National Oceanic and Atmospheric Administration. [Available online at http://www.srh.noaa.gov/jan/?n=top10yrs_tordeaths]
  19. Parris, A., P. Bromirski, V. Burkett, D. Cayan, M. Culver, J. Hall, R. Horton, K. Knuuti, R. Moss, J. Obeysekera, A. Sallenger, and J. Weiss, 2012: Global Sea Level Rise Scenarios for the United States National Climate Assessment. NOAA Tech Memo OAR CPO-1, 37 pp., National Oceanic and Atmospheric Administration, Silver Spring, MD. [Available online at http://scenarios.globalchange]gov/sites/default/files/NOAA_SLR_r3_0.pdf]
  20. Sherman-Morris, K. and C.L. Wax, 2012: Mississippi Weather and Climate, University Press of Mississippi, 224 pp. [Available online at http://www.upress.state.ms.us/books/1493]
  21. Simpson, R.H. and A.L. Sugg,1970: "The Atlantic Hurricane Season of 1969" (PDF). Monthly Weather Review, 98, 293S pp. http://dx.doi.org/10.1175/1520-0493-98.4.293.
  22. Strauss, B., C.Tebaldi, S. Kulp, S. Cutter, C. Emrich, D. Rizza, and D. Yawitz, 2015: Mississippi and the Surging Sea: A vulnerability assessment with projections for sea level rise and coastal flood risk. Climate Central Research Report. pp 1-30. [Available online at http://sealevel.climatecentral.org/uploads/ssrf/MS-Report.pdf]
  23. USACE, 1970: Report on Hurricane Camille, 14-22 August 1969. Mobile, Alabama, United States Army Corps of Engineers. [Available online at https://coast.noaa.gov/hes/docs/postStorm/H_CAMILLE.pdf?redirect=301ocm]
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