We hear a lot about global warming and climate change. Ice sheets and glaciers are melting, the oceans are rising and extreme weather events such as tornadoes and floods, plus wildfires caused by drought, are common. I have been wondering for some time what the future climate of Arkansas might be. Toward that end, normalized data (30-year averages) for tornadoes, precipitation, and temperature were tabulated from data sets available on the Internet. Here are the results.
The number of tornadoes recorded each year is published by The Tornado History Project. From 1981 to 1996, the average was 21 tornadoes per year. From 1997 to 2017, tornado numbers increased to about 34 per year. The 2030 value was determined from the relationship between annual tornado numbers versus year from 1997 to 2017. By 2030, the predicted number of tornadoes is 45, or 11 more per year than 2017. Tornado Alley is moving into Arkansas.
The database for precipitation and temperature was from the National Oceanographic and Atmospheric Administration (NOAA). Precipitation data from 1967 to 2018 were used. The locations were Gravette, Mountain Home, Corning, Little Rock, Hope and Dumas. The predictions for 2030 precipitation were made based on a statistically significant fit of annual precipitation versus year from 1967 to 2018.
Precipitation minimums in inches occurred during the 1980s for Little Rock (48) and Dumas (50) and in the '90s for Gravette (43), Mountain Home (42), Corning (47), and Hope (51). These minimums were followed by maximums in 2018 for Little Rock (50), Gravette (47), Mountain Home (48), and Hope (54). The maximum for Dumas occurred in 2012 (52), while an increase of only 0.5 inch occurred at Corning. Predicted precipitation increases from 2018 to 2030 were greatest for Gravette, Corning, Mountain Home and Dumas, resulting in 53-, 52-, 51-, and 55-inch totals, respectively. Gains were smaller at Hope and Little Rock, where predicted 2030 totals were 55 and 51 inches, respectively.
The average minimum precipitation across the six locations from 1967 to 2018 was 47 inches; the average maximum was 50 inches. When the predicted precipitation increases are added to the latter, the maximum in 2030 is 53 inches. Dumas and Hope were specific locations with highest annual precipitation. Clearly, precipitation has increased in Arkansas in recent years, and likely will continue to increase in the future.
Temperature did decline and then increase in a pattern like precipitation described above. Insufficient data did not allow predictions for Mountain Home and Corning, so the following averages are for Gravette, Little Rock, Hope, and Dumas. From 1967 to 2018, the average temperature minimum was 60.8 degrees Fahrenheit, followed by a maximum of 61.8 degrees. The average predicted temperature from 2018 to 2030 is 62.4, so the state does appear to be slowly warming. Hope had the largest predicted increase (1.2), while Little Rock, Gravette, and Hope temperatures were predicted to increase by 0.5, 0.3, and 0.2 degrees, respectively. For the six areas of the state, no relationship between precipitation or tornado frequency and temperature was found for the 30-year norms.
In summary, the answer to the question posed in the subhead above is "yes." The likelihood is that Arkansas will have more tornadoes, more precipitation, and a small increase in annual temperature during the next decade or so.
John Gilmour is an emeritus professor of the Department of Crop, Soil and Environmental Science at the University of Arkansas at Fayetteville.
Editorial on 09/06/2019
Print Headline: JOHN GILMOUR: Weather watch