Climate and Agriculture in the Southeast

September 2017 again near normal across most of the Southeast

For the second month in a row, temperatures across Georgia were near normal for the state as a whole, with the coolest temperatures in the northern half of the state and warmer temperatures farther south. The monthly rainfall for the state overall was near normal, but that was due to the combination of significant rain from Hurricanes Harvey and Irma and mostly dry conditions otherwise. The wettest part of the state by far was the southeast corner, which took the brunt of rainfall from Irma.

In Atlanta, the monthly average temperature was 73.8 degrees F (0.3 degrees above normal), in Athens 72.5 degrees (0.8 degrees below normal), Columbus 77.2 (0.6 degrees above normal), Macon 74.8 (0.2 below normal), Savannah 78.9 (2.0 above normal), Brunswick 79.7 (1.6 above normal), Alma 78.0 (0.8 above normal), Augusta 76.7 (2.1 above normal), Albany 78.2 (0.5 above normal), Rome 72.3 (0.3 above normal), and Valdosta 77.4 (0.0 degrees above normal).

A number of temperature records were set in September. Low minimum temperatures were set in Athens on September 7 and 8 (51 and 52 F), Columbus on September 8 (57 F), and Macon on September 7 and 8 (51 and 52 F), breaking records by one to four degrees. Low maximum temperature records were broken during the passage of Hurricane Irma on September 12, with Athens reaching only 64 F (old record was 67 F set in 1891), Columbus reaching 65 F (old record 74 F from 1935 and 1952), and Macon reaching 69 F on September 11 (old record 70 F from 1935).  Alma reported record low max temperatures on September 10 with 73 F (old record 76 F set in 1956. High temperature records were set in Augusta, with 97 F on September 28 tied with 1986, Alma on September 29 with 95 F beating the old record of 91 F set in 2016, and Brunswick on 9/28 with 93 F surpassing the old record of 91 F set in 1986.

The highest monthly total precipitation from National Weather Service reporting stations was 12.91 inches in Brunswick (7.15 inches above normal) and the lowest was in Valdosta with 2.34 (2.30 inches below normal).  Atlanta received 4.25 inches (0.22 inches below normal), Athens received 4.19 inches (0.25 inches above normal), Columbus received 3.19 inches (0.13 above normal), Macon 3.87 inches (0.28 above normal), Rome 4.60 inches (1.19 above normal), Savannah 5.59 inches (1.01 above normal), Augusta 4.28 inches (1.06 above normal), Albany 2.89 inches (0.55 below normal) and Alma 8.02 inches (4.38 inches above normal).

A number of rainfall records were also set in September from Hurricane Irma. Macon received 3.26 inches, beating the old record of 0.91 inches from 2016. Savannah received 4.74 inches, passing the previous record of 3.75 inches set in 1878, Augusta observed 4.10 inches, beating the old records of 2.30 inches from 1884, Alma received 5.72 inches, surpassing the old record of 1.367 inches from 1982, all on September 11. Brunswick observed 5.39 inches on September 10, much higher than the previous amount of 1.98 inches from 1964.

The highest daily rainfall total from CoCoRaHS observers was 9.57 inches near Nahunta in Brantley County on September 12, followed by 8.56 inches measured near Screven in Wayne County. Both of those were due to Hurricane Irma.  For the entire month, the highest total was 14.21 inches measured on St. Simons in Glynn County followed by 13.87 inches from an observer near Richmond Hill in Bryan County and 12.09 inches at Kingsland in Camden County.

The major severe weather event of the month was Hurricane Irma, which pushed a storm surge into coastal areas of Georgia, prompting an evacuation order from Governor Deal, and caused significant wind damage to power lines, trees and agriculture from gusts that were up to 62 mph high. While damage estimates are still coming in, power in some counties was lost for more than 50% of the population and took several days to restore. An estimated 30% of the pecan crop was lost due to downed trees and nuts and cotton yields were cut by 20% or more in some locations due to cotton blown out of bolls or damaged and twisted plants.  Isolated wind and hail damage from strong thunderstorms was reported on four additional days this month.

The wetter conditions in September were enough to remove all abnormally dry conditions from the state by the end of the month. No drought is expected to develop through the end of the year.

Agriculture took a beating from Hurricane Irma as noted above. In addition to the damage to pecans and cotton, delays in harvest associated with the wet ground may have reduced the quality of some peanuts. But dry conditions the rest of the month were generally good for hay producers and other folks out harvesting, although dry soil moisture at the end of the month may cause problems for producers trying to plant fall forage and small grains. Even with the losses from Irma, yields of cotton and pecans are expected to be reasonable because of the number of acres planted and the heavy load of pecans on the trees before the storm hit.

The outlook for October shows that warmer than normal conditions are expected this month, particularly in the first two weeks.  Precipitation is expected to be below normal, although a developing tropical system in the Gulf of Mexico could change that.  Tropical activity is expected to occur in the next month or two as the active Atlantic tropical season winds down, and that may bring rains to some locations while missing others. A La Nina watch has been issued for the next few months, and because of that, warmer and drier conditions than normal are expected to occur over the winter into spring, particularly in the southern half of the state.

For more information please see the “Climate and Agriculture” blog at http://blog.extension.uga.edu/climate/  or visit our web page at http://www.gaclimate.org.  We are now also on Facebook at SEAgClimate and on Twitter at @SE_AgClimate.  Please feel free to email your weather and climate impacts on agriculture to share on the blog to pknox@uga.edu.