Quarterly Climate Impacts 

and Outlook

Southern

September 2018

National – Significant Events for August and Summer, 2018

Highlights for the Region

Temperatures varied spatially 

throughout the Southern Region. Most 

of the region experienced above normal 

temperatures, with an area near the 

Mississippi, Louisiana, and Arkansas 

borders experiencing below normal 

temperatures. Summer precipitation also 

varied spatially throughout the Southern 

Region. Parts of Texas, Arkansas, and 

Louisiana received 50 percent or less 

of normal precipitation while parts of 

northwestern Oklahoma and southern 

Texas received 200–400 percent above 

normal precipitation. The main climate 

impacts for summer in the Southern 

Region were extreme precipitation 

and drought. Every state experienced 

precipitation events with values 150 

percent or more above normal, while 

drought increased across the region.

The average U.S. temperature during August was 73.6°F, 1.5°F above average. 

The summer average U.S. temperature was 73.5°F, 2.1°F above average, and the 

fourth warmest on record. The August U.S. precipitation was 2.99 inches, 0.37 

inch above average. The summer average U.S. precipitation was 8.95 inches, 0.63 

inch above average.

Regional – Climate Overview for June to August 2018

Temperature and Precipitation Anomalies

Departure from Normal (F) 

6/01/2018–8/31/2018

Overall, average temperatures 

throughout the Southern Region were 

between 2°F below to 5°F above 

normal for the period spanning from 

June to August 2018. There were areas 

of 4–5°F above normal temperatures 

in western and central Texas. There 

were areas in northeastern Louisiana, 

western Mississippi, and southeastern 

Arkansas that were 1–2°F below 

normal.

Percent of Normal (%)

6/01/2018–8/31/2018

Summer precipitation varied spatially 

throughout the Southern Region 

for the period from June to August 

2018. Areas in central, western, 

and southern Texas, southwestern 

Arkansas, and northwestern Louisiana 

received 50 percent or less of normal 

precipitation. In contrast, areas 

of northwestern Oklahoma and 

southern Texas received 200–300 

percent of normal precipitation.

Streamflows

August average streamflow 

versus historical streamflow

The above figure illustrates August 

average streamflows in the Texas 

Gulf and Lower Mississippi Basins as 

compared to historical streamflows. 

Streamflows in southern Louisiana 

and Arkansas are near normal. Parts 

of central and southern Texas and 

northern Mississippi are experiencing 

below normal streamflow. In contrast, 

northeastern Texas is experiencing 

above normal streamflow.

Southern Region Quarterly Climate Impacts and Outlook | September 2018

https://www.drought.gov/drought/resources/reports

Contact: Derek Thompson (dthompson@srcc.lsu.edu)
Regional Impacts — For June to August 2018

Extreme Precipitation and Drought

This summer, the Southern Region was exposed to precipitation extremes, both in terms of above and below normal 

precipitation. Even though precipitation varied across the Southern Region for the period from June to August, every 

state experienced precipitation events with totals at least 150 percent above normal. In June, areas in northern, western, 

southeastern, and southern Texas as well as areas in central and southeastern Tennessee experienced precipitation 200 

to 400 percent above normal. Far southern Texas experienced precipitation 400 to 800 percent above normal, and 

Tennessee experienced the 21st wettest June on record (1895-2018). In July, eastern and part of western Texas as well 

as far northwestern Oklahoma experienced precipitation 200 percent above normal. In August, northeastern Texas, 

western, northeastern, and southeastern Arkansas, northwestern Tennessee, and eastern, northeastern and northwestern 

Oklahoma experienced precipitation 300 percent or more above normal. Arkansas experienced the 8th wettest August 

on record, and every state except for Louisiana recorded a wetter than normal August, with the region as a whole 

experiencing the 27th wettest August on record (1895-2018). Despite these extreme precipitation events, drought 

worsened across parts of the region. Compared to the end of May, the total area not experiencing drought conditions 

decreased to less than 50 percent, while the areas experiencing moderate and severe drought increased.

Above: Percent of normal precipitation in June (left), in August (middle), and August drought conditions (right).

CPC –Three-Month Outlook

Temperature Precipitation

Outlook for October to December

A = Above normal temperatures EC = Equal chances 

B = Below normal rainfall N = Normal

According to the Climate Prediction Center, October through December 

temperatures for the Southern Region are expected to be above normal. 

Chances are highest in far western and northwestern Texas and decrease from 

west to east across the region.

There is an equal chance of above or below normal precipitation from 

October through December across Tennessee, northern Mississippi, central and 

northern Arkansas, and northeastern Oklahoma. Much of Texas and southern 

Louisiana have the highest chance of experiencing above normal precipitation, 

with chances decreasing from south to north.

 El Niño Outlook

NOAA’s Climate Prediction Center 

is calling for a 60 percent chance of El 

Niño developing during the fall. Should 

El Niño develop, the Southern region 

could experience cooler than normal 

temperatures as well as higher than 

normal precipitation, especially during 

the winter.

Gulf Regional Partners

Contact: Derek Thompson (dthompson@srcc.lsu.edu)

#regionalclimateoutlooks

Southern Region Quarterly Climate Impacts and Outlook | September 2018 

https://www.drought.gov/drought/resources/reports

Earth Scan Laboratory at Louisiana State 

University (esl.lsu.edu)

NOAA/NWS Climate Prediction Center 

(cpc.noaa.gov)

NOAA/NOS Gulf of Mexico Coastal Services 

Center (csc.noaa.gov)

NOAA Gulf of Mexico Collaboration Team 

(regions.noaa.gov)

NOAA/NESDIS National Centers for 

Environmental Information (ncei.noaa.gov)

NOAA/NWS Southern Region (srh.noaa.gov)

Southern Climate Impacts Planning Program 

(southernclimate.org)

Southern Regional Climate Center 

(srcc.lsu.edu)