Drought expands despite historic rainfall

SEPT. 3, 2024

In a display of Oklahoma’s famously chaotic weather patterns, August brought historic rains to portions of central and eastern Oklahoma while drought continued to intensify and spread over other sections of the state. A remarkable 6 to 12 inches of rain fell from northwest to central Oklahoma within 12 hours on Aug. 11, with a volunteer observer near Noble in Cleveland County recording 11.01 inches— a 500-year rainfall event according to NOAA statistics. Oklahoma City set a new record for its highest single-day August rainfall at 6.58 inches, surpassing the previous mark of 5.06 inches set on Aug. 14, 2018. This also ranked as the city’s seventh-highest daily total for any month on record, dating back to 1890. The deluge caused widespread flash flooding, leading to flooded homes and businesses, road closures, and water rescues. Eastern Oklahoma also saw significant rainfall that day, with 4 to 8 inches falling in and around Muskogee County. Another heavy rain event of 4 to 8 inches occurred in far east-central Oklahoma on Aug. 16-17, primarily affecting Adair and Cherokee counties.

While these rains eradicated drought conditions locally, drought spread and intensified across other parts of the state. Images of dry farm ponds, dead or dormant pastures, and decimated crops emerged from the droughtafflicted regions. This deterioration was driven by extended periods without significant rainfall and persistent above-normal temperatures. Southwest Oklahoma had its ninth-warmest August since 1895, with temperatures averaging 4 degrees above normal thanks to nearly daily triple-digit highs. By late August, the region had gone 60 to 90 days without a quarter-inch of rain in a single day and over 40 days without even a tenth of an inch. According to the U.S. Drought Monitor, drought coverage more than doubled during August, rising from 22% at the end of July to 48% by the end of August— the highest amount of drought in the state since Oct. 23, 2023. Severe and extreme drought also expanded from 4% to 18%, primarily across the southwestern quarter of the state.

Oklahoma’s statewide average rainfall for August, as recorded by the Oklahoma Mesonet, was 2.8 inches— 0.43 inches below normal—ranking as the 65th-wettest August since records began in 1895. Mesonet rainfall totals varied significantly across the state, from a high of 10.56 inches at Cookson to just 0.06 inches at both Altus and Waurika. Notably, a volunteer observer near Bunch in Adair County recorded 13.04 inches, while another near Noble in Cleveland County reported 11.1 inches for the month. Thirty-two of the Mesonet’s 120 sites recorded at least 4 inches for the month, 17 of those above 5 inches. However, 47 sites saw less than 2 inches. For the climatological summer (June-August), the statewide average rainfall was 9.34 inches—1.35 inches below normal—ranking as the 54th-driest summer on record. Summer totals ranged from 17.33 inches at McAlester to just 1.14 inches at Mangum. The January-August average of 24.64 inches was 0.61 inches below normal, ranking as the 51st-wettest such period on record.

The statewide average temperature for August was 83 degrees, according to preliminary data from the Mesonet, 2.2 degrees above normal, making it the 31st-warmest August since 1895. Statewide, temperatures ranged from a high of 113 degrees on Aug. 23 and 24 at several locations to a low of 49 degrees at Eva on the month’s final day. The heat index reached a stifling 123 degrees on Aug. 18 at Okmulgee, with 15 other sites exceeding 115 degrees. Mesonet sites recorded heat index values of 110 degrees or higher 464 times during the month. The summer average temperature was 81.6 degrees—1.6 degrees above normal—ranking as the 21st-warmest on record. The first eight months of the year were the sixthwarmest since 1895, with an average temperature of 64.6 degrees, 2 degrees above normal.

The September outlook from the Climate Prediction Center offers some hope for parched areas in far southern Oklahoma. The temperature outlook predicts above-normal temperatures across most of the state, with higher odds in the far northwest, while the southeastern corner is expected to experience more typical conditions. The rainfall outlook show equal chances for above-, below-, or near-normal rainfall, except in far southern Oklahoma, where there are increased odds for above-normal precipitation. As a result, the CPC’s September Drought Outlook indicates potential drought improvement along the Red River, while drought conditions are expected to persist in other parts of the state.