Flash Drought Surges During September

Flash drought continued to advance and intensify across the southwestern half of Oklahoma during September, aided by scorching hot weather and a prolonged dry spell that had stretched to more than 60 days in some areas. While there was some relief during September from the dry and hot conditions—the weather cooled considerably during the month’s second week to go along with heavy rains—summer weather returned soon thereafter for the remainder of the month. Despite the welcome moisture, the most significant rainfall continued to miss the worst of the drought plagued areas across southwestern and north central Oklahoma. Drought coverage increased from about 36% of the state at the end of August to nearly 47% at the end of September according to the U.S. Drought Monitor. Most of that 11% increase came in the “extreme” drought category, however, from 2% to nearly 13%. The Drought Monitor’s intensity scale slides from moderate-severe-extreme-exceptional, with exceptional being the worst category. In total, over 1.2 million Oklahomans were in at least moderate drought at the end of September, with over 200,000 of those in extreme drought.

The statewide average precipitation total for the month was 2.95 inches according to preliminary data from the Oklahoma Mesonet, 0.37 inches below normal and ranked as the 64th driest September since records began in 1895. Pockets of very heavy rainfall occurred from the eastern Panhandle into northwestern Oklahoma, and again across the eastern one-third of the state. Totals ranged from 9.96 inches at Talihina to 0.59 inches at Boise City. Monthly deficits ranged from 1-2 inches in general across much of the main body of the state in addition to the western Panhandle, while surpluses of 2-4 inches occurred across northwestern and eastern Oklahoma. Nineteen of the Mesonet’s 120 sites received at least 5 inches of rain during the month, and another 10 recorded at least 4 inches. Fifty-eight sites finished with totals of less than 2 inches, however. The first nine months of the year were 0.14 inches above normal statewide at 28.71 inches, the 46th wettest January through September on record. Totals during that period ranged from 13.48 inches at Hollis to 53.16 inches at Mt. Herman.

The statewide average temperature was 76.6 degrees according to preliminary data from the Oklahoma Mesonet, 3.7 degrees above normal and ranked as the 16th warmest September since records began in 1895. As was the case through summer, the southwestern corner’s heat was a step above the rest of the state with an average of 79.3 degrees, 4.5 degrees above normal and ranked as the ninth warmest September for that region. Temperatures ranged from 108 degrees at Freedom and Hollis on Sept. 4 and again at Grandfield on Sept. 5, to 44 degrees at Kenton on Sept. 25. The month’s—and possibly 2023’s—final spate of triple-digit temperatures occurred on Sept. 23. Heat index values of at least 105 degrees were recorded 225 times by the Mesonet during September, reaching a maximum value of 115 degrees at Idabel on Sept. 6. The first nine months of the year were the 20th warmest on record at 65 degrees, 1.2 degrees above normal.

The October outlooks from the Climate Prediction Center hold some hope for the dry areas of Oklahoma, including the long-term drought regions of north central and southwestern Oklahoma. The precipitation outlook shows increased odds of above normal precipitation for the western three-fourths of the state, especially across the southwestern corner and western Panhandle. The temperature outlook indicates warm weather should win out, especially across the northern two-thirds of the state. CPC’s October drought outlook predicts drought improvement for all but far southeastern Oklahoma through the month, with some complete drought removal likely.