October’s Drought to Deluge

The flash drought that had plagued the southwestern half of Oklahoma since mid-July appeared poised to explode across the entire state during October. As it began its northward advance, however, assistance arrived in the form of three distinct storm systems that not only halted the drought's advance but reversed its course. The first storm originated from the Tropical Pacific off the West Coast of Mexico. The remnants of Hurricane Norma journeyed over Mexico and into the Southern Plains on October 24, depositing 1-2 inches of tropical-style rain across parts of southern and central Oklahoma. This was swiftly followed by a more conventional storm system from the west that brought another round of rainfall to the state and ushered in significantly cooler weather. The last system arrived during the month's final weekend, accompanied by a blast of Arctic air, offering Oklahoma an early taste of winter. Freezing rain, mixed with sleet and snow, created hazardous driving conditions across the Panhandle and far northwestern Oklahoma on the 28th and 29th, while the rest of the state experienced a cold rain in blustery conditions. Another surge of cold air greeted Oklahoma's trick-or-treaters, leading to a frigid Halloween night with wind chills in the 20s and 30s on the evening of the 31st.

The statewide average precipitation total for the month stood at 3.88 inches, based on preliminary data from the Oklahoma Mesonet, surpassing the normal by 0.52 inches and ranking as the 37th wettest October since records began in 1895. The late-month storms contributed to surpluses of 3-6 inches across south central Oklahoma, making it the 15th wettest October on record for that region of the state, exceeding the normal by 2.92 inches. However, far northwestern Oklahoma and the eastern Panhandle received limited rainfall, resulting in deficits of 1 to 2 inches. Ardmore led the month with 9.74 inches of rainfall, while Beaver had the lowest total at 0.36 inches. An additional 31 sites of the Mesonet's 119 active locations recorded at least 5 inches of rainfall, while nine sites in the far northwest and Panhandle ended the month with less than an inch. The first ten months of the year concluded with a statewide average of 32.42 inches, surpassing the normal by 0.49 inches and ranking as the 42nd wettest January through October since records began in 1895.

The statewide average temperature for the month was 61.9 degrees, exceeding the normal by 0.6 degrees and ranking as the 60th warmest October on record. Temperatures ranged from 94 degrees at four separate sites during the month to 11 degrees at Kenton on October 30. This marked the lowest temperature recorded in the state since Eva dropped to 5 degrees on March 19 of this year. Wind chill values also reached their lowest levels since March during the late-month cold snap. Boise City recorded a wind chill of zero degrees on October 30, the lowest reading for the month. The statewide average for the first ten months of the year was 64.7 degrees, exceeding the normal by 1.1 degrees and ranking as the 19th warmest such period since records began in 1895.

Drought coverage had surged to nearly 50% of the state in early October, according to the U.S. Drought Monitor. Timely rains alleviated conditions in the middle of the month, but drought had started to advance northward once again before the end-of-month moisture arrived. The Drought Monitor's final report for October, on October 24, showed that 49% of the state was in at least moderate drought, with another 23% of the state experiencing abnormally dry conditions indicating areas at risk of further drought development. The precipitation that fell during the final week will be reflected in the following week's U.S. Drought Monitor report. The Climate Prediction Center's November drought outlook reflects these changes, with expected improvements in parts of south central and north central Oklahoma. Drought is anticipated to persist through November in other parts of the state. The temperature and precipitation outlooks predict above-normal temperatures with an equal probability of above-normal, below-normal, or near-normal moisture.