Tornado Records Fall During May

Central Oklahoma has often been characterized as a haven for tornadoes, with some of that perception based in reality—and myth. There has been nothing mythical about that reputation in 2023, however. At least 11 tornadoes touched down in central Oklahoma on May 11, adding to persistent tornadic activity in that region during the previous 4 months of the year. Through just 5 months, the central Oklahoma counties of Cleveland and McClain broke their records for number of tornadoes in a calendar year with preliminary totals of 13 and 11, respectively. The previous record for Cleveland County was 7 in 2010, as well as for McClain County in 2011. The record calendar year total for any county remains 16 for Kingfisher County back in 1999, which all occurred during the infamous May 3 tornado outbreak. Additionally, the 28 tornadoes combined through May in Cleveland, McClain, and Pottawatomie counties smashed their previous record of 11, set in 2010 and 2015. Eight of those tornadoes were rated EF2 or higher. Another twister touched down in Kay County on May 12 for a preliminary total of 12 for the month, bringing the 2023 total up to 50 through May. Oklahoma averages 57.3 tornadoes in a calendar year, based off of data from 1950 through 2022.

The statewide average rainfall total finished the month at 4.09 inches, 0.84 inches below normal and ranked as the 53rd driest May since records began in 1895. Surpluses reigned across far western into central Oklahoma, but deficits of 2-4 inches were still widespread across the rest of the state. The Oklahoma Mesonet site at Hinton recorded the highest total of 8.36 inches, with the Panhandle site at Eva garnering an incredible 7.25 inches in second place, 5.3 inches above normal for that arid region. Tishomingo had the lowest total at 1.37 inches, 4.6 inches below normal for the month. Climatological spring—March 1 through May 31—finished with a statewide average of 9.45 inches, 1.85 inches below normal and ranked as the 42nd driest March-May on record. The statewide average for the first five months of the year was 13.21 inches, 1.35 inches below normal and ranked as the 65th driest January-May on record.

The statewide average temperature was 68.8 degrees for the month, 0.4 degrees above normal and ranked as the 46th warmest May since records began in 1895. A warm first half of the month buoyed that ranking despite milder conditions during May’s last half. The state’s highest temperature was 99 degrees at Altus on May 5 and 6, and again at Buffalo on May 7. There were no 90s recorded in the state between May 12-30, and 43 of the Mesonet’s 120 sites still had not reached 90 degrees by the end of the month. The lowest recorded temperature was 32 degrees at Lake Carl Blackwell on May 1 and again at Nowata on May 3, the latter being the last spring freeze for the state. Climatological spring ended as the 59th warmest on record and 0.4 degrees below normal at 59.3 degrees. The first five months of the year remained quite warm at 52.9 degrees, 0.8 degrees above normal and the 23rd warmest January-May on record.

Drought severity lessened significantly through the month, with the amount of extreme-to-exceptional drought dropping from 43% at the end of April to 25% at the end of May according to the U.S. Drought Monitor. However, at least 50% of the state was still in at least moderate drought at the end of May. The Drought Monitor’s intensity scale slides from moderate-severe-extreme-exceptional, with exceptional being the worst category. The June outlooks from the Climate Prediction Center call for increased odds of below normal temperatures across far western Oklahoma and the Panhandle, and above normal rainfall across the entire state, but especially across the western half. CPC’s June drought outlook indicates drought improvement across the entire Southern Plains—including Oklahoma—where it currently exists.