Tornadoes Top Weather Story During May
Associate State Climatologist
Oklahoma Climatological Survey
Even though severe weather only struck on a few days during May, those instances gave the month more than its money’s worth. The most violent weather occurred on May 24 when several long-track violent tornadoes tore their way through Oklahoma from west to east. While the exact details of the twisters are still being discovered, their 10 confirmed fatalities are unfortunately all too certain. Those casualties make the month the deadliest due to tornadoes in Oklahoma since May 1999. One of those deadly tornadoes clipped the Oklahoma Mesonet site northwest of El Reno just minutes after killing five people on and north of Interstate 40. The site’s instruments recorded a maximum wind gust of 151 mph during the tornado’s passage. The 151 mph wind gust tops the previous Mesonet record of 113 mph, recorded at the Lahoma site on August 17, 1994. Preliminary reports from the National Weather Service indicate at least 27 tornadoes touched down during May along with dozens of reports of golf ball- to softball-size hail. A National Weather Service research team from Topeka measured a 6-inch diameter hailstone near Gotebo on May 23, one of the largest stones ever reported in Oklahoma.
The other big weather story during May was the continuing drought in far western Oklahoma versus the excessively wet weather in the east. Much of the northwestern one-quarter of the state saw less than a half-inch of rain while the eastern one-third received 6-10 inches. Oklahoma City experienced its 13th wettest May since 1890 with 9.21 inches, a surplus of 3.77 inches. The extremes evened out for a statewide average of 4.37 inches, the 51st driest May since records began in 1895 at less than an inch below normal. The statewide average temperature was near normal at 67.8 degrees, the 55th coolest May on record.
The contrast in moisture from west to east is exemplified by comparing the weather fortunes of the northwest and southeast corners of the state. The Panhandle received an average of 0.33 inches during May, more than 3 inches below normal with a rank of fourth driest on record. Meanwhile, the southeast enjoyed a surplus of more than an inch at 7.71 inches, the 29th wettest May in that area. The Mesonet site at Vinita led the state’s rainfall totals with 12.52 inches. Boise City and Buffalo ended up at the other end of the gauge with totals of 0.19 inches. Grandfield was the warmest site in the state with an average temperature of 73.7 degrees and Boise City came in an unsurprising last with 60.6 degrees. The highest temperature of the month was 108 degrees at Altus on the 27th. The lowest temperature of 26 degrees was recorded at Boise City on the second.
The outlooks for June from the National Weather Service’s Climate Prediction Center indicate an increased chance for above normal temperatures in the southern two-thirds of the state and an increased chance for below normal precipitation in the southwestern two-thirds, including the Oklahoma Panhandle.