Tornadoes Highlight October Weather

October’s weather was highly variable, and a bit too exciting at times as is usually the case during this transition period from summer to winter. Temperatures ranged from the teens to the 90s and rainfall totals fluctuated from double-digits to less than a quarter-inch. Flurries in the Panhandle as early as Oct. 11 brought the state its first snow of the season, although the sleds remained stored in the attic. The last of several cold fronts during the month provided trick-or-treaters with a chilly and sometimes damp search for candy. Severe weather seemed to get the most emphatic exclamation point of the month, however. Turbulent weather on the 21st brought severe winds, large hail and at least five tornadoes according to preliminary numbers from the National Weather Service. Twisters are not particularly uncommon during October. From 1950 through 2016, it had the fifth highest tornado count of any month with 130, and stands as the most active fall month. It is more uncommon to have a tornado strike a venue where The Beach Boys are performing, however. An EF1 tornado touched down on the east side of Newcastle and moved along State Highway 9 into the Norman area, striking the site of the concert at the Riverwind Casino. Minor damage was reported at the facility, and no injuries were noted. Another EF1 tornado moved through the northwest outskirts of Seminole, damaging homes and businesses. An additional three tornadoes were being investigated in southwest Oklahoma. The preliminary count for the year rose to 81 tornadoes, well above the 1950-2016 annual average of 56.

According to preliminary data from the Oklahoma Mesonet, the statewide average precipitation total finished at 3.43 inches, 0.11 inches below normal to rank as the 42nd wettest October since records began in 1895. Pawnee led the Mesonet with 10.95 inches for the month, more than 7 inches above normal. That surrounding area in the northeast saw widespread totals of 6-9 inches. Kenton measured a measly 0.16 inches, more than an inch below normal for that portion of the state. Twenty-nine of the Mesonet’s 120 stations recorded at least 5 inches of rain, and another 20 had at least 4 inches. Deficits of 1-3 inches were evident across northwestern and southern Oklahoma. The year was still on pace to finish significantly wet with a statewide average of 37.09 inches, 5.16 inches above normal to rank as the 12th wettest January-October since 1895.

Temperatures went on a roller coaster ride during October with wild swings between storm systems and fronts. Those extreme temperature variations were epitomized on Oct. 9 during the passage of a strong cold front. At one point that afternoon, the wind chill was 29 degrees in Boise City and the heat index was 97 degrees in Durant. The Mesonet’s actual air temperatures during October ranged from 94 degrees at Idabel and Valliant to 18 degrees at Buffalo on the 28th. The season’s first freeze occurred on Oct. 10 in the far northwest. Most of the state had experienced a hard freeze (at or below 28 degrees) by the end of the month. The statewide average for October finished 0.7 degrees above normal at 61.6 degrees, although that ranked as the 57th coolest on record. The year remained on the warm side with a January-October statewide average of 64.7 degrees, 1.6 degrees above normal and the 18th warmest such period on record.

The Climate Prediction Center (CPC) issued a La Niña watch during September, placing odds of its occurrence during the winter at 70 percent. That phenomenon, signified by cooler than normal equatorial waters off the western coast of South America, tends to bring the Southern Plains warmer, dryer winters. Given that possibility, CPC’s outlooks for November began to reflect those impacts. The November temperature outlook indicated increased odds for above normal temperatures across the entire state. The precipitation outlook was for increased odds of below normal precipitation across all but the far northeastern corner. Drought, which had decreased to a mere 3 percent of the state during October, was expected to persist in those areas but no further development was expected through November.