December Tornado Caps Record Year

Fri, Jan 03, 2020

Warm and mostly dry December weather dashed any hopes of walking in a winter wonderland, including dreams of a white Christmas. Very little in the way of wintry weather was seen during the month, save for a couple of inches of snow in the western Panhandle and a few bouts with freezing drizzle and fog. Christmas Day itself was the second warmest on record with a statewide average temperature of 57 degrees, topped only by 2016’s 57.6 degrees and far removed from 1983’s record cold of 4.7 degrees. Spring weather took up the slack for the dearth of winter excitement. A storm system moved through on December 27-28 and brought widespread beneficial rainfall across all 77 Oklahoma counties. Severe weather struck eastern Oklahoma on the 28^th and produced the year’s final tornado near Broken Arrow. The twister – rated an EF0 on the Enhanced Fujita Scale – damaged power poles, trees and a few structures.  The year’s 147 tornadoes are the most in Oklahoma since accurate records began in 1950, besting 1999’s previous record total of 145. May’s 105 tornadoes made up the bulk of the year’s record total, also the highest count for any month on record in the state. Despite the record number, there were no violent tornadoes – EF4 or EF5 – in the state during 2019.  

According to preliminary data from the Oklahoma Mesonet, the statewide average precipitation total was 1.11 inches, 0.95 inches below normal to rank as the 47^th driest December since records began in 1895. Far northwestern Oklahoma and the Panhandle enjoyed small surpluses to rank as their 39^th and 22^nd wettest Decembers on record, respectively. The southeast’s average total of 1.39 inches was 2.61 inches below normal to rank as their 14^th driest. Only three of the Mesonet’s 120 sites recorded more than 2 inches of rain for the month, with Cookson leading the state at 2.36 inches. Tipton had the lowest total with 0.44 inches. Despite the dry finish, 2019 managed to end as the eighth wettest year on record with a statewide average of 44.59 inches, 8.09 inches above normal. The year was easily the wettest on record for the northeast at 62.09 inches, 19.42 inches above normal, obliterating their previous record of 57.82 inches from 1973. Miami’s 2019 total of 81.64 inches led the state and became one of the highest recorded amounts in state history, as did Jay’s 80.67 inches. The National Weather Service cooperative observing station at Daisy has the record high total of 89.69 inches from 2015. The Mesonet site at Eva reported the lowest 2019 total with 13.65 inches. Forty-nine Mesonet stations recorded at least 50 inches of rainfall for the year.

The month was substantially warmer than normal. The statewide average of 43 degrees ranked as the 11^th warmest December on record, 4.1 degrees above normal. The average maximum temperatures were even higher, finishing 5-6 degrees above normal across parts of western Oklahoma. Boise City reported the highest single reading of the month at 77 degrees on the 23^rd. The lowest temperature of 8 degrees came on the 17^th at Kenton. That was the only single-digit reading at the Mesonet’s 120 stations during the month. The year came in exactly normal at 59.9 degrees, the 58^th warmest on record. The highest temperature for 2019 was 108 degrees from Hooker on August 19, while the lowest of minus 4 degrees was recorded at Eva on November 12. The lowest calculated wind chill was minus 17 degrees at Eva on January 2, and the highest heat index of 118 degrees came at Bixby on August 26.

The rain at the end of the month managed to halt any drought progression or intensification across western Oklahoma, despite the previous absence of moisture. Drought coverage had increased from 12% to 18% during December according to the U.S. Drought Monitor, before shrinking to a little more than 10% on the year’s final report. The amount of the state in abnormally dry conditions – signaling areas in danger of progressing to drought – shrank from 39% to 24%. The greatest extent of drought during 2019 came on the August 20 Drought Monitor at 24%. Drought was absent from the state for 27 weeks throughout the year, including 15 consecutive weeks from March 19 to July 23 – the longest such streak since 2010.

The Climate Prediction Center’s January outlooks show increased odds of above normal temperatures for all of Oklahoma save for the Panhandle, with those odds being greater in southeastern Oklahoma. Odds are even for above-, below- and near-normal precipitation over the entire state. CPC’s January Drought Outlook indicates the persistence of drought in the western Panhandle and southwestern Oklahoma, although the drought’s areal coverage should decrease somewhat in those areas.