A powerful winter storm pounded the state on 2020’s final day, a fitting epitaph to a tumultuous year—and a wintry December. The storm lasted into the first morning of 2021 and brought widespread totals of 2-6 inches of snow from southwestern into northeastern Oklahoma. Localized areas in central Oklahoma reported up to 10 inches of snow. The storm was the last in a series of four impactful winter systems that struck the state during December, and the fifth of the season. The month’s first storm dumped 10-15 inches of snow in far northwestern Oklahoma between Dec. 2-3. Two more storms traversed the state in quick succession on Dec. 13 and Dec. 15. The northwest was again the big winner between the two storms with over a foot of snow reported in Woodward and Ellis counties. Fargo and Arnett led official December totals at 27.1 inches and 26 inches, respectively, with Vici close behind at 25.5 inches. Fargo’s tally is the third highest December total in state history, behind Beaver’s 35 inches in 1911 and Goodwell’s 28 inches in 1918. Arnett’s total ranks fifth all-time. The highest Oklahoma snow total for any month remains Kenton’s 46 inches from February 1903. Arnett’s 32.3 inches—including 6.3 inches from a late October winter storm—led this season’s totals through December.
The statewide average precipitation total finished at 2.84 inches according to preliminary data from the Oklahoma Mesonet. That ranks the month as the 22nd wettest December since records began in 1895, 0.78 inches above normal. The entire state saw near or above normal precipitation for the month, save for the far western Panhandle where deficits continued to accumulate. Heavy rains provided surpluses of 2-4 inches in far southeastern Oklahoma. Broken Bow’s 8.22 inches led the December totals. Boise City had the lowest total at 0.22 inches. The statewide average total for 2020 was 39.71 inches, 3.21 inches above normal, to rank as the 20th wettest year on record. Annual rainfall varied tremendously across the state, however. Southeastern Oklahoma’s average of 65.43 inches was 14.84 inches above normal to rank as their seventh wettest annual total on record, while the Panhandle saw a deficit of 4.05 inches for their 25th driest. Individually, The Mesonet site at Mt Herman had 2020’s highest total at 77.86 inches, 23.1 inches above normal. Boise City’s 10.16 inches was the lowest, and 8.4 inches below normal.
December was warmer than normal despite the wintry intrusions throughout the month. The statewide average temperature was 40.8 degrees, 1.9 degrees above normal, to rank as the 45th warmest December on record. The Mesonet site at Centrahoma recorded December’s highest reading with 80 degrees on the ninth. Hooker and Beaver shared the lowest reading of 2 degrees on the 14th and 16th, respectively. The 2020 temperature extremes ranged from 1.2 degrees at Tipton on Feb. 6 to 113 degrees at Hollis on July 14. The 2020 statewide average was 60.7 degrees, 0.8 degrees above normal, to rank as the 28th warmest year on record.
There was virtually no change in the U.S. Drought Monitor depiction for Oklahoma throughout December, with a little over 25% of the state categorized in at least moderate drought. The heaviest moisture fell outside the hardest hit areas in western and southern Oklahoma, and the far western Panhandle. Improvements were expected in 2021’s first map due to the moisture-laden storm that ended the year. The Climate Prediction Center’s (CPC) January outlooks indicate increased odds of above normal temperatures across the entire state, and above normal precipitation over the eastern half of Oklahoma—especially the eastern one-third. CPC’s January drought outlook calls for drought persistence in those areas where it exists across western Oklahoma, but drought removal in the south central section of the state. No drought development is likely during January according to CPC’s outlook.