![]() The 16th started with well below zero readings in the northwest. There was clearing after dark, especially in the northwest. It was 4 degrees at Fayetteville (Washington County), Harrison (Boone County), and Highfill (Benton County), and 6 degrees at Mountain Home (Baxter County). High temperatures on the 15th were mostly in the single digits and teens. One of the coldest periods was the 15th into the 16th. In the picture: Temperatures were more than thirty degrees below average at times from February 14-20, 2021 at Little Rock (Pulaski County).įrom the 10th through the 20th, temperatures across Arkansas were ten to more than thirty degrees below average. This was the straw that opened the floodgates and almost guaranteed tumbling temperatures. Second, the Polar Vortex in the stratosphere (the next highest level in the Earth's atmosphere) rapidly declined in January. This indicated that tropospheric low pressure (Polar Vortex) toward the North Pole was weakening, with frigid conditions bottled up in Canada and nowhere to go but here. First, there was a long-term (more than two to three weeks) strongly negative Arctic Oscillation (AO) Index. There were two reasons it got ridiculously cold in February. ![]() The cold air builds up and has no place to go except into the United States. When the AO Index is strongly negative, especially for more than a few weeks, this implies that low pressure toward the North Pole (or the Polar Vortex) is weakening, and westerlies that carry cold air across Canada are not as strong. The negative phase continued into early February, 2021. ![]() In the picture: The Arctic Oscillation (AO) Index switched from positive to negative in December, 2020. There were four tornadoes (rated EF0/EF1), with one of these tearing through the north side of Fort Smith (Sebastian County) and Van Buren (Crawford County). This included areas from Russellville to Atkins (both in Pope County), Bismarck (Hot Spring County) to Benton (Saline County), and Walnut Ridge (Lawrence County) to Paragould (Greene County). On May 3rd/4th, there were several instances of 75 to more than 90 mph straight-line wind gusts across the northern and western counties. Seven tornadoes (rated EF0 to EF2) also occurred. These places are south/east of Little Rock (Pulaski County). ![]() The strongest damaging wind gusts and largest hailstones were concentrated during two notable severe weather episodes on March 27th and May 3rd/4th.ĭuring the afternoon and evening of March 27th, there was three inch diameter hail (slightly larger than baseballs) at South Bend (Lonoke County), baseball size hail at Gurdon and Whelen Springs (both in Clark County), and lime size hail at Newport (Jackson County) and Stuttgart (Arkansas County). (Hempstead Co.), Keo (Lonoke Co.), and Benton 10.9 WSW (Saline Co.) - Feb 18 20° at Fayetteville Drake Field (Washingtonħ1.50" at Cane Creek State Park (Lincoln Co.)ĩ.97" at Rohwer 2 NNE (Desha Co.) - Jun 9Ģ0.7" at Harrison 10.6 SW (Boone Co.) - Febġ4.2" at Arkadelphia 8.5 ESE (Clark Co.) - Feb 18ġ8" at Pine Bluff (Jefferson Co.), Hope 3 NE Two tornadoes in June and one in December were assigned ratings of EFU (unknown) because there was no damage to evaluate.ġ02° at Arkadelphia 2 N (Clark Co.) and Nimrod Across the state, this was one of only four tornadoes this strong since 2000. Seven people were killed, with two fatalities in Arkansas. The tornado went another 54 miles or so through southeast Missouri and northwest Tennessee before finally dissipating to the northeast of Samburg, TN. ![]() The strongest tornado (rated EF4/maximum winds around 170 mph) tracked over 26 miles through Monette (Craighead County) and Leachville (Mississippi County) on December 10th. The latest tornado (rated EF2) tore through Trumann (Poinsett County) on December 10th. Note: The yearly total of 35 tornadoes is slightly below the thirty year average of 37 tornadoes. ![]()
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