Tornadoes and their warnings have been few and far between in Kansas for the majority of 2020, and in one corner of the state a record is poised to be broken if the trend continues through the end of the year.
The National Weather Service office in Dodge City has recorded only six tornadoes across its 27-county forecast area — well below the annual average of 28.
Last year saw 29 tornadoes touch down across those counties.
“Going back to 1991, the lowest tornado count for our warning area was seven,” said Mike Umscheid, storm chaser and meteorologist for the Dodge City office. “If we don’t have any more tornadoes this year, we will break that 30-year record for lowest number of tornadoes.”
Statewide, the average number of tornadoes reported each year is 96, according to the National Oceanic and Atmospheric Administration. Umscheid said the most active tornado season his office has recorded was in 2008, when 81 twisters touched down across its warning area.
“It’s interesting how you can go from one extreme to another in the matter of a decade,” Umscheid said.
The most recent and notable tornado event in southwest Kansas occurred on July 1, when a twister touched down in northern Seward County. The only reported damage was to an irrigation sprinkler, and the tornado was later classified as an EF-1 on the Enhanced Fujita scale with wind speeds in the 80-90 mph range.
The amount of tornado warnings issued in Kansas is significantly lower this year, as well. Through Aug. 25, the NWS office in Wichita has issued only two tornado warnings for the counties it serves, on April 28 and June 21. Chance Hayes, the warning coordination meteorologist for NWS Wichita, said his office has averaged nearly 25 tornado warnings each year over the past decade.
“When you look at the seven offices which serve the state of Kansas, all seven average 218 tornado warnings a year in a period over the last 10 years,” Hayes said. “Right now, we are right around 57 for the year across the state, or about 25% of average.”
Tornadoes and other severe weather events are the products of supercell thunderstorms — huge rotating assemblies of cloud that require a clash of warm, moist air from the Gulf of Mexico, cool dry air from the Arctic, and plenty of low-level wind shear courtesy the jet stream. Bill Bunting, the chief of forecast operations for the Storm Prediction Center in Norman, Okla., said at least one of those key ingredients has been missing this year.
“The combination of factors that we look for, for favorable tornado situations, just didn’t occur very often,” Bunting said. “We actually had a good chunk of May and June with winds aloft from the north and west, which stabilized the lower atmosphere.”
Hayes said some meteorologists at the NWS Wichita office have been investigating those winds as the culprit behind the limited tornado season.
“One of the things they pointed to was airflow in middle and upper levels of the atmosphere is more from a northerly direction, which can lead to more convection and storms in the late night and overnight hours,” Hayes said. “This leads to heavy rains and flooding, hailstorms, and straight-line winds. It means the possibility for tornadoes is much less.”
Umscheid said the Gulf of Mexico’s sea surface temperature anomalies have been higher, so moisture has not been the problem.
“It’s all in the jet stream patterns,” Umscheid said. “It’s just a matter of getting those low-level winds to crank that wind shear over a large enough area.”
Umscheid, along with other atmospheric scientists, said climate change may partially explain the jet stream buckling more frequently.
“Anecdotally, there seems to be a subtle shift towards jet stream patterns which tend toward a more blocking nature,” Umscheid said. “I think a lot of that shift can be contributed to a warming of high arctic latitudes.”
Bunting said there have been studies which have looked at the degree to which a warming world would affect tornadic activity.
“The answer right now is inconclusive,” Bunting said. “You have basically a conflicting trend in two of the key parameters for tornado occurrence – instability and warm moist air. It really makes it difficult to reach a firm conclusion on the impact of climate change on tornado occurrence.”
Mary Knapp, state climatologist at Kansas State University, said atmospheric scientists are watching the development of a La Nina pattern in the Pacific Ocean. This phenomenon occurs when strong winds push warm water at the ocean’s surface from South America to near Indonesia, helping colder water rise from deeper levels to the surface of the Pacific. Knapp said this kind of pattern tends to favor hotter and dryer conditions in autumn months.
According to Hayes, there have been 108 tornadoes reported since 1950 over the months of September through December.
“We do have kind of a secondary season for severe weather,” Hayes said. “It’s part of that transition from summer to fall.”
Knapp said she hasn’t heard much complaining about the lack of tornadoes for 2020.
From a storm chasing perspective, Umscheid said, there have been fewer weather enthusiasts on the roads because of the COVID-19 pandemic, but there is still a need for ground confirmation of severe weather activity.
“If there have not been tornadoes for a couple years, you can kind of ‘set it and forget it’ and fall into this trap of false safety,” Umscheid said.
“I don’t think it’ll be a huge problem, because once we have another tornado outbreak in Kansas — which will happen — it will snap people back to being prepared.”