Spring is almost here, but severe weather season is already ramping up -- and AccuWeather forecasters say that tornado activity will shift into high gear in one particular month across the central and eastern U.S.
Published Mar. 9, 2022 10:33 AM EST | Updated Mar. 11, 2022 9:50 AM EST
The arrival of meteorological spring on March 1 also marked the opening chapter of severe weather season across the central United States, a season that AccuWeather predicts could spin up a higher number of twisters and life-threatening storms than what has unfolded in recent years.
Last year was turbulent in terms of severe weather. The 2021 severe weather season was strong right out of the gate with multiple outbreaks across the South in March. This was followed up by an unusually quiet April and then another active period once the calendar turned to May. The year was capped off with a "ridiculously active" December with a tornado outbreak on Dec. 10-11, which caused more than 90 fatalities, and then a rare and destructive derecho on Dec. 15.
Severe thunderstorms and tornadoes can happen at any time of the year, but the ingredients for powerful storms and large twisters come together most frequently in the central U.S. during March, April and May. This is why meteorologists consider these months to be severe weather season.
AccuWeather National Reporter Tony Laubach and his wife dropped everything they were doing to capture an evolving tornado on June 7, 2021. (AccuWeather / Tony Laubach)
There have already been previews of the brewing severe weather season with thunderstorms and isolated tornadoes in the central and eastern U.S. on Feb. 17, Feb. 22-23 and March 5-6. The outbreak on the first weekend of March turned deadly after an EF4 tornado tore through the Des Moines, Iowa, area destroying dozens of homes and leaving at least seven people dead.
One of the key characteristics of the 2022 severe weather season is that the worst of the storms may hit areas located outside of the traditional Tornado Alley.
A large shelf cloud, which is often associated with strong winds flowing out from a thunderstorm or line of thunderstorms, is visible over farmland.
Tornado Alley, a term coined in 1952 by Maj. Ernest J. Fawbush and Capt. Robert C. Miller of the U.S. Air Force, for decades, was used to refer to an area where there was a high potential for tornado development. The ingredients for tornadoes came together frequently in this region as Arctic air from the north clashed with warm, moist air from the Gulf of Mexico.
Hearing the term Tornado Alley may conjure up thoughts of storm chasers racing toward a towering thunderstorm in Oklahoma or Kansas, but trends in twisters in recent years have sparked debate among meteorologists as to whether the zone for most frequent tornadoes is shifting eastward.
The area historically referred to as Tornado Alley encompasses a swath of the southern Plains to the northern Plains that includes central Texas, much of Oklahoma, Kansas, Nebraska and South Dakota. On its western flank, this traditional Tornado Alley includes slivers of eastern Colorado and eastern New Mexico and, on its opposite side, a narrow slice of Iowa. But in recent years, the area with the most frequent tornadic activity has seemed to shift farther east toward the Mississippi and Tennessee valleys.
AccuWeather Senior Meteorologist Paul Pastelok and his team of long-range forecasters believe that there will still be twisters across the traditional Tornado Alley in 2022, but the worst of the storms and tornadoes may follow the recent trend and focus on areas farther to the east.
AccuWeather meteorologists approached the severe weather forecast in the same manner that they did when forging the annual spring forecast.
"Looking at severe weather this season, we do our research," Pastelok explained. This research entails analyzing the current weather patterns around the globe and comparing the current conditions to past years when there were similar weather patterns. This method can help meteorologists predict what is going to unfold in the future by studying the past.
Pastelok said when releasing the U.S. spring forecast that severe weather in March would ramp up fast, a forecast that has already come to fruition following the deadly tornado in Iowa on Saturday, March 5.
AccuWeather is forecasting between 120 and 170 tornadoes will touch down across the U.S. in March, which could be double the month's long-term average of 80 tornadoes, according to NOAA's Storm Prediction Center (SPC).
"There can be a few big events in March concentrated over the south-central Plains," Pastelok said, adding that there could also be severe weather events over the Gulf Coast states during the second half of the month.
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Unlike last season when there was a lull in the middle of the season, AccuWeather predicts that severe weather will be even more intense heading into April.
"April looks like a very active month," Pastelok warned. "That could be the most active as far as the number of tornadoes."
Between 200 and 275 tornadoes are forecast to spin up in April, significantly more than what unfolded last April, when 73 tornadoes were recorded, and well above the average of 155. The long-term averages are based on tornado data from 1991 through 2010, according to SPC.
The average numbers shown above are from data gathered between 1991 and 2010.
The most active month for tornadoes will also coincide with when storms begin to shift eastward.
This shift will be related to two big factors: the expanding drought conditions across the Four Corners and the High Plains and a change in the jet stream that will influence where severe thunderstorms can develop.
As of March 3, most of the traditional Tornado Alley was experiencing severe drought conditions with pockets of extreme to exceptional drought in the Texas Panhandle and western Oklahoma. Drought conditions can hinder the development of storms, creating a cycle that can cause the drought to become even worse.
This translates to a lower risk of storms in April, May and into the summer for places such as Lubbock and Amarillo in northwestern Texas. The reduced tornado risk will extend to Dodge City in southwestern Kansas and about 150 miles to the west for places like Lamar, which is in eastern Colorado, and, essentially, right through the heart of traditional Tornado Alley to North Platte, Nebraska, which is about 270 miles to the north of Dodge City. However, the drought will not completely eliminate the chances of occasional storms.
During this period, the higher risk of severe weather is predicted to occur across the Midwest, Mississippi Valley, Tennessee Valley and Ohio Valley, especially in April and May, instead of being focused on the traditional Tornado Alley.
The frequency of storms may throttle back heading into May with AccuWeather projecting between 140 and 190 tornadoes across the country. Typically, May features around 276 twisters as warm, humid air expands northward.
While the overall risk of intense storms and tornadoes will decrease somewhat heading into May, the threat area will expand to include more areas of the country.
"There may be fewer tornadoes in May, but severe weather can be more concentrated in the Midwest," Pastelok warned, adding that there could even be "an event or two in the mid-Atlantic and Northeast."
"A couple of severe events are possible in the Northeast in May, with the greatest threat of straight-line wind damage rather than tornadoes," Pastelok said. "Also, there can be some storms in the Midwest diving southeast, but overall May's tornado count may be down compared to April."
Stepping back to look at the bigger picture, AccuWeather is predicting a total of 1,350 to 1,475 tornadoes across the U.S. in 2022, above the annual average of 1,253, which is based on SPC data from 1991-2010. This could also potentially be the highest tornado count since 2019 when 1,517 twisters touched down.
While AccuWeather forecasters are predicting the number of tornadoes, they are not predicting the intensity of the tornadoes. Tornadoes are rated on the Enhanced Fujita (EF) scale, an updated version of the Fujita (F) scale which was named after the late meteorologist Dr. Ted Fujita, who developed the scale.
The U.S. is currently experiencing its longest stretch without an EF5 tornado, the highest and most extreme rating possible for a twister since reliable tornado records began in the 1950s.
The most recent EF5 tornado to touch down on U.S. soil took place nearly nine years ago on May 20, 2013, when a catastrophic, mile-wide tornado hit Moore, Oklahoma. The previous record for the longest period without an EF5 tornado was eight years between May 3, 1999, and May 4, 2007.
To be considered an EF5 tornado, damage survey teams from the National Weather Service must find evidence of winds of at least 200 mph.
The historic streak almost came to an end on Dec. 10, 2021, when a deadly tornado tracked across western Kentucky. Survey teams assessed the damage and determined the storm was a high-end EF4 tornado with peak winds of 190 mph, just 10 mph shy of making it into the record books as one of the most destructive forces of nature in U.S. history.
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