The first three months of 2023 have proved unusually active — and deadly — for tornadoes, and the volatile pattern for severe weather shows little sign of settling down. Meteorologists are tracking a disconcerting atmospheric setup that could favor multiple bouts of high-end severe weather, with thunderstorm outbreaks and possible tornadoes in the South, Midwest and Corn Belt into early April.
May is historically the most active month for tornadoes, followed by June and then April. An average of 720 twisters spin up across the Lower 48 during that three-month stretch, often coming in swarms that can span multiple states and terrorize storm-weary residents who spend much of the spring holding their breath.
There’s been no shortage of tornadoes so far this year, with 168 recorded across the country in January, the second most on record. February bore witness to 55 twisters, twice the monthly average; at least one of them, an EF2, hit New Jersey in an unseasonable surprise. March, which started slowly, awakened suddenly with Friday’s devastating outbreak in Mississippi and may close with a widespread swath of dangerous storms on Friday.
Reed Timmer, a meteorologist and storm chaser, tweeted that models are highlighting a “pattern we see every 10 years or so,” which could persist for multiple weeks. He added a warning to his followers: “Time is now to mentally and physically prepare.”
Friday’s danger
On Thursday, a trough, or dip in the jet stream that ushered in the storm slamming California on Tuesday, will begin to push east from the Rockies. This may set off some thunderstorms capable of turning severe — especially in parts of the southern and central Plains — but it’s uncertain how widespread they’ll become.
But by Friday, storms will probably turn more numerous and violent.
As the powerful jet stream progresses eastward, warm, humid air will spread over the Corn Belt, parts of the Midwest and the Mississippi Valley ahead of it. That’s where a Level 3 out of 5 risk of severe weather has been drawn by the National Weather Service Storm Prediction Center. It includes Memphis, Little Rock, St. Louis, Springfield, Mo., and Des Moines. A surrounding Level 2 risk stretches from Chicago all the way south to near Dallas and Jackson, Miss.
“Potentially intense and widespread severe thunderstorms are expected Friday afternoon into the overnight hours across portions of the Middle Mississippi Valley and Mid-South vicinity, eastward to the Lower Ohio and Tennessee Valleys,” wrote Storm Prediction Center. “Damaging gusts and tornadoes will be the main hazards with this activity.”
There is a high ceiling with regard to the potential storm severity of this system. However, it’s unclear both how far north the warm, unstable air will progress and whether thunderstorms will organize into supercells — which spin and sometimes spawn tornadoes.
Andrew Pritchard, a senior meteorologist with Nutrien Ag Solutions, says it’s still unclear how the day will play out.
“What we don’t know is whether we’ll see pockets of rain or cloud cover that inhibit crucial hours of sunshine and otherwise mitigating the risk for severe thunderstorms by tempering the amount of available energy,” he wrote in a message to The Washington Post. “Or, do we wake up on Friday morning to a warm sector that is free of complicating factors and an environment that is primed for a severe weather outbreak?”
He also noted that uncertainty in the speed of the storm system means it’s unclear where the greatest risk of severe weather will materialize.
Looking ahead
Beyond this week’s setup, there are signs that suggest Monday into Tuesday of next week could feature another volatile atmospheric battle. That could lend itself to producing more dangerous weather, including in the zone that was devastated by Friday’s tornadoes.
“Severe potential could once again increase early next week across parts of the Arklatex into the Mid/Lower Mississippi and Tennessee Valley vicinity,” the Storm Prediction Center wrote in its longer-range outlook. “However, guidance is vastly different in the timing of this system and how far north or south the trough will be located.”
Thereafter, the first week or two of April looks busy, too.
In a message to The Post, Michael Ventrice, a meteorologist and software engineer, wrote that the prevailing pattern of cold, stormy weather in the West and abnormal warmth in the East — favorable for severe weather in the central states and the South — shows little sign of breaking down through the first week of April.
It’s a pattern “optimized for severe thunderstorm outbreaks,” Ventrice wrote.
But around mid-April, Ventrice offered some encouraging news. “There is a glimmer of hope in the models for a relaxation,” he wrote. That “could start to temper down severe thunderstorm activity for a short-period in time.”