These types of tornadoes are ones that consistently remain on the ground for an extended period of time, unlike a typical one that could be on the ground for just minutes.
The system that will be responsible for these strong storms is currently impacting the Southwest, and will make its trek through the Rocky Mountains and eject into the Plains by midweek, allowing for an atmospheric set-up conducive for dangerous storms to form.
“We’ve got increasingly warm and humid air over the Gulf of Mexico that will lift rapidly northward — those large scale conditions are quite favorable for severe storms. We think some of the smaller details that we often see on higher end days, especially with significant tornado potential, will also be in place,” said Bill Bunting, chief of forecast operations at the SPC.
“This is a very strong system that we’ve been tracking the potential for severe storms as it develops and moves off to the northeast, from the Plains into the Ohio Valley,” meteorologist Jason Holmes at the NWS office in Birmingham, Alabama told CNN.
Timing out the storms
The threat for thunderstorms begins as early as Tuesday evening for much of Kansas, Oklahoma and northeastern and central Texas.
The highest risk, however, will likely be during the overnight hours of Tuesday and continuing into Wednesday morning. An isolated tornado will be possible, especially in central Oklahoma, but the main risks will be large hail and damaging winds.
There will also be a separate risk for a few strong storms across the South during the day Tuesday, including parts of Mississippi, Alabama and Georgia.
“Our real day of focus right now is Wednesday. We could see a fairly widespread severe weather threat and potentially some high-end severe thunderstorms,” said Bunting.
Wednesday into Wednesday night is forecast to be the most active day in terms of severe thunderstorms this week. There is currently a “Moderate Risk” for severe weather across five states in the South, according to the SPC. A “Moderate Risk” is a level 4 out of 5 in terms of its potential severity. This includes Arkansas, Louisiana, Mississippi, Alabama and Tennessee.
The SPC said a “Moderate Risk” means “widespread severe storms are likely,” and all threats are possible in Wednesday’s set-up — tornadoes, large hail of at least golf ball size, and intense winds of at least 58 mph.
The ingredients for severe weather are looking so daunting that SPC is warning that an upgrade to a rare “High Risk” may be needed for Wednesday. High risk days are not used lightly — on average only occurring once or twice per year. In fact, there were no “High Risk” days in 2020. The last one was in May of 2019.
A morning round of showers and thunderstorms is currently forecast to move through parts of the Gulf Coast states. A few of these storms may be severe, but the main threat ramps up in the afternoon and continuing into Wednesday night.
During the afternoon hours, some of the states, especially in the “Moderate” or “Enhanced” risks, could see supercell thunderstorms develop. These types of storms are discrete, individual storms that are known for producing tornadoes. Not all of these storms will produce tornadoes, but given the favorable environment for tornadoes, it will be possible with some of them.
There will then be a final line of storms along the cold front ramping up in the evening near the Mississippi River and tracking east through these southern states. The storms along this front will need to be monitored for tornadoes, damaging winds and large hail.
“This (overnight) wave of severe storms will likely have the higher potential for stronger long track tornadoes,” according to the NWS office in Birmingham.
There could be “potentially a few waves of severe weather, starting in the morning, then during the middle of the day, and then later in the evening as the cold front comes in,” said Holmes when discussing central Alabama’s forecast, a region currently in that ‘Moderate Risk.’
By Thursday, the risk for strong to severe thunderstorms will shift toward the US East Coast. The region from central Florida through central Virginia is currently being monitored by the SPC for this risk. Some areas are currently in a level 3 out of 5, “Enhanced Risk,” according to the Storm Prediction Center. At this time, the specific timing and threats of the storms are unknown.
Severe storms typical for South
Severe thunderstorms are not unusual for this part of the country and during this time of the year. Historically, strong tornadoes in mid-March have been most prevalent in northern Mississippi and Alabama, which aligns closely with this week’s forecast storms.
“The details will play a significant role in just how bad things get and where the storms strike. I think what’s important is to know that it’s a typical early season, southeast US severe weather setup in the sense that storms will be fast-moving and they will continue after dark,” said Bunting.
“One dangerous aspect of tornadoes in the South is that they can occur in the middle of the night when people are sleeping unlike Tornado Alley storms that typically become less severe after sunset,” said CNN meteorologist Chad Myers.
“It’s really important to heed the warning and not wait until you have visual confirmation (of the storm),” Bunting said. “This is the time for folks to have a plan in multiple ways to get the warnings.”
This includes setting weather alert notifications on your phone. Many weather applications offer alerts based on your location, but your device also allows for you to turn on notifications for tornado warnings in its settings.