Wednesday marks the first of two extremely dangerous days of weather across the South. Ten states from Kentucky to Florida could see tornadoes, hail, damaging straight-line winds, and heavy rain as storms move through the region. The bullseye of high-impact weather will then shift to the Carolinas and Mid-Atlantic on Thursday.
Wednesday’s setup has all the hallmarks of nightmare weather. A powerful, cold low-pressure system is barreling eastward where it will smash into warm, humid air rising northward out of the Gulf of Mexico. Where opposing air masses clash, atmospheric chaos follows. And when they meet moving in different directions, that can cause storm cells to rotate and eventually spawn tornadoes.
The warning signs are all coming into place as the sun rises on Wednesday, with satellite images clearing showing the atmosphere is gearing up for an active day. The National Weather Service has issued a high-risk outlook—the highest level of alert it issues—for those states as well as a tiny corner of Arkansas that are collectively home to 2.8 million people. The agency is calling for a “significant tornado outbreak, with long-track, intense tornadoes.” Long track tornadoes are just what they sound like—tornadoes that touch down and travel for miles, leaving destruction in their wake.
Tornado risk is expected to peak Wednesday afternoon over Arkansas and Louisiana. By the evening, the risk will hit a fever pitch in Mississippi and Alabama. Overnight tornadoes are two-and-a-half times more deadly than their daytime counterparts. A comparatively small overnight tornado outbreak in Tennessee last year, for example, led to 24 deaths.
Among the cities in the area under high risk on Wednesday are Birmingham and Tuscaloosa in Alabama and Jackson, Mississippi. The latter is in the midst of a water crisis sparked by last month’s severe cold snap, and the prospect of a tornado or other forms of severe weather could only add to residents’ struggles. Beyond the high risk zone, there are also areas of moderate and enhanced risk. All told, the region in peril is home to nearly 10 million people and includes major cities like New Orleans and Memphis.
Tornadoes are far from the only thread tied to Wednesday’s storms. Damaging hail as well as straight-line winds could pummel the region. In addition, storms could produce flash flooding. In short, this is a cornucopia of the worst types of weather, and if you live anywhere in the region, you should be prepared. Disaster managers on the ground in the South are already gearing up for a busy day ahead. Alabama Gov. Kay Ivey has already declared a state of emergency. In Mississippi, covid-19 vaccination sites have been closed ahead of Wednesday’s bad weather.
Sunrise on Thursday will see renewed tornado risk over the Mid-Atlantic, Appalachia, and the Carolinas as well as parts of Georgia and Florida. Though the risk won’t be quite as high as Wednesday’s, it will cover a massive amount of people and major metro areas. The NWS forecast calls for enhanced or moderate risk to affect 11.3 million in the region stretching from Atlanta to Norfolk, Virginia.
Some research indicates that clusters of tornadoes are becoming more common as climate change heats up the planet. Of course, natural factors also play major roles in driving outbreaks. The simple fact that it’s spring, a time when cold and warm air masses are more likely to come in contact, is a determining factor here. But while science is nowhere near ready to attribute individual severe weather outbreaks to the climate crisis, it’s a reminder of the manifold risks the world needs to prepare for.
Update, 12:50 p.m. ET, March 17: The NWS has issued an even more urgent tornado risk outlook. The agency is calling for a 45% chance of tornadoes on the Alabama and Mississippi border. While that may not sound high compared to, say, a 90% chance of rain, it’s extremely rare for odds of tornadoes forming to be at that level.
That’s led the local NWS Birmingham office to issue a “particularly dangerous situation” tornado watch until 7 p.m. local time. That classification is used for just 3% of tornado watches, according to the Weather Channel. What was already a bad situation is somehow looking even worse.