Nighttime Severe Thunderstorms and Tornadoes Are Likely Tonight in the South

The Storm Prediction Center has issued a tornado watch for portions of Louisiana and Mississippi as a dangerous nocturnal severe weather outbreak gets underway. An enhanced risk for severe thunderstorms—a three out of five on the scale that measures the threat for severe weather—is in place tonight for the Mid-South. Severe weather, especially tornadoes, are extremely dangerous after dark because you can’t see and many people start tuning out the weather as they head off to bed.

The situation tonight is a classic setup for severe weather in November. A developing low-pressure system over the Midwest is dragging a cold front across the southern states. In fact, you could apply just about everything I wrote about last Wednesday’s risk for severe weather to today’s risk, just moving all the locations a bit to the north and east. Warm, unstable air ahead of the cold front will foster the development of thunderstorms, and wind shear ahead of the storm system will allow the individual thunderstorms to turn severe.

All modes of severe weather are possible, including damaging straight-line winds, large hail, and tornadoes.

The Storm Prediction Center has issued a 10% risk for significant tornadoes across much of Mississippi and central Tennessee. The black hatching indicates the area where the environment is capable of support tornadoes that could be strong or long-lived. Tornadoes are most likely in discrete (individual) thunderstorms that pop up ahead of the main lines of thunderstorms that develop along the cold front pushing into the region.

The threat for damaging winds is greatest in the line (or lines) of storms as they organize ahead of the cold front tonight. However, tornadoes are also possible in those lines of storms. Just like we saw last week a bit farther to the southwest, we could see little kinks develop along the leading edge of the lines of thunderstorms. These rotating kinks can lead to tornadoes that develop quickly, sometimes with little or no lead time before it hits.

The storms will move from west to east through the nighttime hours, reaching the Appalachian Mountains by early Tuesday morning. The line will regenerate on the eastern side of the mountains by Tuesday afternoon, bringing the risk for severe weather to parts of the southeast and Mid-Atlantic during the day tomorrow. If you haven’t voted yet, it’s a good idea to vote early so the weather doesn’t affect your ability to cast your ballot.

Severe weather is dangerous anytime, but storms pose a greater threat to life in the cold months and even more so again after dark. Many people want to see a tornado coming at them before they act. On top of the many, many reasons that’s a bad idea, the least of which is the fact that you can’t see tornadoes after dark. What’s worse is that the tornadoes in a setup like this are likely to be rain-wrapped, adding an additional shroud to the tornadoes that makes it impossible to see them even when they’re backlit by lightning.

Make sure the emergency weather alerts are activated on your phone. I know quite a few people who tried to disable them in the lead-up to last month’s nationwide test of the Emergency Alert System. There are people alive today only because they acted when the Wireless Emergency Alerts pushed a tornado warning to their smartphones. If you don’t have a smartphone or live in an area with a bad signal, keep a television or radio on when you go to sleep so you have a chance to hear warnings when they’re issued. Do not rely on tornado sirens for severe weather alerts. I know your parents and grandparents swore by them, but these systems are aging, they’re not designed to be heard indoors, and (ironically) they’re unreliable during a storm.

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