You hear this all the time now from local and national media sources, “a tornado outbreak is expected”, and often times this is proclaimed a week in advance! Every time there is a chance for a tornado this phrase is thrown around haphazardly and without merit. The truth is, this statement has lost all of its original meaning and is mostly used now in an effort to get ratings and people talking about the entity that proclaimed it with social media shares. This causes excitement, fear, scrambling of outdoor plans, etc. And guess what, in the majority of cases, none of that is warranted.
So what constitutes a real “tornado outbreak”? Is it one tornado, two, five, or even ten? Turns out, it’s all relative. It can mean different things to different people compared to the historical record for a certain area. For example, if an area that never sees any tornadoes suddenly gets 4 during one storm event, then some may consider that an outbreak. Scientists can’t decide either what constitutes an outbreak. Several research papers have attempted to categorize a numbering system from minor to major and factor in things like EF intensity and death counts. Although some feel that 6 to 10 tornadoes is a good starting point, others believe that more than 12 is where to start. This number can reach into the hundreds for a 24 hour period. So when news or weather people use this phrase, they better be predicting a bare minimum of 6 tornadoes to remain ethical in what they say. Even if you can visualize a storm system setup producing supercells, you have to realize that very few of them will produce tornadoes. Producing a tornado is not easy. A storm has to have a multitude of ingredients and just one thing missing can negate the entire threat. The atmosphere has to be set up perfectly for this to occur. On average, a major outbreak occurs only 1.6 days per year somewhere across the country.
One note to point out is that in a true outbreak there may be too many tornadoes to cover live at one time. Instead of a meteorologist spending several minutes covering a storm and giving you details about it and which streets it is crossing, that storm may get only seconds, or in some cases no coverage at all, especially if a tornado is doing damage in a large metropolitan area. Thankfully, these types of events are extremely rare and for good reason. Should that occur, look to other resources to get the information you need, such as my free weather app, ATsWeatherToGo which predicts tornadoes before they develop giving you more time to prepare.
So the next time you hear the phrase, “tornado outbreak” days before a supposed event, take it with a grain of salt. Understand that the forecasting entity thinks there will be tornadoes that day. However, keep in mind that no severe weather setup is ever truly certain, especially beyond 24 hours out. The Storm Prediction Center waits until that 24 hour window before they even give tornado probabilities for this very reason. I’m not perfect in my forecasting either and in a few of the events I thought would produce multiple tornadoes, there was little to no activity. That goes to show you we still have a long way to go at understanding the atmosphere completely and what it takes to produce an “outbreak”. Keep in mind that historically, scientists classified past events as tornado outbreaks. We have never before called future events tornado outbreaks, until now. That’s a big distinction, and one not to miss. So don’t panic, don’t worry, just pay attention to the forecast and have an alternate plan in place should a severe weather event unfold as predicted. Whether it’s 24 hours away or a week away.