A better outlook: SPC revises its severe categories

In 2014, The Storm Prediction Center (SPC) announced that they are making some changes to the way the agency handles its severe weather risk outlook. They made the changes in order to better reflect the range of severe weather possibilities. I know from first-hand experience that this change will be very helpful!

The biggest miscommunication I ever had at work can be traced to an SPC outlook. I was 25 years old, still fairly new to the TV weather business, and working in Harrisburg, PA. I was sitting in the morning meeting with our newscast producers, reporters, and managers. When the boss asked if I had anything to contribute, I told them, "The Storm Prediction Center has our area in the slight risk category for severe thunderstorms this afternoon and evening". The news was largely brushed off, and I was sent out to cover a non-weather-related story for our evening newscast. Later that afternoon, as severe thunderstorms developed, it became clear to my boss that I should not have been sent out on assignment that day, and instead, I should have been helping the chief meteorologist with severe weather coverage. My boss said to me, "But Erica, you said it was just a slight risk!"


This is an example of bad communication on a couple of fronts. Still a newbie to TV weather, I didn't understand that I had to take the weather message coming from the SPC and give it a sense of urgency that my non-meteorologist colleagues would understand. But in addition, since I delivered the message so directly, it pointed something out to me that should've been glaringly obvious: the word "slight" does not convey any sense of urgency to the general public.

Now, after years of analysis and review, the SPC has revised its severe categories. The new categories are: MARGINAL; SLIGHT; ENHANCED; MODERATE; and HIGH. Each category is associated with the probability of severe weather elements taking place (wind, hail, and/or tornadoes). Perhaps you have already heard these new terms in use or read about them in our forecast discussion right here on wusa9.com.

The 2 most obvious changes are that there is an additional category now (ENHANCED), and that the old sub-category of "SEE TEXT" is being replaced by MARGINAL. But, all across the board, the criteria for each category have been re-examined, in an effort to make sure that the categories convey the right message for severe weather probability.

What does that mean for you and me? Personally, I think the word "Marginal" is more appropriate than a broad "See Text" category, which directs you to a fairly technical discussion about the day's severe weather risk. "See text" could sound menacing or it could sound benign, depending on your perspective. I think "marginal" is a much better word to convey the idea that, within this area, severe weather is possible, but not likely.

I also like the additional category of "Enhanced". As it stands today, the "Slight Risk" category includes a pretty broad range of potential severe events. For instance, a SLGT for Missouri can include as much as 10% risk for a significant tornado! The new categorical division better reflects what happens in a severe weather environment; namely, that life-threatening tornadoes are much more likely in events that also contain large hail. Here's a chart of the new SPC outlooks:

Of course, none of this new material actually solves the issue that I experienced, sitting in that newsroom in Harrisburg several years ago. A "Slight Risk" designation still means that there's a pretty good chance you'll have severe weather in that region. The 25-year-old version of me still would have told the rest of the newsroom that there was a slight risk for severe weather that day. But, perhaps this is just a starting point, and more changes are in the works. In any case, I think it's a move in the right direction!

Want more info? Check out this article by the Capital Weather Gang!


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