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thunderstorms

Making a better severe storm warning

Of interest.

We’ve all heard them – the blaring alerts that activate our cellphones or television when a severe weather warning is issued.

Perhaps our favorite weather app sent us a push notification, or we saw a television meteorologist pointing at vibrant boxes on a weather map. Whatever the medium, weather warnings have a way of finding us, especially whenever a severe thunderstorm is close by. Now, those warnings, specifically the way in which they’re generated, are in the process of getting a makeover.

Severe weather warnings are issued for individual thunderstorms; before 2007, entire counties would be alerted at once. Over the years, weather warnings have become more targeted – but one warning can still cover an expansive area. Moreover, conditions can vary wildly even within the region enclosed by a single warning.

Now, the National Weather Service is hoping to change that.

Kodi Berry leads the program that’s updating warnings at the National Severe Storms Laboratory (NSSL) in Norman, Oklahoma. The Forecasting a Continuum of Environmental Threats program, or FACETs, is an endeavor the National Weather Service is pursuing to communicate the hazards posed by severe thunderstorms on a hyperlocal level.

Berry says the goal is provide a more continuous flow of information for those who need it the most.

According to the National Severe Storm’s Laboratory, FACETs aims to improve weather watches and warnings to provide “detailed hazard information through the use of ‘threat grids’ that are monitored and adjusted as new information becomes available.”

Typical weather warnings are issued in the form of polygons digitally drawn on a map. If you’re within the polygon, you’re alerted and urged to take action – such as seeking shelter. But just a stone’s throw away, a neighboring home outside the polygon may not be given any special instructions. The current state of weather warnings is binary, akin to a “yes” or “no” to severe weather.

Berry’s team is hoping to improve that by creating a product that reflects the gray area in between. They are experimenting with displaying probabilities to reflect the range of possible outcomes in a rapidly-evolving severe weather event.

“There has been a lot of social science research that shows that, given probabilistic information, people make better decisions,” Berry said. “If we appropriately define these probabilities and what they mean, people can use them to make better decisions.”

See here for more on the NSSL, and here for more on FACETs. I like the idea overall and agree that more precise information that goes beyond the “threat/no threeat” binary makes sense, but I’m not so sure people make better decisions when given probabilistic information. There’s also a lot of research showing that people are not at all good at understanding risk levels, and at least in a political context it’s common to see people round down small-but-not-that-small probability events to “zero”, or the converse to “one”. I’m a fan of more and better data and so I approve of the idea, I just think it’s likely that how this data is presented and explained to the public will need to be refined a couple of times.