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Posted at 03:15 PM ET, 05/02/2011

The problematic confusion about difference between tornado watches and warnings

During the tornado outbreak last Wednesday and Thursday that spun up 19 twisters in the region, my colleague and Metro section columnist John Kelly tweeted out:

“Am I the only person who can’t tell a tornado WATCH from a tornado WARNING? Hard to remember the difference. They need better names.”

Am I the only person who can't tell a tornado WATCH from a tornado WARNING? Hard to remember the difference. They need better names.less than a minute ago via web Favorite Retweet Reply

Now Kelly is one smart dude, who has even written about weather over the years. For example, he recently reported on the demise of the Verizon Weather Line and two years ago penned a column with the sage words you might not like “wintry mix,” but you must respect it.

But seriously, if someone like Kelly has to stop and think about what the difference between watch and warning is, that’s a serious issue the weather communication business must confront. The failure to recognize the meaning of a warning during a dangerous weather event could (and no doubt does) result in the loss of life and/or property.

And Kelly is hardly the only one who’s confused. A study conducted at the University of Oklahoma by Scott Powell and Dan O’Hair tested the weather knowledge of 762 Texans, Oklahomans and Californian. It found 36 percent of respondents did not know the difference between a severe weather watch and severe weather warning. Of the Californians surveyed, 50 percent didn’t know the difference compared to around 30 percent of the more storm prone Oklahomans and Texans.

Granted, if you read this blog, you probably know the difference between these terms. But to make this crystal clear, here is how the National Weather Service defines them:

A watch is used when the risk of a hazardous weather or hydrologic event has increased significantly, but its occurrence, location, and/or timing is still uncertain. It is intended to provide enough lead time so that those who need to set their plans in motion can do so.

A warning is issued when a hazardous weather or hydrologic event is occurring, is imminent, or has a very high possibility of occurring. A warning is used for conditions posing a threat to life or property.

Or to put it another way, a tornado watch means: conditions are favorable for some tornadoes to form but no guarantee - be vigilant; a warning means: a tornado has been detected by radar and/or spotted - take cover NOW - a tornado is likely (but not definitely) near you.

This seems pretty straight forward, but for those who only pay to attention to weather once in a great while, the terms may not be sufficiently self-explanatory and distinct to tell the story - especially out of context.

Case in point: the Powell and O’Hair study found some survey respondents completely misinterpreted the meaning of a watch:

“In many cases, participants answer that a watch supersedes a warning thinking that a watch involves a visual confirmation,” it said.

It also discovered that when some people hear the term warning, they assume severe weather is “definite” whereas, in actuality, the a storm or tornado may only affect some small portion of the warning area:

“During a tornado warning, even if a tornado occurs, it will only affect a small swath of the entire warning polygon,” it said.

(Also, the failure for some warnings to verify raises the whole specter of the loss in trust in warnings due to false alarms - which is a related, but separate issue.)

To overcome the watch vs. warning confusion, Powell and O’Hair and others have advocated better education. John Kelly thinks we need “better names.”

What do you think?

By  |  03:15 PM ET, 05/02/2011

Categories:  Thunderstorms, Latest

 
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