KANSAS CITY, Mo. - The National Weather Service office in Pleasant Hill, Mo., implemented two changes for warning people about severe weather more than a year ago, but both have gone mostly unused. That's because of last summer's mostly dry weather pattern.
A new "dual polarization" radar system allows the NWS to more accurately decipher precipitation. In the past, meteorologists had a more difficult time telling the difference between rain and hail.
Dual polarization shows the full shape of what's falling from the sky. NWS meteorologist Andy Bailey said it makes for more precise areas to warn.
"Ideally, we'd like to only warn people when they need to know about the storm," Bailey said. "If we over-warn people, it kind of leads to a 'cry wolf' syndrome and people may just start to ignore the warnings."
Once the NWS issues a warning for a severe thunderstorm or tornado, the robotic voice delivering the message is the same, but the message has changed.
The NWS calls the new system "impact-based warnings," which not only warn listeners about weather conditions, but also the damage and danger that can accompany the storms.
For example, the script of a tornado warning might tell people they could be killed if they're not underground; that flying debris will be deadly to people and animals; that complete destruction of neighborhoods is possible.
The warnings are more ominous, but Bailey said they're necessary and life-saving. He said they're especially relevant this season because last year, only two tornadoes struck the NWS Pleasant Hill region. In a normal year, the area measures between 10 and 14 twisters.
"Probably our biggest fear is that people are a little complacent. Maybe they've got a little swagger about them ... 'Yeah, I'm from the Midwest, I know what to do,'" Bailey said.
The impact-based warnings actually rolled out last year in four NWS regions, including Kansas City. This year, 38 Midwest NWS offices are using the system.