After decades of silently shouting at the top of its lungs,the National Weather Service recently announced that it’s going to stop publishing its forecasts and weather warnings in ALL CAPS. Beginning May 11, for the first time ever, we’ll start seeing mixed-case letters.
The weather service’s caps-lock habit didn’t happen entirely by choice. Old equipment left over from early weather service days of the late 1800s could only handle capital letters. Unfortunately, people have since learned to recognize those capital letters AS YELLING.
It’s taken a long time for the weather service (and its customers) to update all their hardware and software, but now they’re finally ready to enter the 20th Century. . . . In the case of the weather service’s all-caps type, it’s the font version of the boy who cried wolf. Using ALL CAPS for everything — from severe hurricanes to a slight chance of showers — means that EVERYTHING LOOKS THE SAME AND EVERYTHING LOOKS IMPORTANT. Once people realize that most of the time it’s not, they may become desensitized to warnings. When nothing stands out, people are likely to miss real emergencies.
Now that the weather service can use ALL CAPS sparingly — as a tool to highlight real danger — the public is more likely to pay attention.
“We realized we could still use ALL CAPS within products to add emphasis, such as ‘TORNADO WARNING. TAKE COVER NOW!’" said Art Thomas, the weather service meteorologist in charge of the project. “We hope that using all caps for emphasis will get people’s attention when it matters and encourage people to take action to protect their safety.”
Samples of both ALL CAPS and mixed case area forecasts from the weather service. Source: NOAA.
I've read elsewhere that the convention that ALL CAPS reads as yelling dates to the 17th century.