"We can't do this with every event," said the prediction center's Ken Miller, noting that many storm systems are not as easy to predict whether they will be a potential threat to life and property.
Miller said he was pleased the warnings were heeded.
"We measure our success by how the public reacts," he said. "Do they take precautions seriously and act on them?"
"People become used to those warnings. That is a dangerous complacency," Duncan said. "We need to break through the clutter of everyday noise to get people's attention."
The warnings had Larry Hill's attention. The 72-year-old sifted Sunday through glass and debris of his home. Hours earlier, Hill had barricaded himself in a closet as a tornado ripped the roof off his home in the southwest Iowa town of Thurman. He kept a close ear on their television as Saturday night approached, and had bought extra groceries the night before.
"We'd been on the lookout for it for three days," he said. "... We were as ready as we could have been."
A National Weather Service official said a "month's worth" of tornados were spotted Sunday in Kansas. About 100 homes were damaged in a Wichita mobile home, but no serious injuries or fatalities were reported.