The National Weather Service's New Philosophy

COLLEGE PARK, Md.—“I woke up Friday night with a dream that it had missed the peninsula,” said Bill Lapenta, the director of the National Centers for Environmental Prediction.

We sat looking at a screen that showed Hurricane Irma’s long journey across the Atlantic Ocean. Another monitor showed a live satellite feed of the cyclone, the hurricane a splotch of rainbow data, its eye coming closer and closer to the Florida mainland. Across the room, Jim Cantore shouted through the television that Irma was about to make landfall.

Lapenta had been thinking about Hurricane Irma for days. No element of the storm’s forecast, he told me Sunday, was more important than its projected last-minute turn in the Florida Strait. For more than a week, meteorologists had insisted that the storm would travel west along the Cuban shore before suddenly shifting north toward the Florida peninsula. If it failed to pivot, it would sail harmlessly into the Gulf of Mexico. Six million people had been evacuated on the basis of this alleged turn. Florida