HPC, weather prediction, and how you know it's going to rain

Veteran weather forecaster Jim Witt remembers the Great Blizzard of 1947, which arrived without warning and paralyzed the northeastern United States. "They had no idea anything was going to happen," Witt recalls. Even during the storm, which eventually dropped 26.4 inches of snow on New York City, weather bureaus were predicting a light snowfall. After missing their forecasts all day, the bureaus predicted a second storm--even as the skies were clearing up, says Witt, whose protégés became senior weather scientists at the National Center for Computational Sciences, the National Hurricane Center, NASA, and AccuWeather. We've come a long way since then.