Into the Raging Sea: Thirty-Three Mariners, One Megastorm, and the Sinking of El Faro

by Rachel Slade

The BVS forecasts were even less accurate because they lagged several hours behind the NHC’s forecasts. By the time the captain downloaded them, they were based on data more than twelve hours old. Here’s why: NHC meteorologists use dropsondes, ship-reporting, and satellite data to collect raw data from land and sea. They run this mountain of data through dozens of computer models that then produce a range of possible hurricane paths and intensities. The meteorologists analyze these models, toss out anomalies, and generate a forecast. This whole process takes four hours. The BVS programmers spend an additional five hours plugging the NHC forecast into their own system before issuing their report. As a result, BVS’s forecasts are based on raw data recorded more than nine hours prior, often longer. The company that produces BVS doesn’t want to advertise that fact. Buried on page 101 of the BVS-7 manual, it says: “The forecast model run and data preparation time is approximately 9 hours.” That’s the only tip-off to users that BVS’s models weren’t fresh.