HOUSTON—Jeffry Evans’ mobile phone rang shortly before 3am, local time, instantly waking him from a deep slumber.

Not good, he instinctively knew.

The Houston meteorologist had crashed late on Monday, August 24. Before hitting the mattress around midnight, he left instructions to be awakened if the forecast for Hurricane Laura took a turn for the worse. And now it had. By early Tuesday, the overnight model guidance indicated a high probability the storm may take a more westerly track across the Gulf of Mexico and strike the fourth largest US city.