Weather Words: Invest

Every named tropical system has to start somewhere, and for many, the early days before a name is even given, it starts as an “invest.” Short for “investigation,” an invest is a designated zone in the ocean that the National Hurricane Center (NHC) or other weather agencies are watching for potential tropical development. Once a cluster of thunderstorms shows signs of organization or poses a long-range threat to land or shipping routes, it can be labeled as an invest and assigned a number 90-99 and either the letter L or E (like Invest 92L in the Atlantic or 99E in the eastern Pacific).

Assigning an invest doesn’t mean a storm will form, but it does signal a shift in attention. It allows computer models to start running dedicated forecasts on that specific area and triggers more frequent satellite analysis and, in some cases, reconnaissance flights – when the hurricane hunters are called in to fly through the storm and collect data. It’s basically the meteorological world’s way of saying, “Let’s keep a close eye on this one.”

While not all invests will become named storms, many are the early chapters of hurricanes that will later dominate the news. For forecasters and weather watchers alike, seeing a new invest pop up is a reminder that hurricane season is here, and preparation may be needed down the road.

Jennifer Gray is a weather and climate writer for weather.com. She has been covering some of the world’s biggest weather and climate stories for the last two decades.