An Invest (short for Investigation), also called an area of interest, is a designated area of disturbed weather in the tropics investigated by the National Hurricane Center (NHC). Once the National Hurricane Center declares an Investigation Area, spaghetti models are run on the system to project the future track possibilities, like the ones shown in the image, as well as the potential future intensity. That said, the “Invest” assignment does not correspond to how likely a system may develop into a tropical depression or storm!
The term Invest is followed by the numbers 90 through 99 and either the letter “L” for the Atlantic basin systems or “E” for the eastern Pacific systems. These full labels in the Atlantic would be displayed as Invest 90L, Invest 91L, etc. In the eastern Pacific, you would see Invest 90E, Invest 91E, etc. Once the end of the list is reached with either Invest 99L in the Atlantic or Invest 99E in the eastern Pacific, it starts back over again with Invest 90L or Invest 90E. The process can be repeated for as many times as needed. Many times in discussions these designations will be shortened to 90L, 91L, and so forth.
This naming system gives forecasters a way of keeping track of weather systems on which they want to begin gathering more detailed information. Also when we have multiple tropical disturbances out there this system also makes it easier for meteorologists to communicate what invest the are talking about!
I hope this information helps you understand now when people during Hurricane Season mention the word INVEST! As always Track The Tropics is the #1 source to track the tropics 24/7 and keep up to date on any threats to land during the Atlantic Hurricane Season! Be sure to visit my home page and the tons of other information I have on the site.