Have you heard us say we are starting to track an Invest (insert number/letter here) in the Atlantic, Gulf, or Caribbean? 

Invest is short for investigation. The National Hurricane Center, as well as other tropical cyclone forecasting offices worldwide, use Invest when an area is under investigation for tropical formation. Invest labeling does not correspond to how likely the area may form into a tropical depression or tropical storm.

Once an area is assigned as an Invest, special numerical future projections or models are begun to analyze whether it has a potential to become a tropical depression or a tropical storm. Future intensity and track is also projected. Sometimes, they form into full-blown hurricanes, and other times they might just fizzle out and disappear entirely.

Once an area is marked as an Invest, it is also assigned a number and letter. The numbers 90 to 99 are used for Invests, starting with 90 and continuing to 99 as long as there are more Invests. Once 99 is reached, we rinse and repeat, beginning with 90. 

So why the letter such as Invest 91-L or -E? An Invest with a different letter designation corresponds with a different ocean, part of an ocean or body of water.

  • L: Atlantic Ocean, Gulf Of Mexico, Caribbean Sea
  • E: Eastern Pacific Ocean
  • C: Central Pacific Ocean
  • W: West Pacific
  • S: Near Australia
  • P: Near Australia
  • A: Arabian Sea
  • B: Bay Of Bengal

If the Invest forms into a tropical storm, it will get the next name on the corresponding tropical names list and the Invest label is dropped. The above nomenclature, or naming system, makes it easier for identification.