What Does Invest 98l Mean?

If you’ve been keeping up with the tropics this week, you’ve probably heard the term “Invest 98L” at some point when hearing about the tropical wave we’re watching in the Atlantic Ocean. If you’re not familiar with what the term means, here’s a few notes to catch you up to speed.

Right off the bat, the term “invest” is nothing new.  It’s been used for years in weather circles to point out areas on the tropical weather map that require closer examination. The term “invest” is essentially just a shorter way of saying “area of investigation”.

The number attached to the term helps keep order. Invest areas are numbered from 90 to 99, and once you hit 99 the list starts over at the start at 90. Our current tropical wave to watch is Invest 98L, as it’s the 9th time this year an invest area has been monitored. Whenever the next area of interest comes along, it would be called Invest 99L.  After that, the order would go back and start over at Invest 90L.

The letter that follows the number in the term “Invest 98L” is to classify which ocean we’re talking about. Areas to watch in the Atlantic Ocean use the letter “L”. Areas to watch in the western Pacific Ocean use “W”. Regions of concern in the eastern Pacific use “E”, while in the central Pacific the letter “C” is used.

Since invest areas mark regions of tropical weather worth investigating, after an area is designated tropics forecast models begin their work analyzing and plotting out potential paths on where it may go.

The result that you’re probably familiar with when watching a TV newscast is sometimes called the “spaghetti models”. They are shown as lines originating from the probable center of the region of disturbed weather attempting to depict where it might go.

Since multiple forecast models exist, it’s not uncommon to see numerous lines. Each one is doing its best given the available data to show where the center of a possible tropical system may go.

When the lines are closely packed, a high degree of confidence can be given to that part of the forecast. In places where the lines vary widely, a lower amount of confidence can be given to a forecast at that particular stage in time.

Something important to point out is that just because something is designated as an invest area, it’s not a guarantee that it will form into a hurricane. There have been plenty of instances where invest regions are followed that amount to nothing. With this invest area, it’ll be important we monitor its progress over the next week.