There is a tropical system passing over South and Central Florida this weekend (23-25 August 2019). Not very unusual – Florida gets systems like this just about weekly during the summer! But this one does show some signs of organization, and once it moves back out to sea might cross the threshold to become a system officially tracked by the US National Hurricane Center. Before they are “officially” tracked (in other words, with formal 6 hourly public advisories), these systems are called “Investigation Areas” or INVEST areas. It’s not too likely this thing will be strong enough over land to cause problems, and any strengthening shouldn’t happen until after it moves away from the US or Islands.
Right now, this system is called “AL982019”. What does that mean? All tropical systems are given tracking codes in the form BBNNYYYY where BB is the basin, NN is a number code, YYYY is the year. The basin codes are pretty straightforward: AL is the Atlantic, EP is the East Pacific (off of Mexico), CP is the Central Pacific (Hawai’i), WP is the West Pacific (Asia), IO the Indian Ocean, and SH the Southern Hemisphere. The number codes are a little tricky. Numbers 90 and above are reserved for INVEST areas and are reused during the season. This bears repeating:
Be careful searching on teh intertubs for invest areas by the codes:
they are re-used during the season!
If the system meets the criteria to become a system with advisories, it is given a “permanent” code, the next in line starting at 01 for each year (January 1st in the Northern Hemisphere. In the Southern Hemisphere, the year starts September 1st of the previous year, so a tropical storm forming off of Australia in November this year might have the code SH032020! ). Note this is different from the name of the storm. The criteria for a storm being “tropical” and being “named” are different! So AL03 may not be the “C” named stormed. In fact, the presently active Chantal is AL04 because there was a previous system that was organized enough to start advisories, but did not meet the criteria to become a “named” storm.
Here’s the track map as of 7am this morning. Some models kill it off, some spin it up after it moves off shore into the Atlantic. NHC is saying 30% chance of it meeting the criteria to be a minimal tropical system in the next two days, and 60% in the next 5. Again, even if it does, this system is not likely to have any significant impacts.