ORLANDO, Fla. – Despite having officially passed the historical peak, Sept. 10, of the tropical season, long-range forecast data actually indicates we’ve yet to see what the Atlantic has to offer.
As we prepare for fall and turn our attention to the holiday season, there are increasing signs that the western Caribbean and the east Atlantic may start to produce more tropical activity than August and early September have provided.
Preseason forecasts are heavily in question thanks to such lengthy periods of time occurring between tropical systems. For example, this time last year, we were watching major Hurricane Lee churning through the central Atlantic before curving north to impact the Northeast.
Lee was the 12th named storm of 2023. Currently, we have realized six named storms this season.
So, despite all the initial discussion of a potentially “historic” and “extraordinary” season, the basin seems to be frugal when producing our tropical cyclones. Overall, this is fantastic news for those in hurricane-prone areas. We can’t, however, drop our guard on the second half of the season, which runs through November 30.
A few interesting details have been shared over recent weeks to try and explain why tropical activity has been fairly scarce.
One being dry air brought on by winds flowing in from up north directly into the Atlantic, where tropical waves attempt to get their act together. The dry air causes thunderstorm activity to dissipate and does not allow the waves to bubble up into more than just an area of very ragged showers.
Another interesting piece happens to be a very warm upper-level atmosphere. Where weather is observed on our planet, meteorologists inspect what the temperature does as you rise from the surface to the highest point above us. If the temperature stays relatively uniform, storms can’t form. As a result, the usual “wave train” we see this time of year has been quiet.
Moving into the fall season we are anticipating temperatures to potentially support more thunderstorm activity over Atlantic waters.
We also see signaling for a very aggressive Madden-Julian Oscillation to move through the Atlantic west to east. The “MJO” is essentially a large area of rising motion and increased storm coverage. On a weather map, one could compare it to the size of North America. As this area moves over tropical basins, it gives a little extra leverage to tropical waves and disturbances that may be attempting to organize into a full-fledged storm.
The combo of increasing instability and the MJO has triggered models to highlight potential hot spots for us to watch toward the end of September and especially the first half of October.
Combine these two pieces with a now strengthening La Nina, and we can safely say the hurricane season is far from over.