With Hurricane Gabrielle having drifted out to sea as a downgraded Category 2 storm in the North Atlantic, all eyes have shifted to the pair of tropical systems in the southwest Atlantic. The stronger of the two — formerly Invest 93L — eventually strengthened into Tropical Storm Humberto Wednesday afternoon, while less than a thousand miles to the west is Invest 94L, which is very close to Puerto Rico.
Invest 94L also has a good chance, 80 percent or higher, of developing into a tropical depression or tropical storm within the next several days. As of now, both Humberto and 94L are moving in somewhat different directions, with Humberto tracking more to the northwest. However, that may not be the case for very long since Invest 94L could curve quickly north. There is considerable uncertainty about what will unfold over the next two days and whether either one will ultimately be a land threat.
As of now, it appears that these two storms are far enough apart to avoid any interaction, but there is the chance that one may attempt to merge with the other, which would throw any forecasting at this point out the window. This type of merging is called the Fujiwhara Effect, where two tropical systems rotate around a common center, with one storm eventually absorbing the other. The chances of this happening are low, but not impossible. What we do know is that the western storm, Invest 94L, has a more hostile environment to work through.
Here are the latest maps on what Humberto, Hurricane Gabrielle, and the future Tropical Storm Imelda (Invest 94L) are up to in the tropics:
Right now, there is a divide between the models, and naturally so, as hot sea surface temperatures, the fuel for hurricane development, try to overcome moderate wind shear. The Euro and Google’s AI models suggest that the western system may make landfall on the Carolinas, while Humberto curves out to sea. Of course, these forecast tracks will change on a daily basis over the next few days.
Humberto could influence the western storm, directing it southward. Look at how the Euro model, below, shows Humberto and Invest 94L as they move closer to the East Coast, with Invest 94L to the west, pulling back to the south.
This hurricane season is reawakening and showing signs of life after a historic lull from late August through the peak of the season, Sept. 10, when no named storms were active.
Ken Mahan can be reached at ken.mahan@globe.com. Follow him on Instagram @kenmahantheweatherman.
I love how the article talks about the Fujiwhara Effect like its a high-stakes game of atmospheric tag. The maps look like a chaotic game of connect-the-dots, and Im on the edge of my seat waiting for the models to contradict each other again. Its like watching my cat chase its own tail, but with way more data points!