ORLANDO, Fla. – Does it still feel like it’s hurricane season for you? Because for me, not so much. It’s been abnormally quiet, and even quieter when compared to how bizarre the last hurricane season treated us. At this point, if you were to rewind 365 days, Hurricane Francine had just made landfall in Louisiana, and Floridians were bracing for what would become a major Hurricane Helene.
This year, we’re not quite at that point. Not even close, actually. We do have Invest 92L on the board, expected to develop into our next named system within the next day or two. This is a far healthier and larger tropical feature than the prior 91L was.
Confidence is much greater this go around that Gabrielle will soon be entering the Atlantic fray.
We’ve also seen another tropical wave moving off the west shores of Africa, highlighted by the National Hurricane Center. For the first time in a LONG time, the homepage of NHC has two overlapping blobs of color; one red and one yellow.
Even then, this is still well below the usual sort of action we’d see across the tropics.
While this is amazing news, we can almost forget hurricane season when we’re usually most into the weeds with tropical development, what can we expect for the rest of September? I want to break that all down for you carefully this morning.
There are a number of factors working against the tropical Atlantic this go around, even if we are getting a friendly nudge by climatology based on the time of year.
We’ve had several bouts of dry air being blasted into the eastern Atlantic, where we’d usually find our tropical waves headed into the Main Development Region. If you’re unfamiliar with the MDR, for short, it’s the extension of the Atlantic between the Lesser Antilles out to the coastline of Africa.
These nasty dumps of dry air continue to erase each of these individual waves just as they make their way offshore and westward into the Atlantic.
A side effect of this barrage of continuous dry air plunges is things called Tropical Upper Tropospheric Troughs. You can call them TUTTs.
You’re probably familiar with the troughs of cooler air that come down from up north and provide Florida with occasional relief from the summertime conditions we usually feel in one way, shape, or form year-round.
These troughs over the ocean are incredibly similar to those we see that will extend southwestward into the Tropical Atlantic during the hurricane season. Tropical waves, tropical systems, hurricanes — they do not like cool, dry air. They also despise temperature gradients, which these TUTTs will bring down with them.
So, while we’ve had some fairly healthy and robust waves meandering westward off Africa, they’ve been met with the harshest of conditions, where none of them last more than a day or two.
Will that last for the rest of the month?
In short, more than likely. We’ll probably continue to see repetitive pushes of dry, stable air from up north into the tropics. The question is, will every wave end up erased, or will some actually survive and pull through to get going?
The rest of this month into October could look a little like a one-on, one-off type of scheme. For example, the tropical wave currently highlighted behind our current invest will likely fall victim to the dry air and the sinking motions provided by it. Where there’s sinking, there’s stability, and with stability, you usually see crystal clear weather.
Again, anything tropical just doesn’t like that.
There’s another tropical wave behind the one highlighted presently (I know, wave after wave after wave, which wave?). This one seems to win the lottery in terms of general timing to avoid one blast of dry ahead of it and another back behind it.
We’ll see if NHC pulls the trigger on that one over the coming days.
So if you’ve stuck with me to the end of this discussion, despite the hostility we’re still seeing across the Atlantic, water temperatures are back to above the average. We also have the Madden Julian Oscillation preparing to cycle through.
That phenomenon, the MJO, has also been a tricky sub-seasonal feature we’ve been watching carefully. It seems we’re seeing a similar issue to last year, where it gets stuck over the Central and Eastern Pacific, struggling to move as far east as the Atlantic side of things. That should start to subside a bit, and we get rocking for the second half of September.
If things line up appropriately, we could very easily realize 2-5 named storms before the end of the month. Right now, there are no imminent or even mid-range threats to Central Florida. I’ll have the western Caribbean and the Southern Gulf under a microscope for everyone. This is usually the time of the season when the good ol’ Central American Gyre, or CAG, tends to resurrect.