It’s been an unusually quiet stretch during what is traditionally one of the busier parts of the hurricane season.
The Atlantic hasn’t produced a named storm since Ernesto, which formed way back on Aug. 12.
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As Dr. Phil Klotzbach, a senior research scientist at Colorado State University, heads up the gold standard of seasonal outlooks posted to social media this morning, this is the first time since 1968 the Atlantic hasn’t notched any new formations between Aug. 12 and Sept. 3.
Not to mention, the disturbances with any development potential since Ernesto have largely underperformed. We see those struggles in the system we’re following through the Caribbean on Tuesday.
So is it time to raise the white flag and surrender to/celebrate what appears to be a big seasonal bust?
What the past tells us
There’s no denying the past few weeks have been unusual and unexpected, but a funky period sandwiched in the ramp-up period to the traditional seasonal peak isn’t without precedent.
Consider 1961, which saw Category 2 Hurricane Anna in July, then went 46 days before Betsy formed in September, a Category 4 hurricane immediately followed by Category 4 Carla and Category 5 Esther.
It was a year scraping the bottom of the ACE barrel (Accumulated Cyclone Energy or ACE is used as a scorecard for seasonal hurricane activity) at the turn of September that even to this day remains a top 10 ACE producer.
More recently, 2022 went an astounding 61 days between Colin on July 1 and Danielle on Sept. 1, a season with a third the activity through Sept. 2 as this season, but which ended above average, with a catastrophic hurricane hit (Ian) and the latest hurricane strike on record for the Florida peninsula (Nicole).
Why we shouldn’t bet against the back part of the hurricane season
The Main Development Region of the tropical Atlantic is egregiously warm – amazingly still rivaling 2024′s unprecedented levels – and vertical wind shear has been well below average across the bellwether Caribbean.
These are two important factors – the two biggest factors identified by researchers – for hurricane season activity but not the only factors at play.
Seasonal forecasts have busted before, most famously in 2013 which saw the lowest activity in 30 years despite calls for above-average hurricane activity.
Could 2024 become another 2013? While it’s certainly possible the seasonal outlooks get it wrong this year, the issues we’ve identified so far shouldn’t be a showstopper.
If part of the issue has been a northward displaced monsoon trough – a breeding ground for tropical saplings that’s lately become entangled in dry and dusty air – it should naturally correct as the monsoon trough shifts southward this month.
As we’ve discussed in previous newsletters the Central American Gyre also becomes a bigger player again in September and October, which would presumably pick up any slack left from anemic tropical waves.
Lately, there’s also been chatter of very warm upper levels in the troposphere (at around 50,000 or 60,000 feet) – a byproduct of global warming – that could be making the Atlantic more stable than normal and capping thunderstorm growth despite record-warm sea surface temperatures.
If this is indeed the case, the upper levels naturally cool during the fall, and at a much faster rate than the ocean, so the cooling in the air above would naturally make the atmosphere less stable for the back part of the hurricane season.
We’ve also written that the emerging La Niña in the eastern Pacific gives credence to a backloaded hurricane season, something researchers have shown during previous La Niña episodes.
With 65% of tropical activity typically happening after Sept. 3, including some of the strongest hurricanes on record, and without a smoking gun to explain why the struggles should persist, it’s premature to call the season a bust, especially after a catastrophic Category 5 hurricane and two U.S. hurricane landfalls.
None of us will complain if the current struggles continue but we also know better than to presume they will.
Caribbean disturbance struggles to organize
The disturbance we’ve been tracking since last week is now moving south of Haiti and the Dominican Republic in the central Caribbean. Storminess has waxed and waned around the tropical wave, but it’s so far been unable to maintain persistent thunderstorm activity.
While the National Hurricane Center has a medium chance for development by this weekend as it approaches Central America, forecast models are lukewarm on its prospects.
Regardless, heavy rainfall will be the upshot for parts of Belize, Honduras, Guatemala, and southern Mexico into early next week as the system moves westward.
The system poses no threat to South Florida.
Two Atlantic disturbances staying far away
We’re also monitoring two disturbances in the central and eastern Atlantic. The tropical wave in the eastern Atlantic that’s currently affecting the Cabo Verde Islands off Africa has a modest chance of slow development into next week.
Meanwhile, a spunky tropical wave in the central Atlantic between Africa and the Caribbean could try to organize in the days ahead.
Both systems will stay well away from the islands and the mainland U.S. into next week.
