Seasonal hurricane commentary is beginning to buzz: What we actually know right now

One-sentence summary

With early hurricane season commentary beginning to emerge, we take a look at what is known here in late February.

Tropical aggression

Yesterday, AccuWeather, the private forecasting company from State College, PA published an article expressing concern for the upcoming hurricane season, using words like “super charged” and “blockbuster.” I’m not writing today to dunk on AccuWeather. I personally know a number of folks that work there, several of whom I would consider friends of mine. But I want folks to understand both the realities and limitations of hurricane forecasting in February.

About a month ago, we posted an article in which we shared some commentary about the upcoming hurricane season. In it, I wrote that “the combination of warm water and a weakening El Niño probably suggests an active hurricane season ahead in 2024.” I also noted that you’d probably be seeing some aggressive seasonal outlooks. Consider that article from AccuWeather to be a first or second volley. It’s important to note a couple things though. As is often the case, it’s the buzzwords that grab people’s attention and leads to accusations of hype in some circles. But the content of their actual article is fundamentally sound! There is one element I take issue with, and that’s their description of the Texas coast being at higher risk than usual for the upcoming season.

Forecasting landfall patterns consistently this far ahead of time is really, really hard. I’ve never found anyone that has done it successfully and at a consistent level. Anyone can claim they nailed a seasonal call this far out, but they’ve probably also had 50 false alarms to go with their handful of victories. Colorado State University, which releases a highly anticipated outlook each season has actually put their verification metrics online, and they did well this past season. But while they offer a landfall probability table by state, they are intentionally broad in their discussion, because specifically narrowing down a section of, say, a state’s coastline being at higher risk than another is difficult. If Texas is at higher risk, does that mean Louisiana is not? What of Mexico? At what point does “higher risk” kick in?

I don’t want to fault anyone or say I am against seasonal forecasts. I am not. But we have to be extremely careful how specific we get in February. The peak of hurricane season is still about six and a half months away.

So where do we stand now?

If you read last month’s post, the general takeaway was that there was no reason to forecast anything other than an active hurricane season in 2024. How active and how bad was TBD. Has anything changed since then? Not really.

First, a look at sea surface temperatures (SSTs) shows that the Atlantic remains obscenely warm. Obscenely warm.

Seeing this in February is truly remarkable, as these readings, specifically in the Main Development Region are more normal for July. It’s February 21st, so a lot can change between now and June or July or August. But, suffice to say, this is as strong a signal for an active hurricane season as you would likely ever see. So, the SST checkbox is checked for “Active” for another month.

What about El Niño? Well, there are ample signs that it is beginning to wane as expected. The animation below shows SST anomalies from the Equatorial Pacific Ocean from the ocean surface (top) to 450 meters below the surface (bottom). Notice how a lot of the deep warm water, particularly on the right side of the image (the Eastern Pacific) gets eroded away in the last few frames. That’s a sign of colder water making a return to the ocean’s subsurface in the Pacific. It won’t take much to begin to wind down the El Niño from this point.

Again, it’s not uncommon for an El Niño as strong as this one to quickly weaken in springtime. And it appears this year will fit that trend. But where it goes from here is equally important in terms of how it may impact hurricane season. The latest long range forecast from a slew of government agencies shows about 2/3 of ensemble members taking us to La Niña by mid-summer and about 1/3 holding us back.

Ensemble forecasting is the best approach most times, especially at this timeframe because instead of one deterministic outcome, we get to see generally what the consensus is and where any reasonable subset of outliers exists. I look at these charts frequently, and a couple items stand out right now. First, the majority take us into La Niña by July, if not June. Second, some of these model members really take us into La Niña, perhaps moderately so by mid-summer. However, there is also a subset of members that pull a Lee Corso, trying to drift us back into El Niño after dragging us back to near neutral. The takeaway here is that the odds seem to favor La Niña, and indeed, NOAA did recently issue a La Niña Watch. But there is still some inherent uncertainty, and oh yeah, we are in what is termed the “spring predictability barrier,” which is a fascinating study in how models can be truly imperfect. I do think they’re getting better at this and perhaps this barrier isn’t as strong as it once was. But the stench of busted forecasts past does still linger in close enough proximity for me to proceed with caution.

So, the verdict? An exceptionally warm Atlantic Ocean, and odds favoring La Niña development this summer continue to suggest an active hurricane season ahead. But where those storms go, how strong they are, and when they’ll be at their worst is a forecast that is close to impossible to make at this juncture. As always, if you live in a hurricane-prone region, the best advice in any hurricane season is to be prepared as if that season were the one.