NOAA forecasts a busy hurricane season – but not like 2020.
Tick tock. As May winds down, the tropical waters are heating up. In fact, there’s a decent chance we’ll get our first named storm of the season tomorrow or Saturday.
Government scientists at NOAA and the National Hurricane Center have released their prediction for this hurricane season – 13 to 20 named storms, 6 to 10 hurricanes, with 3 to 5 of them Category 3 or above.
So taking the midpoints of the ranges, NOAA’s forecast calls for 16 or 17 named storms, including 8 hurricanes with 4 of them reaching Category 3 or above.
Officially, the average number of named storms in a season is 14, so this forecast is decently above normal. But is 14 really the number we should think of as normal?
Probably not. Modern stats almost certainly understate modern reality.
The number 14 is based on the average over the years 1991 to 2020, but times and technology have changed significantly since the 90s. These days we have much higher-resolution satellite pictures, doppler radar coverage from inside the storms, and data from a number of sources that didn’t exist 25 years ago.
This means that we now name systems that technically meet the requirements, but old-school technology wouldn’t have detected.
In addition, the earth continues to warm, so the tropical ocean temperatures are edging up, and we’ve seen consistent warming at higher latitudes – technically the subtropics – and along the U.S. coast. As a result, systems that track over these warmer waters have a better chance of developing.
The net result is that an extra named storm or two is likely more “normal” in the modern era. Even 30-year averages may be too long to be representative in a fast-changing world.
The bottom line is that the forecast is about in line with an adjusted normal for the modern era, or slightly above.
Also of note, the predictions are less certain this year than last, when pretty much everybody was on the bandwagon for a very busy season – although Mother Nature still exceeded expectations. This year, the tropical Atlantic is not especially warm and the El Niño/La Niña situation – the biggest driver of Atlantic tropical activity – is more or less neutral so far.
Some neutral years are blockbusters, and some years are fairly quiet. So the signals this year are not strong. And when signals are weak, changes sometimes occur after the season gets started.
In any case, as interesting as all that is, it only takes one nasty storm to change everything. So preparation is essential, and now’s the time to figure out your hurricane plans.
Out in the middle of the Atlantic, a strong wintertime storm system is spinning. It is forecast to drift in the general direction of Bermuda over the next couple of days, and move over warmish subtropical waters. By tomorrow, it’s forecast to be strong enough and organized enough to rate a name, which would be Subtropical Storm Ana.
Even if that happens, it’s expected to move out to sea, and not threaten land.
It’s a giant circulation extending deep in the atmosphere, however. The flow of air on the left side of the system is strong enough to push some cooler, drier air in the direction of a South Florida for the weekend. A nice bonus since we’ve officially entered the rainy season.
So welcome to Hurricane Season 2021!
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Let’s hope for a quiet hurricane season. But don’t bet on it.