September 10 is the climatological peak of the Atlantic hurricane season, but the basin has reached that benchmark without producing a single hurricane.
Through Thursday morning, four named storms - Bertha, Cristobal, Dolly and Edouard - had formed in the Atlantic basin. None strengthened beyond tropical storm status. That is a strikingly slow start for a season that typically ramps up during late August and early September, especially considering how active recent years have been.
It is not quite a record, at least not yet. The latest a first Atlantic hurricane formed in the satellite era was on Sept. 11, in the 2002 and 2013 seasons. If the basin remains hurricane-free through Friday, 2026 would set a new satellite-era mark for the latest first hurricane. As of Thursday morning, the National Hurricane Center outlook showed no organized activity expected over the next 7 days, so this record almost certainly will fall.
That "satellite-era" distinction matters because earlier hurricane records are less certain. Before weather satellites became available in the 1960s, storms that stayed over open water could be missed. In the modern observing era, however, it is rare even to enter September without a hurricane. Just seven previous satellite-era seasons had done so, according to recent hurricane-season analyses.
The slow start does not mean Connecticut can dismiss the rest of the season. The Atlantic season runs through Nov. 30, and history has delivered plenty of late surprises (you may remember Hurricane Sandy occurred in late October). A quiet basin still can produce one storm with significant effects, including coastal flooding, damaging wind, heavy rain or rough surf far from a storm's center.
The largest background factor this year is a rapidly strengthening El Niño, the periodic warming of the tropical Pacific Ocean that can alter weather patterns around the world.
NOAA's Climate Prediction Center said in its September update (issued Thursday morning) that El Niño had strengthened significantly and has a 75% chance of becoming the strongest on record, since at least 1950.
For the Atlantic, El Niño tends to increase vertical wind shear, which is the change in wind speed or direction with height. Hurricanes need thunderstorms to remain stacked vertically over their centers. Strong winds high in the atmosphere can tilt and displace those storms, making it much harder for a tropical system to organize or intensify.
El Niño is not a hurricane shutoff switch. Warm Atlantic water, tropical moisture, Saharan dust, African easterly waves and shorter-lived weather patterns all play roles. But NOAA already had called for a below-normal Atlantic season, and the season's early behavior has closely matched the expected suppressing influence of El Niño. NOAA's hurricane researchers note that its impact often becomes more apparent from September into November, essentially the heart of the season.
While the Atlantic has struggled, the eastern Pacific has been notably more active and intense.
Through Thursday, the eastern Pacific had produced nine named storms, including five hurricanes and three major hurricanes. Hurricanes Genevieve and Lowell each reached Category 5 strength, while Karina became a Category 4 storm. Including two systems in the central Pacific brings the broader eastern-and-central-Pacific tally to 11 named storms, six hurricanes and four major hurricanes.
That does not make the Pacific season record-breaking by every seasonal metric - NOAA's 1991-2020 average is 15 named storms, eight hurricanes and four major hurricanes in the eastern Pacific - but the concentration of high-end storms has been remarkable. At one point last week, Marie, Karina and Lowell all were hurricanes at the same time.
It is also a familiar El Niño pattern. The same large-scale changes that foster wind shear over the Atlantic can leave parts of the eastern and central Pacific with warmer water and a more favorable atmosphere for tropical development. NOAA's preseason eastern Pacific outlook gave that basin a 70% chance of above-normal activity, which is currently on track to become reality.
For Connecticut (along with any coastal state), the Atlantic's quiet start is a welcome break from the tumultuous tropics of years past, but it is not an all-clear. The calendar still has plenty of hurricane season left.
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This article originally published at Atlantic hurricane season reaches its peak with no hurricanes. What it means for Connecticut.