Three Landfalls in One Weekend » Yale Climate Connection

Oscar is the third named storm to hit a Caribbean island in 2024.

• On July 1, Hurricane Beryl struck Carriacou, Grenada as a Category 4 high-end hurricane, causing catastrophic damage and killing at least five people in the Lesser Antilles.
• Hurricane Ernesto passed through the Leeward Islands as a tropical storm on August 13 and 14 with winds of 45 to 65 mph, causing $150 million in damage but no fatalities, according to Gallagher Re.

Another “El Chapo” from The Atlantic

Nadine lasted only 12 hours as a tropical storm, making it the fourth named storm (“short”) of the 2024 Atlantic hurricane season to last two days or less at tropical storm or hurricane strength. The others were Alberto (one day), Chris (six hours) and Gordon (two days). The number of these short-lived storms has increased significantly in recent decades. As we wrote in a lengthy article in 2021, this growth could increase significantly by looking at how the system changes over time.

Likewise, Oscar was a very small hurricane, with an eye diameter of only 3.5 miles; therefore, in the days before routine satellite monitoring, the event easily went unnotified. The Oscar's compact size also makes it easier to spin and gain power than larger Storms.

Nadine and Oscar are the first two storms to be named Atlantic Storms of 2024, forming on the same day. They arrived amid a burst of late-season activity, including the disastrous U.S. landings of Category 4 Helene and Category 5 Milton and the impressive high-seas trek of Category 4 Kirk.

A series of activities at the end of the season

Despite a mysterious pause in activity during the peak of the season in late August and early September, tropical cyclone activity in the Atlantic in 2024 was above average in all categories, and the number of hurricanes was also well above average (see below Bluesky post) ).

Including Nadine and Oscar, the Atlantic has 15 named storms, 10 hurricanes, 4 major hurricanes, and an accumulated cyclone energy (ACE) index of 143. A hurricane.

So while the 2024 Atlantic hurricane season is not as hyperactive as many seasonal forecasters expected, it will certainly far exceed a typical hurricane season in terms of potency and impact, and we may also see one or more additional before the end of the system.

Calm Pacific, crazy Atlantic: this year’s intense tropical activity

After Helen and Milton's disastrous one-two punch – and given the record warmth that has gripped much of the world's oceans – it would be easy to assume that the planet has been awash with hurricanes and typhoons over the past few months. But in fact, it is mainly the Atlantic Ocean that is active.

The other three ocean basins that produce Northern Hemisphere tropical cyclones – the northwest Pacific, northeast Pacific and northern India – have so far seen activity well below seasonal averages. Here's how cumulative cyclone energy (ACE) as of October 20 compares to the 1991-2020 year-to-date average, compiled by Colorado State University (CSU):

Atlantic: 143.9 (average 109.5) = 31% above average
Northeast Pacific: 59.9 (average 124.6) = 52% below average
Pacific Northwest: 119.3 (average 233.8) = 51% below average
North India: 3.3 (average 12.1) = 73% below average

Tropical activity in the North Pacific is typically more than twice that of the North Atlantic. So even this year's Atlantic storms like Beryl, Helen, Kirk and Milton won't be enough to make up for the calm Pacific. As of October 20, the ACE total for the entire Northern Hemisphere was 326.4, less than two-thirds of the long-term average to date. Even if the 2024 total increases by 10% by Dec. 31, it will still end up being the second quietest year in the Northern Hemisphere in 45 years of reliable satellite data tracked by Colorado State University.

It is not unusual for some basins in the Northern Hemisphere to be very active while others are sluggish. Features such as the El Niño-Southern Oscillation tend to enhance activity in some basins while suppressing activity in others. Even if one or two basins are active or even hyperactive, this usually leaves the hemispheric average not far from normal. When the tropical Pacific moves toward La Niña during the northern summer and fall (as is the case now), conditions tend to favor tropical activity in the North Atlantic and reduce tropical activity across the North Pacific—which is exactly what happens, though It's particularly dramatic.