2024 Atlantic hurricane season

The 2024 Atlantic hurricane season was an extremely active and destructive Atlantic hurricane season that became the third-costliest on record, behind only 2017 and 2005. The season featured 18 named storms, 11 hurricanes, and 5 major hurricanes; it was also the first since 2019 to feature multiple Category 5 hurricanes. Additionally, the season had the highest accumulated cyclone energy (ACE) rating since 2020, with a total value of 161.5 units. The season officially began on June 1 and ended on November 30. These dates, adopted by convention, have historically described the period in each year when most subtropical or tropical cyclogenesis occurs in the Atlantic Ocean.

The first system, Tropical Storm Alberto, developed on June 19 and then made landfall near Tampico, Tamaulipas, the next day. Afterward, two storms formed at the end of June, with the first, Hurricane Beryl, being a rare June major hurricane and only the second known Category 5 Atlantic hurricane in July, attaining this status on the earliest recorded date. Beryl caused significant impacts, especially in the Windward Islands and Texas, with over $9 billion in damage and 73 fatalities. Next, Tropical Storm Chris formed on June 30 and quickly moved ashore Veracruz. Activity then went dormant for more than three weeks. In early August, Hurricane Debby developed in the Gulf of Mexico before striking Florida and South Carolina. Shortly thereafter came Hurricane Ernesto, which impacted the Lesser Antilles, Puerto Rico, Bermuda, and parts of Atlantic Canada in mid-August. After an unusual lull in activity in late August and early September, Hurricane Francine formed in the western Gulf of Mexico, then made landfall in Louisiana, inflicting about $1.3 billion in damage.

Activity dramatically increased in late September. Hurricane Helene developed over the western Caribbean and later made landfall in the Big Bend region of Florida at Category 4 strength, leading to disastrous flooding over central Appalachia that caused more than $78.7 billion in damage and 252 deaths. October was also very active, with four named storms developing during the month, all but one of which became hurricanes. The strongest, Hurricane Milton, formed in the Gulf of Mexico and explosively intensified into a Category 5 hurricane; it was also the most intense tropical cyclone worldwide in 2024. Milton later made landfall near Siesta Key, Florida, on October 9, as a Category 3 hurricane. The storm caused at least 39 deaths and $34.4 billion in damage, mostly in Florida. In mid-October, Tropical Storm Nadine and Hurricane Oscar formed in quick succession. The former quickly struck Belize while the latter achieved the smallest hurricane-force wind field on record in the Atlantic. It struck Grand Turk Island and Cuba. In early November, Hurricane Rafael struck western Cuba at Category 3 strength. In mid-November, the last system, Tropical Storm Sara, drifted along the north coast of Honduras before striking Belize, while producing widespread heavy rainfall resulting in severe flash flooding and mudslides across northern Central America. Collectively, the cyclones of the 2024 season caused about $131 billion in damage and 442 fatalities.

All forecasting agencies predicted an above-average season, primarily due to expected warmer-than-normal sea surface temperatures and a low risk for an El Niño. Although the season ultimately finished above-average, a heat dome mostly suppressed early activity, while little tropical cyclogenesis occurred from mid-July to mid-September due to the Saharan air layer (SAL), atmospheric stability, strong wind shear, and an unfavorable Madden–Julian oscillation pattern.

Seasonal forecasts

In advance of, and during, each hurricane season, several forecasts of hurricane activity are issued by national meteorological services, scientific agencies, and noted hurricane experts. These include forecasters from the United States National Oceanic and Atmospheric Administration (NOAA)'s Climate Prediction Center, Tropical Storm Risk (TSR), the United Kingdom's Met Office (UKMO), and Colorado State University (CSU). The forecasts include weekly and monthly changes in significant factors that help determine the number of tropical storms, hurricanes, and major hurricanes within a particular year.

According to NOAA and CSU, the average Atlantic hurricane season between 1991 and 2020 contained roughly 14 tropical storms, 7 hurricanes, 3 major hurricanes, and an accumulated cyclone energy (ACE) index of 72–111 units. Broadly speaking, ACE is a measure of the power of a tropical or subtropical storm multiplied by the length of time it existed. It is only calculated for full advisories on specific tropical and subtropical systems reaching or exceeding wind speeds of 39 mph (63 km/h). NOAA typically categorizes a season as above-average, average, or below-average based on the cumulative ACE index, but the number of tropical storms, hurricanes, and major hurricanes within a hurricane season is sometimes also considered.

Pre-season forecasts

On December 11, 2023, TSR released its extended range forecast for the 2024 season, predicting an above-average season with 20 named storms, 9 hurricanes, and 4 major hurricanes. They took into account ongoing warm sea-surface temperatures (SSTs) throughout most of the basin, specifically in the Main Development Region and in the Caribbean Sea on top of the 2023–2024 El Niño event which was predicted to weaken to a neutral phase by August 2024. CSU released its first forecast on April 4, calling for an extremely active hurricane season, with 23 named storms, 11 hurricanes and 5 major hurricanes, with an ACE index of 210 units, citing the extremely warm Atlantic SSTs and the development of a La Niña by the summer. On April 5, Météo-France (MFM) issued a prediction of 21 named storms and 11 hurricanes. They cited warm SSTs, wind patterns, and humidity. TSR updated their forecast on April 8, predicting 23 tropical storms, 11 hurricanes, and 5 major hurricanes, with an ACE index of 217 units. They predicted that moderate La Niña conditions would occur in the summer and persist into fall and above average SSTs would also persist into summer. The University of Arizona (UA) posted their forecast on the same day, calling for a very active season featuring 21 named storms, 11 hurricanes, 5 major hurricanes, and an ACE index of 156 units. On April 12, University of Missouri (MU) issued their prediction of 26 named storms, 11 hurricanes, and 5 major hurricanes. North Carolina State University (NCSU) issued their prediction on April 16, with 15–20 named storms, 10–12 hurricanes, and 3–4 major hurricanes. On April 24, the University of Pennsylvania (UPenn) issued their prediction of a record-breaking season, predicting an unprecedented 33 (±6) named storms. They cited expected moderate La Niña conditions and record-warm SSTs in the tropical Atlantic tied to large-scale warming.

On May 6, the Servicio Meteorológico Nacional (SMN) issued their forecast of 20–23 tropical storms, 9–11 hurricanes, and 4–5 major hurricanes. On May 22, UKMO published their forecast for the 2024 season, calling for 22 named storms, 12 hurricanes, and 4 major hurricanes, and an ACE index of 212 units. One day later, NOAA published their hurricane season prediction, forecasting an above-average season of 17–25 named storms, 8–13 hurricanes, and 4–7 major hurricanes with an 85% chance of being an above-average season. TSR updated their predictions on May 30 with 24 tropical storms, 12 hurricanes, and 6 major hurricanes with an ACE of 226.

Mid-season forecasts

On June 11, CSU also updated its predictions, continuing to expect an extremely active season, with 23 tropical storms, 11 hurricanes, five major hurricanes, and an ACE of 210. On June 23, UA updated its prediction with 23 named storms, 10 hurricanes, five major hurricanes, and an ACE of 231. TSR updated its predictions on July 5 with 26 tropical storms, 13 hurricanes, and six major hurricanes with an ACE of 240. On July 9, CSU updated its predictions, anticipating an even more active season, with 25 tropical storms, 12 hurricanes, six major hurricanes, and an ACE of 230. On August 8, NOAA updated its prediction of the total number of named storms slightly, while still anticipating a highly active season.

Seasonal summary

Background

Officially, the 2024 Atlantic hurricane season began on June 1 and ended on November 30. In all, 18 tropical cyclones formed, and all of them became named storms. Of those, 11 storms intensified into hurricanes and 5 strengthened into major hurricanes. Additionally, one potential tropical cyclone that was designated did not develop into a tropical cyclone. Three hurricanes made landfall in Florida during the season – only the sixth such occurrence since records began, after 1871, 1886, 1964, 2004, and 2005. Overall, five hurricanes struck the continental United States, tied with 1893, 2004, and 2005 for the second-most. This season's ACE index, as calculated officially by the National Hurricane Center (NHC), was approximately 161.5 units, the highest value recorded since 2020. This number represents the sum of the squares of the maximum sustained wind speed (knots) for all named storms while they are at least tropical storm intensity, divided by 10,000. Overall, the cyclones of the 2024 Atlantic hurricane season collectively caused about 442 fatalities and at least $131 billion in damage, making it the third-costliest on record, behind only 2017 and 2005.