List of Atlantic tropical storms
The classification Atlantic tropical storm is used to refer to a tropical cyclone that forms in the North Atlantic Ocean with 1-minute maximum sustained wind speeds from 39 mph (63 km/h) to 72 mph (117 km/h). Tropical cyclones that attain such winds and move over land while maintaining those winds are capable of causing minor to moderate damage to human lives and infrastructure. Since the Atlantic hurricane database (HURDAT) began in 1851, there have been 761 tropical storms recorded,[a][1] as well as 92 others not recognized by HURDAT, but recognized by the International Best Track Archive for Climate Stewardship (IBTrACS) as possible tropical storms,[2] in the North Atlantic tropical cyclone basin, which is denoted as the part of the Atlantic Ocean north of the equator. This list does not include tropical storms that later intensified into hurricanes.
The development of tropical storms in the North Atlantic basin is influenced by many factors. During the Northern Hemisphere winter and spring months of December to April, sea surface temperatures in the tropics are usually too low to support tropical cyclogenesis, and there are multiple high-pressure systems, such as the Azores High, that also inhibit tropical cyclogenesis. These effects are reduced or even disappear during hurricane season from May to November, when sea surface temperatures are also high enough to support tropical cyclogenesis; the bulk of recorded tropical storms developed during June to November. Global weather patterns may also influence hurricane development in the North Atlantic. El Niño events result in reduced numbers of powerful hurricanes through stronger wind shear and lower sea surface temperatures within the basin, while La Niña events increase the number of such hurricanes through the opposite.
Background
On the Saffir–Simpson scale, a tropical cyclone reaches tropical storm status when it attains maximum sustained winds of between 34 knots (39 mph; 63 km/h; 17 m/s) and 63 knots (72 mph; 117 km/h; 32 m/s).[3] The National Hurricane Center (NHC) defines sustained winds as the average wind speed measured over the period of one minute at the height of 10 metres (33 ft) above the ground.[4] Should a tropical storm make landfall, its strongest winds are not especially damaging, and are unlikely to cause damage to any sturdy structure, but can often make trees and their branches fall. A larger danger is a tropical storm's rainfall, which can cause major flooding, as in the case of Tropical Storm Allison, and a slow-moving system can cause severe loss of life.[5][3]
The North Atlantic tropical cyclone basin is defined as the region of the Atlantic Ocean north of the equator, while other boundaries are mainly established by land areas. The main bodies of water included in the Atlantic basin are the North Atlantic Ocean, the Gulf of Mexico, and the Caribbean Sea.[6] Storms that form in the South Atlantic Ocean or in the Mediterranean Sea are not part of the Atlantic basin. The Regional Specialized Meteorological Center (RSMC) for the North Atlantic basin is the NHC, which manages the warnings of tropical cyclones there.[7] On average from 1980 to 2024, an average of 13.6 storms of at least tropical storm strength form in one year, though the number can range from only four in 1983 to thirty in 2020. Of these storms, 6.9 reach hurricane intensity; meaning that 6.7 peak as tropical storms.[8] All tropical cyclones recorded by past and present RSMCs of the North Atlantic basin since 1851 are listed in the North Atlantic hurricane database (HURDAT), which is compiled and maintained by the National Hurricane Center.[1]
Climatology
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| Decade | Number of storms |
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Hurricane season in the Atlantic Ocean, during which 97% of storms form, begins on June 1 and ends on November 30. Those that form outside of this time period are known as off-season storms.[9] Since 1851, a total of 761 tropical storms have developed in the North Atlantic Ocean. 35 have occurred in the off-season, 80 in June, 65 in July, 151 in August, 222 in September, 158 in October, and 50 in November.[1]
The formation and development of tropical cyclones, termed tropical cyclogenesis, requires high sea surface temperatures of at least 26.5 °C (79.7 °F) at least as deep as 50 m (160 ft), a sharp temperature difference between the lower and upper atmospheres, moist air and low vertical wind shear. When these conditions are met, a pre-existing tropical disturbance – usually a tropical wave – can develop into a tropical cyclone, provided the disturbance is far enough – at least 500 km (310 mi) – from the Equator to experience a sufficiently strong Coriolis force to exhibit the counterclockwise rotation[10] and low pressure of tropical cyclones in the Northern Hemisphere.[11] Although most storms are found within tropical latitudes, occasionally storms will form further north and east from disturbances other than tropical waves such as cold fronts and upper-level lows. These are known as baroclinically induced tropical cyclones.[12]
Sea surface temperature is more constant than land temperature due to the higher heat capacity of water; thus, it takes longer for the ocean to warm up in the summer than it does the land.[13] On average, the first Atlantic tropical storm of the year usually forms in mid-to-late June.[6] Tropical activity is significantly lower in July and early August, despite higher sea surface temperatures, due to the Saharan air layer – dust from the Sahara desert that blows west each summer – suppressing tropical cyclogenesis.[14][15] In the summer, the subtropical ridge, which is not conducive to tropical cyclogenesis, moves northward, expanding the area for storms to form.[16] The hurricane season peaks in mid-September, with the two-month period between mid-August and mid-October seeing most activity.[6]
Within tropical latitudes, prevailing winds generally cause Atlantic tropical cyclones move west, though the presence of strong middle and upper-level winds can induce northward or northwestward movement instead. Influenced by the subtropical ridge, the general direction of storms upon reaching the mid-latitudes is northeast, causing them to curve back to sea and away from land.[6][16]
There is a strong correlation between Atlantic hurricane activity in the tropics and the presence of an El Niño or La Niña in the Pacific Ocean. El Niño sees a warming of the tropical Pacific, while La Niña exhibits cooling in that area: both have far-reaching effects around the world. El Niño events increase the wind shear, especially westerlies, over the Atlantic, producing a less favorable environment for formation and decreasing tropical activity in the Atlantic basin. Conversely, La Niña causes an increase in activity due to a decrease in wind shear.[17][18]
Tropical storms can take a variety of different tracks across the Atlantic Ocean. As they are weaker, they do not require as high a sea surface temperature, and they are more likely to form in unusual areas, such as Tropical Storm Grace, the northernmost-forming tropical cyclone in the Atlantic;[19] Tropical Storm Christine, the easternmost-forming tropical cyclone in the Atlantic;[20] or Tropical Storm Delta, which hit Morocco as an extratropical cyclone, the first storm ever to do so.[21]
Systems
See also
Notes
- ↑ This total does not include subtropical storms.
References
- 1 2 3 "Atlantic hurricane best track (HURDAT version 2)" (Database). United States National Hurricane Center. April 4, 2025.
This article incorporates text from this source, which is in the public domain.
- Landsea, Chris (April 2022). "The revised Atlantic hurricane database (HURDAT2) - Chris Landsea – April 2022" (PDF). Hurricane Research Division – NOAA/AOML. Miami, Florida: Hurricane Research Division – via Atlantic Oceanographic and Meteorological Laboratory.
- ↑ "International Best Track Archive for Climate Stewardship (IBTrACS)". International Best Track Archive for Climate Stewardship. National Oceanographic and Atmospheric Administration. Retrieved August 12, 2022.
- 1 2 Schott, Timothy; Landsea, Christopher W; Hafale, Gene; Lorens, Jeffrey; Taylor, Arthur; Thurm, Harvey; Ward, Bill; Willis, Mark; Zaleski, Walt (February 1, 2012). "The Saffir–Simpson Hurricane Wind Scale" (PDF). Miami, Florida: United States National Hurricane Center. Archived (PDF) from the original on 2016-12-13. Retrieved May 24, 2018.
- ↑ Landsea, Christopher W (April 21, 2006). "TCFAQ D4) What does "maximum sustained wind" mean? How does it relate to gusts in tropical cyclones?". Atlantic Oceanographic and Meteorological Laboratory. Archived from the original on 2014-10-09. Retrieved May 24, 2018.
- ↑ "Tropical Cyclone Flooding: A Deadly Inland Danger" (PDF). National Weather Service. National Oceanic and Atmospheric Administration. March 2005. Retrieved July 24, 2025.
- 1 2 3 4 "Tropical Cyclone Climatology". National Hurricane Center. Retrieved 4 November 2017.
- ↑ Landsea, Christopher W (June 1, 2018). "TCFAQ F1) What regions around the globe have tropical cyclones and who is responsible for forecasting there?". Atlantic Oceanographic and Meteorological Laboratory. Archived from the original on November 13, 2012. Retrieved July 26, 2022.
- ↑ "Hurricanes: Frequently Asked Questions". Atlantic Oceanographic and Meteorological Laboratory. National Oceanic and Atmospheric Administration. June 1, 2023. Retrieved July 30, 2023.
- ↑ Dorst, Neal (June 2, 2016). "TCFAQ G1) When is hurricane season?". Atlantic Oceanographic and Meteorological Laboratory. Archived from the original on May 6, 2009. Retrieved July 27, 2022.
- ↑ "The Coriolis Effect: Earth's Rotation and Its Effect on Weather". National Geographic. Retrieved May 24, 2026.
In the Northern Hemisphere, fluids from high-pressure systems pass low-pressure systems to their right. As air masses are pulled into cyclones from all directions, they are deflected, and the storm system—a hurricane—seems to rotate counter-clockwise.
- ↑ Landsea, Christopher W (2014). "TCFAQ A15) How do tropical cyclones form?". Atlantic Oceanographic and Meteorological Laboratory. Archived from the original on August 27, 2009. Retrieved July 27, 2022.
- ↑ Christopher A. Davis & Lance F. Bosart (November 2003). "Baroclinically Induced Tropical Cyclogenesis". Monthly Weather Review. 131 (11). American Meteorological Society: 2730. Bibcode:2003MWRv..131.2730D. doi:10.1175/1520-0493(2003)131<2730:BITC>2.0.CO;2. ISSN 1520-0493.
- ↑ "A Comparison of Land and Ocean Temperature Anomalies". Florida Atlantic University. April 3, 2023. Retrieved December 25, 2025.
- ↑ Kay, Christana (July 17, 2024). "The tropics turned eerily quiet after Hurricane Beryl. Why?". WAPT. Jackson, Mississippi. Retrieved July 24, 2024.
- ↑ Jason P. Dunion; Christopher S. Velden (2004). "The Impact of the Saharan Air Layer on Atlantic Tropical Cyclone Activity". Bulletin of the American Meteorological Society. 85 (3). American Meteorological Society: 353–366. doi:10.1175/BAMS-85-3-353.
- 1 2 Van Voorhees, Brittany (October 4, 2023). "Why hurricanes go west when other weather travels east". WCNC Charlotte. Retrieved May 24, 2026.
- ↑ Landsea, Christopher W; Dorst, Neal M (1 June 2014). "Subject: G2) How does El Niño-Southern Oscillation affect tropical cyclone activity around the globe?". Tropical Cyclone Frequently Asked Question. United States National Oceanic and Atmospheric Administration's Hurricane Research Division. Archived from the original on 9 October 2014.
- ↑ Bove, Marc C.; O'Brien, James J.; Landsea, Christopher W.; Niu, Xufeng; Elsner, James B. (November 1, 1998). "Effect of El Niño on U.S. Landfalling Hurricanes, Revisited". Bulletin of the American Meteorological Society. 79 (11). American Meteorological Society: 2477–2482. Bibcode:1998BAMS...79.2477B. doi:10.1175/1520-0477(1998)079<2477:EOENOO>2.0.CO;2. Retrieved August 28, 2025.
- ↑ Robbie Berg (28 November 2009). "Tropical Storm Grace Tropical Cyclone Report" (PDF). United States National Hurricane Center. Retrieved 22 November 2015.
- ↑ Paul J. Herbert; Neil L. Frank (January 28, 1974). "Atlantic Hurricane Season of 1973" (PDF). United States National Hurricane Center. Archived (PDF) from the original on March 3, 2016. Retrieved November 24, 2022.
- ↑ National Hurricane Center. "Tropical Cyclone Report: Tropical Storm Delta" (PDF). NOAA. Retrieved 2006-05-29.