The 2020 Atlantic hurricane season was the most active Atlantic hurricane season on record in terms of number of named storms. Additionally, it was an above-average season for tropical cyclones for the fifth consecutive year.[nb 1][2] The season officially began on June 1, 2020, and ended on November 30, 2020. These dates, adopted by convention, historically delimit the period each year when most Atlantic tropical systems form.[3] However, storm formation is possible at any time of the year, as was the case this season, when its first two named storms, Tropical Storm Arthur and Tropical Storm Bertha, formed on May 16 and May 27, respectively. The final storm, Hurricane Iota, dissipated on November 18.
Altogether, the season produced 31 tropical or subtropical cyclones, all but one of which became a named storm. Of the 30 named storms, 14 became hurricanes, and seven further intensified into major hurricanes.[nb 2] It was the second and final season to use the Greek letter storm naming system, the first being 2005.[5]Hurricane Laura produced catastrophic storm surge levels, heavy rainfall, and spawned over a dozen tornadoes after striking Louisiana on August 27 with winds of 150 mph (240 km/h). The storm was responsible for 81 deaths and it caused over US$19 billion in damage across the Greater Antilles and the Southern United States.[6] Causing significant late-season loss of life and widespread destruction were November hurricanes Eta and Iota, which made landfall in Central America as Category 4 storms just two weeks apart.[2] The storms left a toll of 184 deaths and 110 missing across the region, and thousands of families lost their homes and livelihoods.[7] In March 2021, the names Laura, Eta and Iota were retired from reuse in the North Atlantic by the World Meteorological Organization due to the extraordinary amount of damage and number of fatalities they caused.[8]
This timeline documents tropical cyclone formations, strengthening, weakening, landfalls, extratropical transitions, and dissipations during the season. It includes information that was not released throughout the season, meaning that data from post-storm reviews by the National Hurricane Center, such as a storm that was not initially warned upon, has been included.
By convention, meteorologists use one time zone when issuing forecasts and making observations: Coordinated Universal Time (UTC), and also use the 24-hour clock (where 00:00 = midnight UTC).[9] The National Hurricane Center uses both UTC and the time zone where the center of the tropical cyclone is currently located. The time zones utilized (east to west) are: Greenwich, Cape Verde, Atlantic, Eastern, and Central.[10] In this timeline, all information is listed by UTC first, with the respective regional time zone included in parentheses. Additionally, figures for maximum sustained winds and position estimates are rounded to the nearest 5 units (knots, miles, or kilometers), following National Hurricane Center practice. Direct wind observations are rounded to the nearest whole number. Atmospheric pressures are listed to the nearest millibar and nearest hundredth of an inch of mercury.
12:00 UTC (8:00 a.m. AST) at 39°24′N62°42′W / 39.4°N 62.7°W / 39.4; -62.7 (Dolly transitions into tropical storm) – Subtropical Storm Dolly transitions into a tropical storm and simultaneously reaches its peak intensity with 45 mph (72 km/h) maximum sustained winds and minimum barometric pressure of 1,000 mbar (30 inHg), while located about 370 mi (600 km) south-southeast of Halifax.[14]
06:00 UTC (2:00 a.m. AST) at 9°42′N46°36′W / 9.7°N 46.6°W / 9.7; -46.6 – Tropical Storm Gonzalo reaches its peak intensity of 65 mph (105 km/h) maximum sustained winds and minimum barometric pressure of 997 mbar (hPa; 29.44 inHg), while located about 690 mi (1,110 km) east of the southern Windward Islands.[17]
18:00 UTC (1:00 p.m. CDT) at 26°54′N96°48′W / 26.9°N 96.8°W / 26.9; -96.8 – Hurricane Hanna attains its peak intensity with maximum sustained winds of 90 mph (140 km/h) and minimum barometric pressure of 973 mbar (28.7 inHg), just off the coast of South Texas.[18]
12:00 UTC (7:00 a.m. CDT) at 24°18′N87°12′W / 24.3°N 87.2°W / 24.3; -87.2 (Marco becomes a hurricane) – Tropical Storm Marco strengthens to a Category 1 hurricane about 210 mi (340 km) northwest of the western tip of Cuba, and simultaneously reaches its peak intensity with maximum sustained winds of 75 mph (120 km/h) and minimum pressure of 991 mbar (29.3 inHg).[25]
12:00 UTC (8:00 a.m. EDT) at 34°36′N73°42′W / 34.6°N 73.7°W / 34.6; -73.7 (Tropical Storm Omar forms) – Tropical Depression Fifteen strengthens into Tropical Storm Omar about 115 mi (185 km) southeast of Cape Hatteras, North Carolina, and simultaneously reaches its peak intensity with sustained winds of 40 mph (64 km/h) and a minimum pressure of 1,003 mbar (29.6 inHg).[26]
03:00 UTC (10:00 p.m. CDT, September 2) at 16°54′N87°30′W / 16.9°N 87.5°W / 16.9; -87.5 (Nana becomes a Hurricane) – Tropical Storm Nana becomes a Category 1 hurricane about 60 mi (97 km) southeast of Belize City, Belize, and simultaneously reaches its peak intensity with sustained winds of 75 mph (121 km/h) and a minimum central pressure of 994 mbar (29.4 inHg).[27]
Five simultaneous tropical cyclones active in the Atlantic on September 14: Sally (left), Paulette (center left), Rene (center right), Teddy (bottom right), and Vicky (far right)
12:00 UTC (8:00 a.m. AST) at 20°30′N30°48′W / 20.5°N 30.8°W / 20.5; -30.8 (Vicky at peak intensity) – Tropical Storm Vicky reaches its peak intensity with sustained winds of 50 mph (80 km/h) and a pressure of 1,001 mbar (29.6 inHg), about 435 mi (700 km) northwest of the northwesternmost of the Cabo Verde Islands.[33]
^Hurricanes reaching Category 3 (111 miles per hour (179 km/h)) and higher on the 5-level Saffir–Simpson wind speed scale are considered major hurricanes.[4]
^According to the NHC's protocol, a tropical cyclone that degenerates into a remnant low in one basin and regenerates in another is given a different name. Since Amanda, a Pacific tropical storm, degenerated over Central America, the regenerated Atlantic tropical cyclone was given the next name on the Atlantic list, Cristobal.[13]
^Due to the threat the system posed as it formed to the countries and territories in the eastern Caribbean, the National Hurricane Center initiated advisories on the system as Potential Tropical Cyclone Nine at 15:00 UTC (11:00 a.m. AST) on July 28.[19][20]
^At the time, the National Hurricane Center did not name the system at that point because it was unclear whether it had a well-defined low-level-circulation.[27] However, with the storm posing an imminent threat to Central America, the National Hurricane Center initiated advisories on the system as Potential Tropical Cyclone Sixteen that day at 15:00 UTC (10:00 a.m. CDT).[28]
^The determination that the system had become a subtropical storm at around 06:00 UTC (6:00 a.m. GMT) on September 17 was made by the National Hurricane Center during post-storm analysis.[34] At the time, it was determined that Subtropical Storm Alpha had formed at 16:30 UTC (4:30 p.m. GMT) on September 18 as it was approaching the coast of Portugal.[35]
^Operationally, the National Hurricane Center continued issuing advisories on Tropical Depression Eta due to uncertainties about whether or not the surface circulation had dissipated.[45][46]
^"Central America: Hurricanes Eta and Iota"(PDF). Humanitarian Situation Report No.7. Panama City, Panama: UNICEF Latin America and Caribbean Regional Office. January 2021. Archived(PDF) from the original on August 27, 2021. Retrieved June 18, 2021.
^ abcdJohn Beven; Robbie Berg (March 31, 2021). Tropical Cyclone Report: Tropical Storm Fay(PDF) (Report). Miami, Florida: National Hurricane Center. Archived(PDF) from the original on June 22, 2021. Retrieved April 17, 2021.
^ abcdefghDaniel Brown; Robbie Berg; Brad Reinhart (February 11, 2021). Tropical Cyclone Report: Hurricane Hanna(PDF) (Report). Miami, Florida: National Hurricane Center. Archived(PDF) from the original on June 22, 2021. Retrieved April 17, 2021.
^ abcdefghijklAndrew Latto; Andrew Hagen; Robbie Berg (April 15, 2021). Tropical Cyclone Report: Hurricane Isaias(PDF) (Report). Miami, Florida: National Hurricane Center. Archived(PDF) from the original on September 18, 2021. Retrieved April 17, 2021.
^ abcdefghijklmnopqrsRichard Pasch; Robbie Berg; David Roberts; Philippe Papin (May 26, 2021). Tropical Cyclone Report: Hurricane Laura(PDF) (Report). Miami, Florida: National Hurricane Center. Archived(PDF) from the original on September 2, 2021. Retrieved May 28, 2021.
^ abcdefghijRobbie Berg; Bard Reinhart (April 14, 2021). Tropical Cyclone Report: Hurricane Sally(PDF) (Report). Miami, Florida: National Hurricane Center. Archived(PDF) from the original on April 14, 2021. Retrieved April 21, 2021.
^ abcdefghijkEric Blake; Robbie Berg; Andrew Hagen (May 10, 2021). Tropical Cyclone Report: Hurricane Zeta(PDF) (Report). Miami, Florida: National Hurricane Center. Archived(PDF) from the original on September 2, 2021. Retrieved May 11, 2021.
