The 2020 Atlantic hurricane season was an annual period of tropical cyclone formation in the Northern Atlantic that ran from May 30 to November 18. 2020 was the record-breaking sixth season to begin before the official start date, June 1, sparking much media coverage over the possibility that the limits of the season could be changed to an earlier start date. However, the World Meteorological Agency (WMO) reiterated that no changes were being considered at the time. Aside from the early start date, the season featured fairly average activity, with twelve named storms, seven hurricanes, and three major hurricanes of category 3 strength or greater.
By far the most intense and damaging storm was Hurricane Josephine, which tied with Hurricane Allen of 1980 as the strongest Atlantic hurricane in terms of wind speed. The storm passed just to the north of most of the Leeward Isles and Greater Antilles, with much of the catastrophic core staying offshore. As a result, despite its strength, Josephine caused significantly less damage than expected. The entire season as a whole saw a relatively low amount of damage and fatalities; both were at their lowest since the 2015 season.
Seasonal summary
Systems
Subtropical Storm Arthur
| Subtropical storm (SSHWS) | |
  | |
| Duration | May 30 – May 31 |
|---|---|
| Peak intensity | 60 mph (95 km/h) (1-min) 999 mbar (hPa) |
Subtropical Storm Arthur originated from a disturbed area of weather southwest of Jamaica. The disorganized cluster of thunderstorms slowly drifted to the northwest and began interacting with a cold front, which pulled it north. A secondary low developed as the cold front began to weaken and began retreating. Initially, Arthur's precursor remained embedded in the frontal boundary, causing it to accelerate. However, by the afternoon hours of May 29, reconnaissance aircraft observed that separation had begun. Baroclinic forcing allowed the low to intensify fairly quickly, and by the time Subtropical Storm Arthur was declared at 00:00 UTC on May 30, winds had increased to 50 mph (85 km/h). Just two hours after classification, Arthur moved ashore in the Big Bend region of Florida, near the town of Steinhatchee. By daylight hours, the center of the storm had already reemerged over the Atlantic Ocean, and impacts had concluded in much state. Continuing to the northeast, Arthur encountered the Gulf Stream and began strengthening once again. The storm peaked at 00:00 UTC on May 31 with winds of 60 mph (95 km/h) and a minimum pressure of 999 millibars. Shortly after reaching peak intensity, Arthur's appearance began to rapidly degrade as the cyclone approached a cold front. Twelve hours later, the center became embedded in the frontal boundary, and Arthur was declared post-tropical at 12:00 UTC that same day.
Arthur's effects in Cube, Mexico, and the United States were minimal. In the Caribbean, impacts were restricted to some occasional heavy rainfall. The most serious effects in the United States occurred in Florida, where heavy rainfall and wind caused disruptions in the northern parts of the state. In other parts of the Southeast, heavy rainfall and occasional winds caused issues for travel. In total, one person was killed by Arthur when a tree was uprooted by wind and fell on a mobile home.
Hurricane Bertha
| Category 1 hurricane (SSHWS) | |
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| Duration | June 14 – June 17 |
|---|---|
| Peak intensity | 75 mph (120 km/h) (1-min) 990 mbar (hPa) |
The beginnings of Hurricane Bertha can be traced back to a disorganized area of showers and thunderstorms. As is usual with June tropical cyclone formations in the Gulf of Mexico, Bertha's precursor was originally embedded in the Central American Gyre. An area of low pressure developed within the broad circulation of the gyre and gradually moved to the northwest into the Bay of Campeche. Over water, the low struggled to organize, as it was still entangled with the larger gyre system. Initially drifting southwestwards, the low turned to the northwest and finally began to show signs of organization. After several days of very slow development, Tropical Depression Two was finally declared at 06:00 UTC on June 14. Initial forecasts expected the depression to remain weak and disorganized, but those quickly began to change when Two was upgraded to a tropical storm at 00:00 UTC on June 15, receiving the name Bertha. After becoming a tropical storm, Bertha turned to the west under the influence of a high pressure to its northeast. The warm waters of the Gulf of Mexico and relatively low wind shear allowed for further strengthening to occur as the cyclone headed for the Mexican coast. By midday on the 15th, hurricane warnings were put into effect for a large swath of the Mexican coast. Just hours before landfall, Bertha reached hurricane strength and slowed down drastically, prolonging effects in the area. The hurricane came ashore at peak intensity just north of the major port city of Tampico at 12:00 UTC on June 16; at time of landfall, sustained winds were at 75 mph (120 km/h), while the minimum pressure had bottomed out at 990 millibars. After landfall, Bertha rapidly weakened over the dry Mexican terrain. By June 17, the storm had weakened to a depression, and advisories were discontinued at 06:00 UTC later that day as Bertha degenerated into a remnant low.
Bertha caused serious disruption in northern Veracruz and southern Tamaulipas states. The storm made landfall in Tamaulipas, just north of Tampico. The shipping and oil industry of the region was heavily disrupted by the storm, with debris filling the vital Pánuco River waterway. Considerable flooding occured in parts of central and northern Tamaulipas, as well as mudslides in the Sierra Madre Oriental mountains. In total, 7 fatalities were reported as a result of Bertha. Property damage was estimated around $800 million (2020 USD).
Tropical Storm Cristobal
| Tropical storm (SSHWS) | |
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| Duration | July 5 – July 8 |
|---|---|
| Peak intensity | 45 mph (75 km/h) (1-min) 1004 mbar (hPa) |