Hurricane Isaias was a destructive Category 1 hurricane that caused extensive damage across the Caribbean and the East Coast of the United States while also spawning the strongest tropical cyclone-spawned tornado since Hurricane Rita in 2005. The ninth named storm and second hurricane of the extremely active and record-breaking 2020 Atlantic hurricane season, Isaias originated from a vigorous tropical wave off the coast of Africa that was first identified by the National Hurricane Center on July 23. The tropical wave gradually became more organized and obtained gale-force winds on July 28 before organizing into Tropical Storm Isaias on July 30. Isaias marked the earliest ninth named storm on record, surpassing 2005's Hurricane Irene by eight days. Isaias strengthened into a Category 1 hurricane on the next day, reaching an initial peak of 85 mph (137 km/h), with a minimum central pressure of 987 mbar. On August 1, the storm made landfall on North Andros, Bahamas and subsequently weakened to a tropical storm, before paralleling the east coast of Florida and Georgia. As Isaias approached the Carolina coastline, it reintensified back into a hurricane. Soon afterward, Isaias reached its peak intensity, with maximum 1-minute sustained winds of 90 mph (140 km/h) and a minimum central pressure of 986 millibars (29.1 inHg), before making landfall near Ocean Isle Beach, North Carolina, at 03:10 UTC on August 4, at the same intensity. The storm proceeded to accelerate up the East Coast of the United States as a strong tropical storm, before transitioning into an extratropical cyclone over Quebec on August 4. Isaias's extratropical remnants persisted for another day, before dissipating on August 5.

The Saffir–Simpson hurricane wind scale (SSHWS) classifies hurricanes—which in the Western Hemisphere are tropical cyclones that exceed the intensities of tropical depressions and tropical storms—into five categories distinguished by the intensities of their sustained winds. This measuring system was formerly known as the Saffir–Simpson hurricane scale, or SSHS.