Hurricane Marco was the first of two tropical cyclones to threaten the Gulf Coast of the United States within a three-day period, with the other being Hurricane Laura. The thirteenth named storm and third hurricane of the record-breaking 2020 Atlantic hurricane season, Marco developed from a fast-moving tropical wave west of the Windward Islands and south of Jamaica on August 20. The fast motion of the wave inhibited intensification initially, but as the wave slowed down and entered a more favorable environment, the system developed into a tropical depression, which in turn rapidly intensified into a strong tropical storm. Due to strong wind shear, Marco's intensification temporarily halted; however, after entering the warm waters of the Gulf of Mexico on August 23, Marco briefly intensified into a hurricane, only to quickly weaken later that evening due to another rapid increase in wind shear. Marco subsequently weakened to a tropical depression before degenerating into a remnant low early the next morning. Marco's remnants subsequently dissipated on August 26. Heavy rains across the Yucatán Peninsula caused river rises and flooding throughout the region. One person was indirectly killed in Tapachula, Mexico, due to the storm, although this was not included in the official death toll. Impacts in the United States were generally minor, as the storm was quite weak when it impacted the Gulf Coast. Meteorological history At 00:00 UTC on August 16, the National Hurricane Center (NHC) began monitoring a westward-moving tropical wave over the Central Atlantic that had the potential for development. The disturbance quickly moved westward at a speed over , which initially limited its development as it passed through the Windward Islands and into the Caribbean Sea. The system slowed down and gradually organized south of the Greater Antilles on August 19. By 15:00 UTC on August 20, satellite imagery revealed that the wave had developed a well-defined low-level center, prompting the NHC to designate it Tropical Depression Fourteen. Post-storm analysis found that the system formed nine hours earlier at 06:00 UTC. At the time the system was located east of the Nicaragua–Honduras border. The storm continued westward toward Honduras, before making a sharp turn northward. Despite favorable conditions, the storm initially failed to intensify, with pulsing convection around a poorly defined center. Eventually, the storm's center became better defined and a small but persistent cluster of convection formed over it. This allowed the depression to intensify, and