Continuous onshore flow from Sally caused storm surge flooding to occur on Dauphin Island beginning early on September 14. Two unoccupied riverboat casinos in Bayou La Batre near Mobile broke loose due to the constant wave action with one of them hitting a dock. Fort Morgan, Alabama reported a wind gust of 121 miles per hour (195 km/h) while Mobile reported a wind gust of 83 miles per hour (134 km/h). Major structural damage was recorded at the landfall point in Gulf Shores as well as Mobile. A pier in Gulf Shores that was destroyed in Hurricane Ivan in 2004 was partially destroyed again by storm surge from Sally just days after it had reopened following renovations. There were also several reports of damage to condos in the Gulf Shores with a few being destroyed. Meanwhile, in Downtown Mobile, a street light snapped, swinging wildly on its cable. A gas station was destroyed in Spanish Fort, Alabama. Several sewage overflows were reported across Mobile County following heavy rain from Hurricane Sally, causing contamination to Dog River and Rabbit Creek. One person was declared dead and one other missing in Orange Beach, an area most impacted by flooding. Another person died in Foley during the storm cleanup process. Over 2,000 broken poles and 4,300 trees on power lines left over 71,000 households and businesses in southern and central Baldwin County without power, representing 95% of the service area of a local electrical cooperative, Baldwin EMC. Only 5 of 22 substations remained in service the day after the storm. Two days after landfall, on September 18, Alabama governor Kay Ivey said in a news conference that 103,000 customers were still without power in Baldwin County, and another 60,000 in Mobile County. Five days after landfall, Baldwin EMC had restored power to close to 60,000 meters, representing 75% of their subscribers, but 18,197 meters remained without power.
Hurricane Sally was a destructive and slow-moving Atlantic hurricane that was the first hurricane to make landfall in the U.S. state of Alabama since Ivan in 2004, coincidentally on the same date in the same place. The eighteenth named storm and seventh hurricane of the extremely active 2020 Atlantic hurricane season, Sally developed from an area of disturbed weather which was first monitored over the Bahamas on September 10. The system grew a broad area of low-pressure on September 11, and was designated as a tropical depression late that day. Early the next day, the depression made landfall at Key Biscayne and subsequently strengthened into Tropical Storm Sally that afternoon. Moderate northwesterly shear prevented significant intensification for the first two days, but convection continued to grow towards the center and Sally slowly intensified. On September 14, a center reformation into the center of the convection occurred, and data from a hurricane hunter reconnaissance aircraft showed that Sally had rapidly intensified into a strong Category 1 hurricane. However, an increase in wind shear and upwelling of colder waters halted the intensification and Sally weakened slightly on September 15 before turning slowly northeastward. Despite this increase in wind shear, it unexpectedly re-intensified, reaching Category 2 status early on September 16 before making landfall at peak intensity at 09:45 UTC on September 16, near Gulf Shores, Alabama, with maximum sustained winds of 110 mph (180 km/h) and a minimum central pressure of 965 millibars (28.5 inHg). The storm rapidly weakened after landfall before transitioning into an extratropical low at 12:00 UTC the next day. Sally's remnants lasted for another day as they moved off the coast of the Southeastern United States before being absorbed into another extratropical storm on September 18.
On September 4, a surface trough formed on the south and southwest side of then-Tropical Depression Omar near Bermuda. Omar would dissipate the next day and its remnants moved northeastward while the trough moved slowly south-southwestward over the Western Atlantic over the next several days, showing little to no signs of organization. At 00:00 UTC on September 10, the NHC began to monitor the area of disturbed weather as it was over the Bahamas for possible development. Over the next two days, convection rapidly increased, became better organized, and formed a broad area of low-pressure on September 11. At 18:00 UTC, the system had organized enough to be designated as Tropical Depression Nineteen. Just after 06:00 UTC on September 12, the depression made landfall near Cutler Bay, Florida, with winds of 35 mph (56 km/h) and a pressure of 1,003 mbar (29.6 inHg). The system maintained its strength as it moved west over Florida, but the NHC noted that a strong convective burst near the center of the cyclone had weakened considerably. Despite this, the depression strengthened over land and became Tropical Storm Sally at 12:00 UTC that same day while over The Everglades, becoming the earliest 18th tropical or subtropical storm in an Atlantic hurricane season, surpassing the old mark of October 2, which was previously set by Hurricane Stan in 2005. As Sally moved offshore into the Gulf of Mexico at around 15:00 UTC and turned north-northwestward, it strengthened some more to 60 mph (97 km/h) before northwesterly shear from a nearby upper-level low halted its intensification and gave the system a sheared appearance. As shear relaxed some and became westerly, a huge burst of convection and a center reformation caused Sally to rapidly intensify into a hurricane by 16:00 UTC on September 14 before reaching its initial peak intensity with winds of 85 mph (137 km/h) and a pressure of 986 mbar (29.1 inHg). Operationally, the NHC upgraded the storm to low-end Category 2 status at 21:00 UTC, but this was determined to be due to transient eyewall features and not a true estimate of the storm's intensity.
A state of emergency was declared on the night of Sunday, September 13, 2020. Mississippi governor Tate Reeves urged residents to prepare for Sally, which he said could produce up to 20 inches (51 cm) of rain in the southern part of the state. Some shelters were opened, although officials urged people who were evacuating to stay with friends, relatives, or in hotels, if possible, because of the threat of coronavirus superspreading. Mandatory evacuations were ordered for parts of Harrison County and Hancock County.
Alabama governor Kay Ivey closed all beaches on the coast and called for evacuations of low-lying and flood prone areas. Additionally, Dauphin Island mayor Jeff Collier strongly encouraged all people to evacuate the west end after water started to encroach on the main roadway. A state of emergency was declared by governor Kay Ivey on September 14, 2020, as public schools and university classes were either cancelled or moved online in anticipation of the storm.