The seventh tropical storm and second hurricane of the season, Florence developed on September 7 from an area of convection associated with a dissipating frontal trough in the southern Gulf of Mexico.

Located in an area of generally low pressures, the system developed a spiral band structure, though deep convection was mostly intermittent.

Subsequent to the formation of a surface circulation, the system developed into a tropical depression while located about 450 miles (720 km) northwest of Mérida, Yucatán.

[1] The depression drifted eastward under the influence of the dissipating frontal trough, and intensified into Tropical Storm Florence to the north of the Yucatán Peninsula, as confirmed by Hurricane Hunters.

Steadily intensifying, Florence attained hurricane status about 100 miles (160 km) south of the mouth of the Mississippi River.

The hurricane intensified slightly further, and struck the western Mississippi River Delta with winds of 80 mph (130 km/h) at 0200 UTC on September 10.

By the time it passed over New Orleans and Lake Pontchartrain most convection had dissipated, and about ten hours after making landfall Florence degenerated into a tropical depression.

The system subsequently crossed over southwestern Mississippi as it turned northwestward, and later entered northern Louisiana before dissipating over northeastern Texas on September 11.

[5] Prior to the arrival of the hurricane, an estimated 20,000 people evacuated the coastal parishes of southeastern Louisiana, including nearly all of the 2,000 residents on Grand Isle.

[7] The threat of the hurricane caused Democratic presidential nominee Michael Dukakis to cancel a rally and two fund-raising events in New Orleans.

[9] The primary rainband extending southward from the circulation of Florence dropped moderate rainfall across the Yucatán Peninsula and through southern Mexico.

[4] Upon making landfall on Louisiana, Hurricane Florence produced higher than normal tides, including a peak observation of 7.5 feet (2.3 m) above mean sea level on the Bayou Benvenue to the east of New Orleans.

Precipitation reached over 3 inches (76 mm) in extreme southeastern Missouri, southern Illinois, and central Ohio, and extended as far northward as Michigan.