A science review of Hurricane Andrew: 30 years later

TALLAHASSEE, Fla. (WCTV) - One of the most destructive hurricanes to hit The Sunshine State hit South Florida 30 years ago on Wednesday.

Hurricane Andrew made it’s first U.S. landfall on Aug. 24, 1992 at around 5 a.m. east of Homestead, Fla. The hurricane contributed to 23 direct deaths in the U.S., according to NOAA. It also destroyed over 25,000 homes and damaged another 100,000, and 99% of mobile homes in the Homestead area were destroyed.

Andrew started like most other tropical cyclones: A lone tropical wave moving westward off the African coast in the eastern Atlantic. It had enough thunderstorm activity near a center of circulation to be classified as a tropical depression on Aug. 16, according to the report from the National Hurricane Center.

The next day, the depression became the first tropical storm of the 1992 Atlantic hurricane season. Andrew moved west to west-northwest. As it approached a trough of low pressure aloft, the storm began to shift to a northwesterly trek between Aug. 17 and Aug. 20. This also placed Andrew into a high-wind-shear environment where convection near the storm’s center “was stripped away” to where hurricane reconnaissance aircraft found only a diffuse low-level circulation was all that remained of Andrew.

By Aug. 21, the trough moved away and decreased the wind shear. An upper-level low moved in place to the southwest of Andrew and helped to provide some ventilation for the storm. Meanwhile, a large high pressure cell set up north of Andrew in the Atlantic. The trough to its southwest helped to intensify the storm while the high steered the storm nearly due west.

Andrew became a hurricane on Aug. 22 and was on the border of becoming a Category 4 and 5 on the Saffir-Simpson hurricane wind scale.

The potent hurricane was originally believed to be a Category 4 hurricane as it passed over Eleuthera Island in the Bahamas and when it made landfall in Florida in the early morning hours of Aug. 24. Re-analysis over a decade after Andrew found that the maximum sustained winds were “stronger than was analyzed earlier,” according to researchers and forecasters from NOAA. The 2004 paper that was published in the Bulletin of the American Meteorological Society detailed the review of GPS-containing dropwindsondes and adjustments used to determine surface winds from data gathered at flight level.

The authors of that 2004 paper determined that maximum sustained winds as Andrew made landfall in Florida were at Category-5 strength and reached 145 knots, or around 167 mph.

Andrew was still intensifying as it crossed South Florida, according to the post-storm report, and emerged into the Gulf of Mexico later that morning.

The ridge of high pressure that was steering Andrew began to weaken, and began to move more northwestward. A trough of low pressure aloft moving eastward from the Plains helped to shift Andrew’s track to a more northerly one. It made its final landfall west-southwest of Morgan City, La. on Aug. 26, 1992. It was a Category 3 hurricane at landfall, and weakened to a tropical depression nearly 12 hours later.

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