third-strongest hurricane to hit the U.S. mainland by wind speed (165 mph; 265 km/h). Meteorological history A tropical wave moved off the west coast of Africa on August 14. A ridge of high pressure to its north caused the wave to move quickly westward. An area of convection developed along the wave axis to the south of the Cape Verde islands, and on August 15, meteorologists began classifying the system with the Dvorak technique. The thunderstorm activity became more concentrated, and narrow spiral rainbands began to develop around a center of circulation. It is estimated that Tropical Depression Three developed late on August 16, about east-southeast of Barbados. Embedded within the deep easterlies, the depression tracked west-northwestward at . Initially, moderate wind shear prevented strengthening, until a decrease in shear allowed the depression to intensify into Tropical Storm Andrew at 12:00 UTC on August 17. By early August 18, the storm maintained convection near the center with spiral bands to its west as the winds increased to . Shortly thereafter, the storm began weakening because of increased southwesterly wind shear from an upper-level low. On August 19, a Hurricane Hunters flight into the storm failed to locate a well-defined center and on the following day, a flight found that the cyclone had degenerated to the extent that only a diffuse low-level circulation center remained; observations indicated the barometric pressure rose to an unusually high . The flight indicated that Andrew maintained a vigorous circulation aloft. After the upper-level low weakened and split into a trough, the wind shear decreased over the storm. A strong high pressure system then developed over the southeastern United States, which built eastward and caused Andrew to turn to the west. Convection became more organized as upper-level outflow became better established. An eye formed, and Andrew attained hurricane status early on August 22, about east-southeast of Nassau, Bahamas. In the forecast issued six hours after becoming a hurricane, the cyclone was predicted to make landfall near Jupiter, Florida, with winds of 105 mph (170 km/h) on August 25. This underestimated both the strength and the speed of the storm, which would eventually make landfall in South Florida. The hurricane accelerated westward into an area of highly favorable conditions, and began to rapidly intensify late on August 22; in a 24‑hour period the atmospheric pressure dropped by to a minimum of . On August 23, the storm