A Timeline of Tropical Storm Harvey’s Development

Harvey made landfall in Texas on Friday night as the strongest hurricane to hit the U.S. in more than a decade. By Saturday afternoon it had been downgraded into a tropical storm, but it had dumped 18 inches of rain on some areas and forecasters were warning that it could cause catastrophic flooding in the coming days.

Here is a timeline of key moments in the storm’s development:

Aug. 17, 4 p.m. Tropical Storm Harvey is named, six hours after the National Hurricane Center in Miami issues a potential tropical cyclone for several small Caribbean islands.

Aug. 19, 4 p.m. Moving westward between the northern coast of South America and the larger Caribbean islands, Harvey is downgraded to a tropical depression, with maximum sustained winds of 35 mph. Six hours later, it is further downgraded to a tropical wave.

Wednesday, 10 a.m. Harvey regenerates into a tropical depression about 535 miles southeast of Port O’Connor, Texas, with maximum sustained winds of 35 mph.

Thursday, 1 p.m. After quickly strengthening over the course of a day, Harvey becomes a hurricane, with maximum sustained winds of 85 mph. It is about 325 miles southeast of Port O’Connor, and Texas coastal communities in its path are urged to complete their preparations. By midnight, it is upgraded to a Category 2 hurricane and is 220 miles from Port O’Connor, with sustained maximum winds of 100 mph.

Friday, 2 p.m. Harvey is upgraded to a Category 3 hurricane, with sustained maximum winds of 120 mph (195 kph). It is centered about 75 miles (120 kilometers) southeast of Corpus Christi. By 6 p.m., Harvey is a Category 4 storm just 45 miles from the city, with maximum sustained winds of 130 mph (215 kph).

Friday, 10 p.m. Harvey makes landfall as a Category 4 hurricane when the eye of the storm comes ashore between Port Aransas and Port O’Connor, two communities on a spit off the coast of mainland Texas near Corpus Christi.

Shabbos, 2 a.m. Harvey is centered about 15 miles inland and is weakening as it slowly passes over land. It has been downgraded to a Category 3, with maximum sustained winds of 115 mph. Two hours later, it is downgraded further to a Category 2.

Shabbos, 5 a.m. With maximum sustained winds of 90 mph, Harvey is downgraded to a Category 1 storm. Forecasters warn of potentially catastrophic flooding in the coming days.

Hours later, it is downgraded yet again to a tropical storm and is blamed for its first death — that of a person in Rockport, which sustained heavy damage.