Tropical Storm Olaf (1997)

The origins of Olaf were from a tropical wave first noted over Central America on September 22. It moved slowly through the eastern Pacific Ocean, and gradually developed an area of convection. Concurrently, an upper-level low-pressure area moved from the Gulf of Mexico across Mexico into the Pacific, which produced wind shear across the region; wind shear is the difference in wind speed and direction in the atmosphere, and is usually harmful to tropical cyclogenesis. The disturbance associated with the tropical wave persisted and developed outflow. This caused the upper-level low to move away from the system. On September 26, it was sufficiently organized to be classified Tropical Depression Seventeen-E, while located about 345 miles (555 km) south of the Gulf of Tehuantepec.^[1]

A few hours after developing, the depression attained tropical storm status, or winds of at least 40 mph (64 km/h). Upon doing so, the National Hurricane Center (NHC) gave it the name "Olaf". The upper-level low, which was moving away from the region, caused the storm to move northward toward the Mexican coast. Olaf quickly intensified, as evidenced by reports from a nearby ship, and the winds reached 70 mph (110 km/h) by late on September 27; the NHC anticipated further intensification to hurricane status, or winds of at least 75 mph (121 km/h). Instead, interaction with the rough terrain of Mexico caused weakening. Olaf made landfall on Salina Cruz, Oaxaca early on September 29 as a 35 mph (56 km/h) tropical depression. Within a few hours, the circulation was not evident on satellite imagery, and the NHC discontinued advisories.^[1]

Despite being considered dissipated, a re-analysis of satellite imagery indicated the circulation of Olaf persisted as turned to the west toward open waters. Early on September 30, the system reached the Pacific, and it continued westward for about a week, during which it retained some convective activity. On October 5, Olaf turned toward the east, as it interacted with the large circulation of developing Hurricane Pauline. Later that day, the NHC resumed issuing advisories, while it was located about 560 miles (900 km) southwest of the southern tip of the Baja California Peninsula.^[1] The system turned to the southeast, and, failing to organize, the NHC discontinued advisories on October 8. Three days later, after the remnants of Olaf turned toward the north, the NHC again resumed advisories, when it was just 70 miles (110 km) south-southwest of Tecomán, Colima.^[2] Late on October 12, the circulation of Olaf made its final landfall near Manzanillo, Colima, and it quickly dissipated. An associated area of thunderstorms moved over open waters again, but failed to redevelop.^[1]