The storm moved generally northwestward and steadily intensified despite only a marginally favorable environment for development, and became a Category 2 hurricane before making two landfalls on the Baja California peninsula and mainland Mexico.

The hurricane was responsible for significant flooding and storm surges that caused $100 million (2003 USD) in damage mostly on the peninsula of Baja California, and resulted in the deaths of 12 people.

[1] Marty began moving north-northwestward in response to a high pressure ridge to the west, and continued to strengthen, reaching a peak intensity of 100 mph (160 km/h) early on September 22.

Marty then moved northward at an increased speed before making landfall 10 mi (16 km) northeast of Cabo San Lucas in Baja California Sur later that day.

[1][2] After making landfall, Marty turned back to the north-northwest, moving parallel to the eastern coast of the peninsula, and weakening to a tropical storm on September 23.

Marty then stalled over the Gulf of California after encountering a high pressure system over the U.S. state of Nevada, and further weakened to a tropical depression before making a second landfall near Puerto Peñasco, Sonora, on September 24.

[1] Fearing a repeat of the damage left by Hurricane Ignacio a month earlier, many residents stocked up on supplies, secured their homes and evacuated to emergency shelters.

[1] Forecasters also predicted that the hurricane might cause 4–6 feet (1.2–1.8 m) of storm surge, 8 inches (20 cm) of rain, serious flash flooding, and mudslides.

[1] As a result, the Baja California Sur municipalities of La Paz, Los Cabos, Loreto, Comondú, and Mulegé were declared national disaster areas.