Tropical Depression 15-E formed on Oct. 12 at 11 p.m. EDT and strengthened into Tropical Storm Octave. Four days later NASA's Terra satellite saw the weakened storm headed for landfall in western Mexico.
TD15-E formed about 470 miles/755 km south of the southern tip of Baja California, near 16.1 north and 110.2 west. By 5 a.m. EDT on Oct. 13, TD15-E became Tropical Storm Octave. Octave's maximum sustained winds peaked at 65 mph/100 kph at 11 p.m. EDT on Oct. 13 when it was about 215 miles/345 km northwest of Socorro Island, near 20.6 north and 113.7 west.
The Moderate Resolution Imaging Spectroradiometer aboard NASA's Terra satellite saw Tropical Storm Octave in the Gulf of California and Tropical Storm Priscilla in the open waters of the Eastern Pacific on Oct. 14 at 2:40 p.m. EDT.
By 5 p.m. EDT/2100 UTC on Oct. 15, Octave had become a post-tropical cyclone. It was located near latitude 26.9 north and longitude 109.4 west in the Gulf of California, about 80 miles/130 km north-northwest of Los Mochis, Mexico. Maximum sustained winds decreased to near 25 mph/35 kph.
The post-tropical cyclone was moving toward the north-northeast near 5 mph/7 kph and that general motion continued until the system moved over mainland Mexico between Guaymas and Los Mochis. Although Octave dissipated on Oct. 16 the remnants brought large rainfall totals to mainland Mexico, between 3 to 6 inches over the state of Sonora.
Explore further: NASA watching Hurricane Paul, warnings up for Baja California