Sandra strengthened to a Category 3 storm, becoming the strongest ever recorded in the eastern Pacific for this late in the year.
The storm is centered about 570 miles (915 kilometers) south of Manzanillo, Mexico, and is moving west near 13 mph (20 kph).
Rick is centered about 445 miles (715 kilometers) west-southwest of Manzanillo, Mexico, and is moving west-northwest at 12 mph (19 kph).
Rick is centered about 340 miles (547 kilometers) southwest of Manzanillo, Mexico.
The newly-formed system is expected to strengthen to Tropical Storm Rick in the coming days.
Many tourists were earlier ordered by staff at their hotels to make for the city's convention center, which was designated by emergency services as a main shelter.
En Cihuatlán, Jalisco, decenas de casas se inundaron
Los pobladores saben que el impacto del fenómeno más poderoso del planeta —como lo calificaron las autoridades— podría ser mayor
Forecasters say the storm is capable of "potentially catastrophic" damage.