Tropical Storm Javier is forming off Mexico's Pacific Coast, the US National Hurricane Center says, even as the death toll from last week's Hurricane Earl grew to 11.
Javier had sustained winds of about 45 mph (75kph) and was located about 110 miles (175km) west of Manzanillo.
The storm was moving west-northwest at about 12 mph (19kph).
Forecasters said Javier should pass over or near the coast and then approach the resort-dotted southern portion of the Baja California Peninsula on Monday.
Heavy rains of between 4 and 8 inches (10 to 20cm) were expected, along with high winds.
A tropical storm warning was in effect from Manzanillo to Cabo Corrientes.
A tropical storm watch is in effect from the southern part of the Baja California peninsula to Santa Fe.
Javier arrives in the wake of Earl, which was briefly a hurricane before hitting Belize and the Yucatan Peninsula, dumping rain and triggering deadly landslides across parts of eastern Mexico.
The governor of the Gulf Coast state of Veracruz, Javier Duarte, said on Sunday that 10 people had died in landslides in the towns of Cocomatepec, Tequila and Huayacocotla.
Officials earlier reported six dead.
Also on Sunday, officials in the central state of Puebla reported at least one death in a landslide in the mountain town of Xaltepec that destroyed 13 homes.
Authorities were still searching the area for residents who were reported missing, according to a statement from the state government.
Earl struck Belize last week as a Category 1 hurricane, ripping off roofs and downing power lines.
It also passed over Guatemala and southern Mexico before regaining strength over the Gulf of Mexico and making a second landfall on Veracruz's coastline late on iday.
