MEXICO CITY (Reuters) - Tropical Storm Sonia weakened as it approached the Pacific coast of Mexico on Sunday, but threatened heavy rains over swaths of western Mexico that have experienced major flooding over the past couple of months.
Sonia was churning 115 miles east of the southern tip of the Baja California peninsula and the center of the storm was expected to reach the mainland coast early on Monday, the Miami-based U.S. National Hurricane Center said in its latest advisory.
The weather system was traveling north-northeast at 17 miles per hour with maximum sustained winds of 40 mph, the NHC said. The storm was expected to weaken rapidly after making landfall and dissipate over Mexico on Monday afternoon, it added.
A tropical storm warning was in effect for a stretch of the coast from the resort city of Mazatlan north to the town of Altata, both in Sinaloa state.
Sonia was expected to produce rainfall of 3 to 10 inches in both Sinaloa and Durango states, the NHC said.
Mexico's national water commission said heavy rains could extend to more than half a dozen other western and northern states.
In September, Mexico suffered its worst flooding since records began when storms Manuel and Ingrid converged from the Pacific and the Gulf of Mexico, killing more than 150 people and causing damage estimated at around $6 billion.
Last month, Hurricane Raymond caused some flooding as it approached the Pacific resort cities of Acapulco and Zihuantanejo, but no deaths or major damage was reported.
Sonia is the 18th named storm system during the current eastern Pacific hurricane season, which began in May and is set to conclude at the end of this month.
(Reporting by David Alire Garcia and Noe Torres; Editing by Simon Gardner and Sandra Maler)