MONTERREY, Mexico, Oct 12 (Reuters) - Hurricane Pamela gathered strength on Tuesday as it barreled toward Mexico"s western coast, with the U.S. National Hurricane Center (NHC) predicting it will strengthen further before crashing into the fertile farm state of Sinaloa. Sinaloa is the country"s top grower of corn, Mexico"s staple grain, as well as a major producer of tomatoes and other fruits that figure prominently in the country"s agricultural exports to the United States. The Category 1 hurricane was located about 280 miles (450 km) south of the major Sinaloa beach resort of Mazatlan, the latest NHC advisory showed. Pamela packed maximum sustained winds of 80 miles per hour (130 kph) early Tuesday morning, the NHC said, with the center forecasting "steady to rapid strengthening" before reaching land at almost major hurricane strength early on Wednesday. Pamela is expected to drench Sinaloa, which in recent months has been hit by dry weather seen potentially hitting agricultural production. A tropical storm watch extends from the fishing village of Los Barriles on the Sea of Cortes side of Mexico"s Baja peninsula down to the southern tip at Cabo San Lucas. But Pamela"s fury is seen mostly targeting Mexico"s southwest mainland, with "large and destructive waves" near the coast and rainfall of between 4 and 12 inches (10 and 30 cm) seen hitting both Sinaloa and the neighboring state of Durango. The hurricane was churning northward at about 13 miles per hour (21 kph) early Tuesday. "This rainfall may trigger significant and life-threatening flash flooding and mudslides," the NHC added. Last year, Sinaloa alone produced more than 380,000 tonnes of tomatoes, or nearly a fifth of national output and overwhelmingly destined for export, according to government data.