Forming off the western coast of Mexico, Hurricane Roslyn has strengthened into a major Category 3 storm and is expected to make landfall this weekend, forecasts show. Roslyn has sustained winds of 120 mph as of early Saturday morning and is moving west-northwest parallel to the southwestern Mexican coast, according to the National Hurricane Center. Roslyn’s sustained wind speed increased by 60 mph in a 24-hour period from Friday to Saturday morning, signifying a rapid intensification. A storm undergoes rapid intensification when its maximum sustained winds increase at least 35 mph in 24 hours or less. Hurricane conditions are forecast along the coast of Mexico by Saturday night, bringing “damaging winds and a dangerous storm surge,” the National Hurricane Center said. Las Islas Marias — an archipelago roughly 60 miles off the mainland coast — is under a hurricane warning as of Saturday morning, as are parts of the west-central mainland coast from Playa Perula to El Roblito. A hurricane warning is often issued 36 hours in advance of tropical-storm-force winds, and any preparations made before the storm’s arrival should be rushed to completion. The current track shows Roslyn continuing to gain strength, potentially becoming a Category 4 hurricane by Saturday night. The storm may weaken some before landfall on Sunday but is still forecast to be at or near major hurricane strength before reaching the Mexican state of Nayarit, according to the hurricane center. Widespread rainfall totals of 4 to 6 inches are forecast for portions of Mexico including Colima, Jalisco, western Nayarit, Islas Marias and southeastern Sinaloa, near where the storm makes landfall. Some isolated rainfall totals up to 8 inches are possible. “This rainfall could lead to flash flooding and landslides in areas of rugged terrain,” the hurricane center said. Dangerous storm surge will also bring significant coastal flooding near and to the east of where the center of Roslyn makes landfall on Sunday, the hurricane center added. The storm is tracking similarly to Hurricane Orlene, which made landfall on Oct. 3 just north of the Nayarit-Sinaloa border as a Category 1 storm before dissipating further inland. Orlene had strengthened into a Category 4 storm over open waters the day prior. — CNN