Roslyn Rapidly Intensifies to a Major Hurricane

Hurricane Roslyn rapidly intensified to a major hurricane over the Eastern North Pacific Ocean near the west coast of Mexico during Friday night. At 8:00 a.m. EDT on Saturday the center of Hurricane Roslyn was located at latitude 17.6°N and longitude 106.3°W which put it about 200 miles (320 km) south-southwest of Cabo Corrientes, Mexico. Roslyn was moving toward the northwest at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 150 m.p.h. (240 km/h). The minimum surface pressure was 960 mb.

A Hurricane Warning was in effect for Las Islas Marias. A Hurricane Warning was also in effect for the portion of the coast from Playa Perula to El Roblito, Mexico. The Hurricane Warning included Puerto Vallarta. A Hurricane Watch was in effect for the portion of the coast from El Roblito to Mazatlan, Mexico. Tropical Storm Warnings were in effect for the portions of the coast from Manzanillo to Playa Perula, Mexico and from El Roblito to Mazatlan, Mexico.

Hurricane Roslyn rapidly intensified to a major hurricane during Friday night. A circular eye with a diameter of 12 miles (19 km) was at the center of Roslyn’s circulation. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Hurricane Roslyn. Storms near the core generated upper level divergence that pumped mass away from the hurricane.

The circulation around Hurricane Roslyn was small. Winds to hurricane force extended out 25 miles (40 km) from the center of Roslyn’s circulation. Winds to tropical storm force extended out 80 miles from the center of circulation. The Hurricane Intensity Index (HII) was 22.1. The Hurricane Size Index (HSI) was 7.0 and the Hurricane Wind Intensity Size Index (HWISI) was 29.1. Hurricane Roslyn was capable of causing localized major damage.

Hurricane Roslyn will move through an environment favorable for intensification during the next 12 hours. Roslyn will move over water where the Sea Surface Temperatures are near 29˚C. It will move under the axis on an upper level ridge over the Eastern North Pacific. The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear. Hurricane Roslyn is likely to intensify during the next 12 hours. Roslyn could intensify rapidly for a few more hours. Hurricane Roslyn could strengthen to a Category 4 hurricane on the Saffir-Simpson Scale. An upper level trough west of Baja California will produce southwesterly winds on Saturday night that will blow toward the top of Roslyn’s circulation. Those winds will cause the wind shear to increase. Hurricane Roslyn could start to weaken when the wind shear increases.

Hurricane Roslyn will move around the western side of a surface high pressure system centered over northern Mexico during the next 12 hours. The high pressure system will steer Roslyn toward the north. The upper level trough west of Baja California will steer Hurricane Roslyn toward the northeast on Saturday night and Sunday. The center of Roslyn is likely to pass just to the west of Cabo Corrientes during Friday night. On its anticipated track Hurricane Roslyn could make landfall on the west coast of Mexico near San Blas on Sunday morning. Roslyn will bring strong gusty winds and locally heavy rain to Nayarit. Heavy rain could cause flash floods in some locations. Hurricane Roslyn could cause a storm surge of up to 13 feet (4 meters) along the coast. Hurricane Roslyn will be capable of causing localized major damage.