Hurricane warnings are in effect from Playa Perola to El Robleto, including Puerto Vallarta, a popular vacation destination. Las Islas Marías, a group of scattered islands off the coast, is also in the warning area. To the north of the warning zone, a hurricane watch extends all the way to Mazatlan, while tropical storm watches cover that area and the area south of the hurricane warning to Manzanillo.
Chances are increasing that the storm could come ashore as the strongest to hit that area since Storm Kina in 2002, which made landfall at the mouth of the Rio Grande de Santiago near Boca de Asadero as a Category 4 hurricane with winds of 140 mph. It was a Category 5 storm just 10 hours before making landfall.
Rosslyn Rapid Condensation
Roslin appeared after a group of thunderstorms off the west coast of Mexico turned into a tropical depression and eventually storm Thursday. It wasn’t until 11 p.m. ET on Friday when Rosslyn became a hurricane, but it quickly intensified into a major hurricane, known as Category 3 or higher, Saturday morning, just six hours later.
Rapid intensification, defined as a rise of 35 mph or more in the storm’s maximum sustained winds within 24 hours, is likely in the presence of warmer waters and calm winds at the upper level. There are emerging links between human-induced climate change and the frequency and intensity of rapid intensification.
How fast climate change is fueling super tornadoes
By mid-morning ET on Saturday, Roslin had winds of 120 mph and was just over 150 miles southwest of Manzanillo, Mexico. At the time, it was moving northwest at 7 mph, but it was starting a curve to the north-northeast. It will be directed to the west coast of Mexico where it begins to feel the effects of the approach of the short-wave trough, or a pocket of cold air, low pressure and high circulation near the Baja Peninsula.
Roslin’s expected effect
On her current trajectory, Roslin is looking to make landfall in the same area that Kenna did. That would put the coastal Narrait countryside in line to experience the eye wall, or a ring of gale-force winds surrounding a placid eye. Although Rosslyn will gradually weaken, wind gusts near 120 mph are still possible on the immediate shoreline. Communities including San Blas, Matchin, and Atticama may experience the strongest winds. The winds will drastically fall outside the eyewall, but buffets with the strength of tropical storms can still be provided as far south as Puerto Vallarta.
The largest eruption will occur just south of where Roslin’s center makes landfall. That’s because the storm, like all large-scale low pressure systems in the Northern Hemisphere, rotates counterclockwise. This means that the winds south of Al Ain will be directed towards the shore. This will efficiently push the water towards the coast.
The National Hurricane Center writes that “serious storms are expected to result in significant coastal flooding near and to the east as the center makes landfall.”
The agency also warns of “large destructive waves” near the coast, which computer models suggest could be close to 25 feet in height.
Storm risk is generally lower on the west coast of Mexico than on the Gulf coast because the slope of the continental shelf is steeper on the west coast. Without the help of the gently sloping sea floor found in the bay, a storm on the Pacific side is less able to push large amounts of water up to the coast.
The storm is also expected to produce 4 to 6 inches of rain, with a maximum of about 8 inches, along the upper coast of Colima and Jalisco, southeast of Sinaloa and west of Nayarit, including Las Islas Marias.
The hurricane center wrote that “rainfall may lead to flooding and landslides in rough terrain.”