Roslyn Rapidly Strengthens in the Eastern Pacific, Nearing Western Mexico

Pipsqueak 94L in the central Atlantic poses no threat

The eastern Pacific continues to churn up strong hurricanes, including its fourth major (Category 3 or stronger) storm of the season that formed overnight and is expected to strike western Mexico in the next 24 hours.

Hurricane Roslyn rapidly strengthened from a tropical storm early yesterday to a high-end 125 mph Category 3 hurricane this morning. Roslyn’s rate of strengthening – nearly 65 mph in 24 hours – is impressive and bested or tied by Hurricanes Orlene and Darby earlier this year. Only about 0.6% of all tropical or subtropical cyclone “fixes” (6-hourly storm intensity estimates) in the eastern Pacific exhibit such rapid intensification. Before Darby in July, we have to go back to Kiko in September of 2019 to find a storm in the eastern Pacific to strengthen so quickly.

Roslyn is forecast to strengthen further today into a Category 4 hurricane as it heads toward the states of Jalisco and Nayarit in western Mexico. While wind shear is forecast to pick up as it nears the coastline tonight and early Sunday, it likely won’t have time to weaken appreciably before coming ashore overnight. Roslyn poses a serious threat to not only the coast but to mountainous areas inland, where torrential rainfall could lead to widespread flash flooding and landslides.

Meanwhile in the Atlantic, things remain quiet. NHC is highlighting a non-tropical low-pressure area sprung from an old stationary front in the central Atlantic. The small but defined area of spin, which they’ve designated Invest 94L, is struggling to maintain organized thunderstorms as it zips westward over open waters.

The system has only a low chance of forming in the next day or two before increasingly hostile upper-level winds close the narrow development window. Regardless of development, 94L poses no threat to land.