After explosive intensification, Erin reaches rare Category 5 status

Friday night into Saturday morning was quite eventful for Hurricane Erin. In just over one day, from Friday morning at 8am to Saturday morning at 11am, the peak winds increased from 70 mph (tropical storm) to 160 mph (Category 5 hurricane).  It was in an environment with very low wind shear and warm water, and something just clicked for it.  Thankfully, it did this over open ocean and did not threaten land. This image is from its peak intensity on Saturday afternoon when the central pressure bottomed out at 915 millibars.

In the official records which date back to 1851, there have been just 42 Category 5 hurricanes in the Atlantic, so it is indeed a very rare status to reach. Erin is now the 43rd.  Michael Lowry pointed out on Bluesky that Erin is also the earliest Category 5 on record outside of the Caribbean Sea and Gulf of Mexico.

Since that peak, it has undergone a couple eyewall replacement cycles, a very normal process for intense hurricanes. During these replacements, the peak winds decrease but the size of the wind field expands. So Erin isn't a Category 5 hurricane anymore (presently Category 3 and re-intensifying as of Sunday evening), but it is larger. This satellite loop below is from Sunday evening. Outer rainbands are impacting Puerto Rico, Dominican Republic, Haiti, and the Turks & Caicos, but no land will experience the eyewall.

I have also had radar loops from Saint Maarten, Puerto Rico, and the Dominican Republic to cover Erin's progress at the usual spot: https://bmcnoldy.earth.miami.edu/tropics/radar/

Erin is forecast to track northwest then north, sliding between the U.S. east coast and Bermuda this week. It should maintain major hurricane status (Category 3+) for at least the next three days, then it will weaken slightly as it encounters cooler water and stronger wind shear north of Bermuda. This map shows the forecast probability of tropical storm force winds and their most likely arrival time.

In terms of Accumulated Cyclone Energy (ACE), the 2025 season just surpassed 100% of an average season today for the first time all year. As of the end of Sunday, it's now at 110% of average for the date.  The coming days will boost that even more.

Looking much further east, there's a broad African easterly wave located just west of Cabo Verde (the one I referred to at the end of Friday's post) that is gaining support among the global models for eventual development as it makes its way westward across the deep tropics. This is the next feature to watch closely in the coming days as there's a hint among the models that it might make it pretty far west. I suspect it will be tagged as an Invest in the coming couple of days, and it would be Invest 99L. That designation triggers the regional hurricane models to run on it.

The next name on this year's list is Fernand.

• Visit the Tropical Atlantic Headquarters.
• Subscribe to get these updates emailed to you.
• Follow me on Bluesky