Tropical Atlantic Update: Erin is a large and intense hurricane, producing coastal flooding along U.S. east coast

20 August 2025

Erin is a large and intense hurricane, producing coastal flooding along U.S. east coast

Hurricane Erin has made the anticipated turn to the north and it is now centered roughly between South Carolina and Bermuda. It is an upper-end Category 2 hurricane, and a large one at that. Tropical storm force winds extend an average of 230 miles from the center, and hurricane force winds extend an average of 80 miles from the center.

To put those sizes on a map, I superimposed the latest sizes of the tropical storm (orange) and hurricane (red) wind fields on a satellite image from 5pm EDT on Wednesday:

And because of its size, tropical storm warnings are in effect for the Outer Banks of North Carolina up into the DelMarVa peninsula and there will also be noticeable and destructive storm surge and coastal flooding from South Carolina up to New York, particularly in the Outer Banks.

Erin could still briefly re-intensify to Category 3 status later today and into Thursday, then will gradually weaken over cooler water as it races off to the northeast, avoiding any direct landfalls. It will still be a formidable low pressure system when it reaches the UK in 6 days or so.

Through today, the 2025 hurricane season's ACE (Accumulated Cyclone Energy) is at 159% of an average season's value on August 20. The last years that had higher values by this date were 2024, 2008, and 2005. So not only is the ACE significantly higher than normal for the date, the season's first major hurricane formed 16 days ahead of climatology.

Erin is still an original name from the 1983 list, and it's been used every six years since then, so this is its 8th time around. It's very unlikely that the name will get retired after this incarnation, so it will be back on the list in 2031. Some of you may recall Erin 2001, which was a large intense hurricane, also sitting off the U.S. east coast. A weather satellite caught this stunning and haunting image of Hurricane Erin on the morning of September 11, 2001.

I co-authored a paper that featured this image, and it was the "Picture of the Month" in the American Meteorological Society's Monthly Weather Review journal, available here: Vortical Swirls in Hurricane Eye Clouds.

Elsewhere across the Atlantic, there are two tropical waves that could develop in the coming week. At this point, neither one appears to be a threat to land, but NHC is giving the western one (~50°W) a 60% chance and the eastern one (~30°W) a 40% chance of development. This map below shows the current infrared satellite image with tracks from the most recent American model ensemble run overlaid. It's messy, and only the western one looks like it has a shot as lasting more than a few days, although it's extremely broad and disorganized now.