Large Erin Pulling Away from the U.S. but Coastal Issues Linger
Coastal flooding will plague parts of the mid-Atlantic again Friday as life-threatening rip currents persist into the weekend
Hurricane Erin passed to within about 250 miles of North Carolina’s Outer Banks Thursday morning at it closest point of approach to the U.S., with its extraordinarily large wind field bringing wind gusts as high as 49 mph to the coast and widespread areas of moderate to even major coastal flooding.
The breadth of Erin’s tropical storm winds stretched 700 miles across the western Atlantic Friday morning as it began its transition into a powerful extratropical storm. Of the nearly 350 Atlantic hurricanes over the past 60 years, fewer than 15 ever grew as large as Erin, putting Erin in the top 4% of Atlantic hurricanes in terms of its size.
Other than Superstorm Sandy in 2012, no other hurricane as large as Erin in the satellite era (since 1966) has tracked as close or closer to the U.S. east coast.
By early Thursday, Erin’s tropical storm winds stretched from the southeastern shores of Cape Cod all the way to Bermuda.
Coastal concerns persist into the weekend
Erin’s wide winds and large waves brought widespread moderate flooding and pockets of major coastal flooding from North Carolina to parts of the Mid-Atlantic on Thursday.
The observed flooding generally topped out at around 3 feet above ground in most places, with flooding worsened at the open coastline by runup from breaking waves. The type of coastal flooding observed, while significant, would be characterized as a 1 in 10 year flood event, according to long-term records at these flood gauges.
It's worth reiterating how fortunate the U.S. was to have dodged the worst of Erin, an exceptionally large and powerful hurricane that would’ve delivered a far more serious blow had the track been just a few hundred miles farther west.
Though the worst is behind, we can expect another round of coastal flooding during the times of high tide today before water levels begin to subside into the weekend.
Even though Erin will be transitioning into an extratropical storm and quickly accelerating out to sea today and Saturday, dangerous and life-threatening rip currents will persist along most east coast beach through the weekend in its wake, so beachgoers are advised to stay out of the water.
Invests 99L and 90L could develop but models divided on their future
We continue to track two disturbances over the open Atlantic today, although both systems remain starved of organized storminess.
The candidate most likely to develop in the coming days in Invest 90L north of the northeastern Caribbean islands. Intensity guidance does show 90L gradually organizing in the coming days, but most reliable models advertise only modest strengthening to a tropical storm or at most borderline hurricane.
The American GFS is more bullish on development than its European counterpart and for now both models show the system remaining small, unlike Erin. Track guidance has 90L or what forms of it curving near or east of Bermuda early next week, but it will not pose a threat to the U.S.
Meanwhile a tropical wave in the deep tropical Atlantic – Invest 99L – will be moving due west into next week, but models remain tepid at best on long-term prospects. It’s possible conditions become a little more conducive to development later next week when it’s in the Caribbean but none of our models are keen on developing it for now and it should continue westward toward Central America regardless.
I am REALLY hoping that whatever that edgy 99L does, it dissipates as a wave over Central America 👈🏻