Updated

Updated · CNN · Oct 21

Josephine Nears 74 mph Hurricane Strength as 65 mph Storm Pulls Away From East Coast

Updated

Updated · CNN · Oct 21

Josephine Nears 74 mph Hurricane Strength as 65 mph Storm Pulls Away From East Coast

Q: Why might an offshore hybrid storm like Josephine pose a greater coastal flooding threat than a traditional hurricane?

An offshore hybrid storm like Josephine can pose a greater coastal flooding threat because its strongest winds often spread much farther from the center and last longer over a broad stretch of ocean than in a compact, traditional hurricane. That wider wind field matters because coastal flooding is driven less by the storm’s label than by how much water the wind pushes toward shore. Subtropical and transitioning extratropical systems often behave more like nor’easters, with persistent onshore winds acting over a long fetch. That allows waves and water levels to build for many hours or even days, even if the storm’s core stays well offshore. Josephine fit that pattern. Forecasts said tropical-storm-force winds extended hundreds of miles from the center, with large swells, dangerous surf, beach erosion and flooding possible from the Mid-Atlantic to Cape Cod despite most rain and strongest core winds remaining at sea. Reports also showed flooding tied to repeated high-tide cycles, including Outer Banks overwash and damage to N.C. 12. A traditional hurricane can produce extreme surge near and just to the right of landfall, but its worst coastal flooding is often concentrated in a narrower zone. A hybrid storm offshore may generate lower peak surge than a major landfalling hurricane, yet still create a broader, longer-duration flooding problem because of its size, prolonged onshore flow, and overlap with astronomical high tides.

3 articles · Updated · CNN · Oct 21

Josephine was 195 miles southeast of Nantucket on Thursday morning with 65 mph sustained winds, accelerating eastward away from the Eastern Seaboard.
Forecasters expect some strengthening over the next day, with the subtropical storm potentially reaching Category 1 hurricane-force winds by late Thursday before turning post-tropical farther out at sea.
Cape Cod faces the strongest onshore effects, with breezy to windy conditions lingering through Thursday and coastal flooding possible at high tide from the Mid-Atlantic to Cape Cod through Friday.
Most of Josephine's rain and wind should stay over the open Atlantic, leaving much of the East Coast dry into the weekend.
Josephine is the Atlantic season's 10th named storm, forming later than the usual late-September pace as El Niño has suppressed activity.