Nor'easter forecast off US East Coast, with possible subtropical development

Mixed · 2Forecast models suggest a strong coastal low could develop off the US East Coast around 19–20 October and linger offshore for several days, bringing high winds, coastal flooding and dangerous surf. 1 2 Right · 1The Daily Mail, reporting on 15 October, said a cold front was forecast to push toward the Atlantic by Saturday morning. If it stalled near the Southeast coast, a storm could form over the Gulf Stream and draw heat and moisture from its warm waters. 1 Right · 1That could give the system tropical characteristics, making it a hybrid of a nor'easter and a tropical cyclone. The Daily Mail said any tropical or subtropical development would most likely come between 19 and 22 October, and that the chance remained low. 1

Centre · 1By Newsweek's report on 18 October, the National Hurricane Center said a strong non-tropical low was expected to form within a day or two. It said the low would move slowly and erratically through the middle of the following week, and that some subtropical development was possible. 2 Right · 1The Daily Mail said the European model showed the system strengthening offshore by 23–24 October, with central pressure falling from 990 to 984 millibars. It noted that these numbers alone do not establish how strong the winds would become. Models from Google DeepMind and Germany's weather service showed similar scenarios. 1 Right · 1Meteorologist David Tolleris compared the setup to the 1991 'Perfect Storm', saying 'it looks like the atmosphere is trying to do something like that again.' Meteorologist Ryan Maue wrote that a cut-off low could find enough warm water to become a subtropical or tropical storm and 'stay out to sea'. 1

Centre · 1Expected impacts depend on how close the storm tracks to shore. AccuWeather's Carl Erickson said wind gusts could reach up to 60 mph along parts of the mid-Atlantic coast. He said the most significant impacts were expected from southeastern Virginia into the Outer Banks, and that flooding could last over multiple high tides. 2 Mixed · 2AccuWeather expected strong coastal winds from North Carolina to southern New Jersey through Tuesday, with coastal flooding and beach erosion possibly lasting through Thursday. The Daily Mail reported surf of 12–25 feet offshore and heavy beach erosion expected along Florida's east coast. 2 1 Centre · 1The National Weather Service issued storm and gale warnings. On Friday, a state of emergency was declared for Hatteras Island, North Carolina, and visitors were ordered to evacuate because Highway 12 was expected to become impassable. 2

Centre · 1Newsweek placed the storm in a wider context. A similar nor'easter hit the East Coast in late September, and the Atlantic hurricane season has been below average, with nine named storms so far, largely because of a strengthening El Niño. 2 Centre · 1El Niño can suppress hurricanes through wind shear but can contribute to more nor'easters in winter. An NWS meteorologist said it was unclear how much role it played in the current storm, and Erickson said it was too early to say whether nor'easters would outnumber tropical impacts before the season ends on 30 November. The NWS Climate Prediction Center forecasts a strong-to-very strong El Niño through January–March 2027. 2