High Impact Nor’easter Friday through Sunday
A large and strong nor’easter has begun to develop off the mid-Atlantic coast and will impact southern New England mainly in the Friday through Sunday timeframe. There’s little doubt that this will be a slow-moving/long duration storm, which will exacerbate the various impacts. Impacts from this storm will include very rough seas, shoreline erosion, coastal flooding, strong winds, and swaths of heavy rain. There remains some uncertainty in magnitude and timing of greatest impacts, although the probability of a generally impactful storm is high especially along/near coastal areas.
Synoptic Set-up
There has been a gradual convergence in the model solutions but still some notable differences in track and timing details. The ECMWF and to a somewhat lesser extent UKMET are further west than the GFS, NAM, and Canadian deterministic models. The Canadian model has faster timing than the other models. The ensembles show less spread but still enough to influence the magnitude and location of impacts. A consensus track brings the surface low center slowly north to a position south of Nantucket and then retrogrades west some before eventually pulling off to the northeast (Sunday night or Monday depending upon the model). The pressure gradient between the high pressure center to our north over Quebec and the low center to our south will generate strong northeasterly winds. All models depict a large storm with a broad swath of gale to storm force winds to the north and northwest of the low center.
Although there will be effects sooner and later, the most significant impacts are anticipated Friday to Sunday in terms of winds, coastal erosion and flooding, and heavy rain bands. The strongest winds and heaviest rain are anticipated to be across eastern MA and southern RI but with the potential for significant wind and rain across central MA and both eastern and southern CT depending upon the storm’s eventual track.
The following sections will describe in more detail the anticipated impacts for southern New England.
Marine
Small craft operators are recommended to remain in port with secure moorings through Sunday. Winds will increase and seas will build Thursday and make for increasingly hazardous marine operations by late Thursday or Thursday night. Sustained gale force winds with potentially storm force gusts are expected to develop Friday, continue through Saturday and possibly persist into Sunday. Seas will likely build to between 18 and 25 feet in the coastal waters and possibly as high as 20 to 30+ feet a little further offshore. The large envelope, long fetch, and long duration of strong winds will allow seas to build to dangerous heights.
This storm may interrupt ferry service to/from Nantucket, Martha’s Vineyard, and Block Island Friday and Saturday, if not even into Sunday.
Coastal Impacts
Areas of severe beach erosion are likely to develop Friday through Sunday along exposed east facing shorelines due to large waves atop elevated water levels crashing onshore over multiple high tide cycles. Even south facing shorelines of MA and RI will be susceptible to beach erosion as large swells come ashore. Given the long duration of this event, anticipate wave periods to increase. Our experience is that waves with longer periods tend to contain more energy and can have a greater erosion impact.
The coastal flooding forecast is somewhat tricky. Anticipate the storm surge to increase to 2 to 3 feet along much of the MA east coast, although cannot completely rule out a period of 3 to 4 feet surge. The astronomical high tide is increasing over the weekend (due to the combined gravitational pull of the moon and sun during/near the time of a full moon), although the highest astronomical tides don’t occur until early next week. The projected surge on top of the predicted astronomical high tide would lead one to expect minor to perhaps approaching moderate coastal flooding. However, a more significant impact may occur due to the runup and overwash from large waves being driven onto the shore. Am also a little leery of the long duration that will span multiple high tide cycles as well as the potential for the storm to retrograde toward our shoreline. Thus, would advise coastal interests to prepare for at least moderate coastal flooding. Along those shorelines especially vulnerable to wave action, there could be at least a low risk of some damage to decks, docks, etc. Coastal residents and visitors are advised to monitor the latest forecasts and any warnings from the National Weather Service.
Although the focus of this blog is on southern New England, the potential for severe beach erosion and moderate coastal flooding also exists for Long Island (as well as portions further south along the mid-Atlantic coastline – perhaps even as far south as North Carolina).
Wind
There is a risk of damaging northeast winds, especially along/near the MA and RI coast. Preliminary peak wind gust estimates are: 50 to 60 mph over the Cape and Islands, south coastal RI, as well as outer Cape Ann, 40 to 50 mph along the rest of eastern MA, much of RI, and coastal CT, and 30 to 40 mph across central MA and eastern/interior southern CT. The period of strongest winds looks to be Friday afternoon through Saturday night, although a few models keep fairly strong winds lingering into Sunday. An important factor to keep in mind is that trees are fully leafed out and that increases the risk of downed trees and branches as well as associated power disruptions. In fact, the National Weather Service notes from experience that wind gusts of 40 to 45 mph are high enough to bring down branches and cause some power interruptions.
Rain
Total storm rainfall may reach 2 to 4 inches across much of eastern MA and RI and 1 to 3 inches across central MA and eastern/southern portions of CT. Lesser amounts are anticipated further to the west. Since this rain will occur over a relatively long duration, the risk of flooding is low except in some prone urban and poor drainage areas should heavier bands of rain pass through.
Tropics
Whereas the Atlantic Basin continues to be relatively quiet with respect to tropical cyclone activity, the eastern North Pacific remains very active. Major Hurricane Polo is moving northwest parallel and somewhat offshore of the Mexican coast. Although there is considerable uncertainty, Polo may approach Baja California in a few days. Regardless of its exact track, Polo has and will continue to help shunt moisture into the southwest U.S. monsoon and keep an elevated flash flood risk for portions of the southwest U.S.
Further west, a tropical depression has formed and will likely intensify into a hurricane, if not a major hurricane, as it moves toward the Big Island of Hawaii. Although steering currents will likely cause the hurricane to turn sharply west before reaching the coast of Hawaii, it will pass close enough to likely cause extremely heavy rain, flash flooding, and mudslides on the Big Island in the coming days.
Next Message
Another weather blog message will be issued Thursday (probably late morning or midday) for this early season nor’easter.
About this Blog and Disclaimer
The National Weather Service monitors the weather 24/7 and updates forecasts, watches, and warnings as necessary. For most of southern New England, refer to your local Weather Forecast Office for the latest forecast/warning information at weather.gov/box. For information from other Weather Forecast Offices, go to weather.gov and click on the location of interest on the map.
The frequency of this blog will depend upon the nature of the weather threat and availability of the author. Thus, for the latest information on weather forecasts and warnings, refer to the National Weather Service, which monitors and forecasts the weather 24/7.
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Message issued September 23, 2026 by:
Bob Thompson
Retired National Weather Service Meteorologist
