Significant Weather Blog: Thursday, December 18, 2025 11 AM

Strong, Possibly Damaging, Southerly Winds on Friday

A fast moving but vigorous weather system moving across our country’s northern tier will bring a period of heavy rain late Thursday into Friday and several hours of strong, possibly damaging winds during the day on Friday.  Localized rainfall of 1 to 2 inches is possible with some impacts to the Friday morning commute, especially in the Connecticut River Valley region.  The greater concern is for southerly wind gusts of 50 to 60 mph Friday mid-morning to mid-afternoon mainly across RI and eastern MA including the Cape and Islands.  The purpose of this update is to primarily fine tune the timing of strongest winds.

All model projections point to a southerly low-level jet of 75 to 80 knots across the Cape and Islands and adjacent eastern MA.  The core of the jet passes over the Cape but the better mixing of the winds to the surface may occur over interior portions of southeast MA.  The trickiest part of the forecast is determining how much of the low-level jet of wind will mix to the surface, a typical issue with southerly flow during the winter.  Temperatures in the upper 50s would result in enough low level instability to mix a lot of the wind one to two thousand feet aloft to the surface.  The time frame of greatest risk of strong, possibly even damaging, wind gusts for RI and eastern MA will be 9 AM to 3 or 4 PM on Friday.  For southeast MA including and especially the Cape and Islands, the peak wind will likely be observed between noon and 4 PM.  Wind gusts will likely cause some downed trees and large branches across RI and eastern MA, especially the Cape and Islands and adjacent southeast MA along and southeast of the I-95 corridor.  Anticipate scattered power outages.  Elevated and exposed locations such as the Blue Hill Observatory may experience a few wind gusts over 60 mph.

Following passage of a cold front Friday afternoon, westerly winds may gust between 40 and 50 mph throughout southern New England as colder air is ushered into the region.

This will probably be the last message on this event unless there is a significant change in severity or timing.  Check the National Weather Service webpage for the latest information on watches, warnings, and/or advisories.

A weekly significant weather update will be issued on Monday.  That message will address any significant weather that might occur during the week encompassing the Christmas holiday.

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.

A blog is issued when there is a potential risk of hazardous weather to southern New England and serves to provide background information regarding the significant weather with somewhat of an educational slant.  In the case of hurricanes, the author will attempt to issue a message when any portion of the United States coastline may be seriously impacted.  It’s intended to complement and not serve as an alternative to official forecasts issued by the National Weather Service.  Readers are urged to check National Weather Service forecasts and warnings for the most timely and updated weather information.  This weather message is solely produced by the listed author and does not constitute an official product of the Blue Hill Observatory and Science Center (BHOSC).

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.

Blue Hill Observatory and Science Center (BHOSC)

The BHOSC maintains a continuous daily observation record that dates from February 1, 1885 without interruption and provides educational information on weather and climate to area students and the community at large.  Your support of BHOSC is much appreciated and enables this nonprofit organization to maintain the long-term climate record at the Blue Hill Observatory (longest continuous record in North America) and provide valuable educational resources on weather and climate via outreach to schools, site visits/tours, webinars, and conferences.  For more information on the Blue Hill Observatory and Science Center, explore bluehill.org.

Message issued December 18, 2025 by:
Bob Thompson
Retired National Weather Service Meteorologist
Blue Hill Observatory and Science Center Board member