Significant Weather Blog: Tuesday, December 23, 2025 8 AM

Significant Weather Outlook for the Coming Week – Updated

Less Snow Now Expected for Today/Tonight

Winter Weather Possible Late Friday/Saturday but High Uncertainty

Today/Tonight Although only light snow was expected anyway today/tonight, it looks like the precipitation will be lighter still with likely more rain mixed in. Although there is a possibility that light rain or rain/snow mixture may change to a period of some snow accumulation tonight in eastern MA as surface low pressure forms east of Cape Cod, it’s uncertain if the boundary layer can cool fast enough for the precipitation change (especially south of Boston). It now looks like total snow accumulation will be only a coating to an inch or so across most of southern New England with possibly 2 to 3 inches along and north of the route 2 corridor and over the higher elevations of the Berkshires. For white Christmas enthusiasts, there is a fairly high probability of it over the northern Worcester Hills and the Berkshires. Elsewhere in southern New England, a white Christmas is still possible but looking less likely. Travel impacts are likely to be minimal today as what snow does fall will probably struggle to stick on pavement. An exception could be the Berkshires and the northern Worcester Hill (along and north of route 2) where there could be some slick roads later today and tonight. Light snow will overspread southern New England mid-morning to midday as warmer air overrides a lower layer of colder denser air. The warm front will likely slow or stall due to northwest flow aloft. A surface low pressure area moves toward northern New England (not typically a favorable track for snow in southern New England) but then redevelops southeast of New England before moving offshore. The snow will likely mix with or change to light rain over much of the area along and south the Mass Pike this afternoon as some warmer air is drawn into the area from the south or southeast (aided by mild ocean temperatures well into the 40s). The precipitation may change back to snow across eastern MA tonight as weak surface low pressure develops east of Cape Cod with possible light accumulations (inch or less). There is a slight possibility that there could be a burst of 1 to 2 inches of snow tonight over northeast MA but this looks to be uncertain. Updated snowfall forecasts:

Along and north of route 2 and over the Berkshires: 2 to 3 inches
Mass Pike (I-90) to route 2: Around an inch
South of the Mass Pike (I-90): Coating to an inch

Mid Week Holiday Travel For the most part, fairly benign weather is expected for Christmas Eve and Christmas Day with the possible exception of a few light snow or mixed rain/snow showers on the Cape Wednesday morning. For most of southern New England, no travel impacts are anticipated those two days. An exception to benign travel weather is expected over much of California for the upcoming holiday period when heavy rain (with flooding) is expected at lower elevations and heavy snow (being measured in feet) is anticipated for the higher elevations. A robust atmospheric river is expected to persist/intensify over that region. Anyone traveling to the west coast, especially California, should check latest forecasts and adjust travel plans if necessary. Late Friday into Saturday The weather outlook for Friday/Saturday is somewhat interesting and quite uncertain. Upper level energy and a fairly weak surface low pressure area but with moderate amounts of moisture will travel along a low level thermal boundary late Friday into Saturday morning. Computer models have been widely variant on just where this low level thermal boundary sets up and where significant wintry precipitation could fall. For example, the Canadian and UKMET operational models depict a moderate snowstorm across northern New England extending into northern MA, the ECMWF depicts a moderate snowstorm over southwest CT and the greater NYC area, and the overnight GFS depicted a rather robust snowstorm for the Washington, DC area, keeping southern New England dry! The latest GFS run is further north with the heaviest snow between Philadelphia and New York City. The tendency has been for a colder solution given a fairly strong high pressure center passing across Quebec (many earlier model runs projected mostly rain across southern New England). The other potential twist is that there could be shallow cold air overrun by enough warmer air to set up a potential ice scenario. We will need to evaluate future model runs and trends. Taking latest trends and a consensus of recent model runs, am thinking there will be enough deep cold air and enough moisture for a light to moderate snowfall across much of southern New England late Friday into Saturday. Will provide an updated message blog later in the week if there should be an increased risk for a significant winter weather event for southern New England. Late in the Weekend Finally, still another system may cross the area late Sunday/Sunday night. This is quite far out and the precipitation type (rain or snow?) and amount are very uncertain. 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 bluehillobservatory.org. Message issued December 23, 2025 by: Bob Thompson Retired National Weather Service Meteorologist Blue Hill Observatory and Science Center Board member