Significant Weather Outlook: Monday, January 12, 2026 5 PM
Weekly Significant Weather Outlook
The large scale mid tropospheric weather pattern for the week ahead favors the evolution of a fairly high amplitude ridge in western North America and a fairly high amplitude trough in eastern North America by later in the week. This is sometimes referred to as a positive Pacific North America (+PNA) index. Such a pattern tends to favor colder temperatures in the eastern U.S. and milder in the western U.S. It can also set the stage for a potential winter storm or two in the east depending upon other details. The global atmospheric models depict a series of “short wave” troughs (shorter period waves embedded in the larger scale flow) that flow through the quasi-stationary “long wave” trough in eastern North America. The various models have shown considerable inconsistency among each other and from one run to the next in the handling of these short wave troughs. This is evident in a large spread among each model’s ensemble members (slight changes to the initial conditions result in markedly different solutions). The latest trends seem to deemphasize the chances of a coastal low formation, although we’re still 4 or 5 days out.
More specifically, one of those “short wave” upper troughs and associated cold front may produce a few snow or mixed rain/snow showers mid week. A few operational and ensemble runs had also been depicting the development of a coastal storm in the Thursday night to Friday time frame, while the majority of model runs show a weaker pulse of energy that doesn’t really show development until the system reaches the Canadian Maritimes – a scenario we’ve seen before this winter. And latest trends today seem to deemphasize the chances of a coastal surface low formation with one weak system passing north of southern New England and another far to the south. It appears that the upper-level energy embedded in the polar jet stream may not be strong enough to “dig” south enough to trigger strong baroclinic development (i.e., take advantage of the potential energy contained in a low-level temperature gradient typically resident off the U.S. east coast during winter) south of New England. Thus, while remaining a possibility, a coastal storm Thursday night into Friday is presently looking like an increasingly remote chance.
There looks to be an additional pulse of short wave energy that could produce some precipitation later in the coming holiday weekend – perhaps sometime in the Sunday to Monday time frame. This, too, looks nebulous.
The only conclusion at this time is that the weather should turn somewhat colder late in the week, and there is a potential for at least some snow late in the week and/or over the weekend. The odds currently favor only light amounts of snow despite a large scale upper level pattern change that would seem to favor potential winter weather.
If later trends depict a potentially more significant storm development, then a series of message blogs will be started. Otherwise, the next weekly significant weather update will be provided on Monday January 19.
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 January 12, 2026 by:
Bob Thompson
Retired National Weather Service Meteorologist
Blue Hill Observatory and Science Center Board member
