AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 131 PM EST Thu Jan 22 2026 .WHAT HAS CHANGED... Confidence continues to increase on an arctic outbreak Friday night and Saturday, followed by a high impact winter storm Sunday into Monday. Cold weather headlines and Winter Storm Watches have been issued, along with Gale Warnings and Freezing Spray headlines for the coastal waters. && .KEY MESSAGES... - Few snow or rain showers through the evening, primarily in western MA. - Dangerously cold wind chills Friday night into Saturday with heavy icing from freezing spray on the coastal waters. - A winter storm has the potential to bring substantial snow accumulations to Southern New England Sunday through much of Monday. Winter Storm Watches have been issued Sunday into Monday evening. Travel Sunday into the Monday morning commute is likely to be very difficult. && .DISCUSSION... Key Message 1...Few snow or rain showers through the evening, primarily in western MA. Weak front and mid level short wave was producing some light snow showers in western New England this afternoon. These features will weaken as they approach our area through the evening, but we could still see some light snow or rain showers (maybe more like flurries or sprinkles) with no impact given temperatures are all above freezing. Key Message 2...Dangerously cold wind chills Friday night into Saturday with heavy icing from freezing spray on the coastal waters. Arctic front still on schedule to cross southern New England Friday afternoon. It`s possible we see a few snow or rain showers ahead of it during the day, especially in western New England, but for the most part it will come through dry. Behind front, our well advertised shot of arctic air arrives on strong NW winds Fri night with core of coldest air passing over us on Saturday. Both 850 mb and 925 mb temps bottom out at -20C to -25C across southern New England which is anomalously cold (-2 to -3 standard deviations) and deep mixing will bring gusts of 35- 45 MPH per model soundings. We`ve converted the Extreme Cold Watch along east slopes of Berkshires to an Extreme Cold Warning for wind chills as low as -25F Friday night into Saturday, and we`ve issued a Cold Weather Advisory elsewhere (except for Cape Cod and Islands) for wind chills as low as -15F. Actual air temperatures will drop into the single numbers Friday night and only recover into the teens Saturday afternoon, possibly staying just below 10 degrees in the higher elevations. On the coastal waters Gale force winds of up to 40kt offshore, combined with the arctic cold, is expected to lead to moderate or even heavy freezing spray Friday night into Saturday, resulting in dangerous icing for vessels at sea. The areas of greatest concern for heavy icing is on E MA waters including Nantucket Sound. Light freezing spray should persist much of the day Saturday. Key Message 3...- A winter storm has the potential to bring substantial snow accumulations to Southern New England Sunday through much of Monday. Winter Storm Watches have been issued Sunday into Monday evening. Travel Sunday into the Monday morning commute is likely to be very difficult. A potent winter storm moving through the Southern Plains, Mid-South and the Appalachians/Mid-Atlc states late this week/early this weekend is poised to affect Southern New England Sunday, continuing into a good portion of Monday. This system is expected to carry with it a copious amount of moisture from the Gulf and the southeast Pacific - which leads to a large amount of liquid-equivalent precipitation, much of if not all of which will be falling into an antecedent, although modifying, frigid Arctic airmass. And much of if not all of precipitation is expected to fall as snow, although there are some model-forecast outcomes which show an injection of above-freezing air aloft which could tilt some areas over to sleet. There were overall no substantial change in the forecast guidance compared to previous forecasts; and it looks as though the storm`s track seems anticipated to pass eastward from the mid-Atlantic near 40N/70W. Although this is a favorable track for accumulating snow in the I-95 corridor, the deeper moisture associated with this system looks to generate a large precipitation shield. There are still plenty of uncertainties that need to be ironed out specific to the accumulations. One is the potential for heavier mesoscale banding and the placement of those snowbands, which are still uncertain at this Day-4 to Day-5 range. There is also the possible development of a warm nose aloft, solutions offered by the ECMWF and Canadian-GEM and their ensembles, which could force some areas over to sleet for a time Sunday night or into Monday and that could cut into accumulations. The greatest risk for this appears to be in southeast New England, potentially as far north as the I-95 corridor. Finally, it isn`t clear how long snow may last, with the potential for wrap- around bands of snow lingering into Monday mainly in interior Southern New England along/north and west of I-95. We continue to take a probabilistic approach weighing the above uncertainties. That being said, continued high probabilities of over 6 inches of snow and moderate probabilities of over 12 inches of snow led to issuance of a Winter Storm Watch for all of Southern New England. We are messaging the potential for snow totals in the 6 to 12 inch range being common, with the potential for over 12 inches in some locations. This could be a conservative best estimate and additional changes are likely, and there are still some forecasts which are quite a bit higher than what is stated in the Winter Storm Watch. Although in light of the above uncertainties, it seems prudent to continue to watch trends. Snow looks to begin Sunday morning, quickly becoming heavy Sunday afternoon into at least Monday morning, and while snow intensity may ease up some into Monday for eastern/southeast New England, the potential for snowbands dropping additional moderate to heavy snows may continue into Monday. Travel is likely to become very difficult and treacherous, especially for overnight and continuing through the Monday morning commute. Fortunately the chances of enhanced winds with this system and its passage Monday evening are low. That should help with recovery, but it remains quite cold behind this system, so the snow is likely to stick around into next week. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 18Z TAFs: High confidence. VFR. SW winds gust to 25kt through late afternoon, then diminish to 5-15kt tonight. W/SW winds Fri increase during the morning with 20-30kt gusts, then shift to NW later in the day with 25-35kt gusts into Fri night. KBOS Terminal...High Confidence in TAF. KBDL Terminal...High Confidence in TAF. Outlook /Friday Night through Monday/... Friday Night: VFR. Windy with gusts up to 30 kt. Saturday: VFR. Windy with local gusts up to 30 kt. Saturday Night: VFR. Breezy. Slight chance SN. Sunday: MVFR/IFR conditions possible. Breezy. SN. Sunday Night: Mainly IFR, with areas MVFR possible. Windy with local gusts up to 30 kt. SN likely. Monday: Mainly VFR, with areas IFR possible. Breezy. Chance SN. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. High confidence through the weekend. Main concern as outlined above is for Gale force NW winds and moderate to heavy freezing spray Fri night and Sat as arctic air surges into southern New England. Prior to that, gusty W/SW winds will persist through Fri with gusts of 25-30kt at times on coastal waters. Concerning winter storm for Sun into Mon, not looking at strong winds until the storm passes to our east later Mon with potential SCA winds and seas, perhaps Gales on outer waters. Certainly looking at likelihood of heavy snow with poor visibility, although there could be mixing with sleet or even rain on south coastal waters. Outlook /Friday Night through Monday/... Friday Night: Strong winds with gusts up to 35 kt. Areas of rough seas. Freezing spray, slight chance of snow. Saturday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Freezing spray. Saturday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of snow. Sunday: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Seas locally approaching 5 ft. Snow, chance of freezing spray. Visibility 1 nm or less. Sunday Night: Strong winds with gusts up to 35 kt. Seas up to 5 ft. Snow, chance of freezing spray. Visibility 1 nm or less. Monday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Seas up to 5 ft. Chance of snow, chance of freezing spray. Local visibility 1 nm or less. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...Cold Weather Advisory from 10 PM Friday to 10 AM EST Saturday for CTZ002>004. Winter Storm Watch from Sunday morning through Monday evening for CTZ002>004. MA...Cold Weather Advisory from 10 PM Friday to 10 AM EST Saturday for MAZ003>007-010>021-026. Winter Storm Watch from Sunday morning through Monday evening for MAZ002>024-026. Extreme Cold Warning from 7 PM Friday to 1 PM EST Saturday for MAZ002-008-009. RI...Cold Weather Advisory from 10 PM Friday to 10 AM EST Saturday for RIZ001>007. Winter Storm Watch from Sunday morning through Monday evening for RIZ001>008. MARINE...Gale Warning from 1 PM Friday to 7 AM EST Saturday for ANZ230>237-250-251-254>256. Freezing Spray Advisory from 10 PM Friday to 4 PM EST Saturday for ANZ230-233>235-237-256. Heavy Freezing Spray Warning from 10 PM Friday to 1 PM EST Saturday for ANZ231-232-250-251-254-255. && $$