AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 626 AM EST Sat Jan 17 2026 .WHAT HAS CHANGED... Winter weather advisory remains in effect for the interior high terrain through this afternoon with just some minor tweaks to the snowfall forecast. Still some uncertainty on the northwest extent of the main snow shield later Sunday into Sunday night...but current guidance indicates an inch or two for interior southern New England with 2-4" across parts of eastern Massachusetts and Rhode Island. No other significant changes have been made. && .KEY MESSAGES... - 1-4 inches of snow is expected through this afternoon across interior northern and western MA and NW CT, with localized amounts up to 5 inches in the Berkshires. - Low pressure may bring 1-2" of snow across interior SNE later Sun into Sun night with 2-4" across parts of eastern MA/RI. Northwest extent of main snow shield remains uncertain... so these amounts may need to be adjusted. Main impacts to travel will be late Sun afternoon and evening. - Arctic cold front pushes through Monday night bringing well below normal temperatures and bitterly cold wind chills & temps. The peak of the cold weather will be Tue into early Wed morning. - Milder temps arrive later Wed-Thu with perhaps a brief period of light snow showers or even light rain showers near the coast. && .DISCUSSION... KEY MESSAGE 1... Widespread light snow event for the interior with 1- 4 inches expected. Still continuing to monitor the chance for up to 5 inches in the Berkshires. Main forcing will come from a couple of shortwaves embedded within an approaching upper level trough. First of the two arrives early this morning and the second during the early to mid afternoon. Additionally, a 30-40 kt southwesterly low level jet will bring increasing moisture into the region with a pronounced mid level boundary developing across western New Eng. Greatest swath of QPF will be from western CT to Northwestern MA where the greatest mid level frontogenesis and deep moisture will linger the longest. Will be a somewhat dynamic system as we will briefly have the left exit region of the upper jet on enhance lift across the region. Band of light snow will initially be focused mainly NW of HFD-ORH-FIT. Steadiest snow shifts NW through the morning and becomes more focused over western MA. Then, the precipitation axis will shift back south and east through CT and central as the boundary moves SE. Looking at mostly rain in these locations as temps warm into the upper 30s to low 40s. Rain may briefly flip to snow before ending near and NW of I-95 corridor late afternoon but no accumulation expected along and south and east of I-95. Snowfall rates will be mostly light through the majority of the event except for a brief period this afternoon. BUFKIT model soundings show omega values of 10-15 ubar/sec in the DGZ along the boundary as it moves SE. Could see a brief period of moderate to heavy snow with rates up to 0.5"/hr along this feature, mainly across north central Massachusetts. Southeast of I-95, higher precipitation rates may be enough to flip rain showers to a brief period of light snow with slushy coatings possible. While 00z guidance has brought 0.05-0.10" less QPF, still expecting accumulations to be mainly confined to NW of BDL-ORH-FIT where 1-4 inches is expected. The heaviest accums will likely be found in the Berkshires where locally up to 5 inches is possible, especially in western Franklin county. Little or no accums are expected across eastern MA, RI into eastern CT. Winter weather advisories are in effect from western MA into the Worcester Hills. Biggest impacts to travel will be across the Berkshires and Worcester hills. Lesser impacts expected in low elevations where temps a bit above freezing will limit accums on roads. Precip ends in eastern New Eng by early this evening with dry weather tonight ahead of next system approaching from the south. KEY MESSAGE 2...Low pressure may bring 1-2" of snow across interior SNE later Sun into Sun night with 2-4" across parts of eastern MA/RI. Northwest extent of main snow shield remains uncertain...so these amounts may need to be adjusted. The main forecast challenge continues to revolve around the northwest extent of the steady snow shield later Sun into Sun night. Low pressure will be passing to the southeast of the Benchmark...which is too far away from us to bring us a major winter storm. Nonetheless..shortwave energy hanging back to our west will pull some of the forcing/moisture northwest into our region. While the models have come into better agreement over the past 24 hours...there are still differences that would make a considerable difference in snow amounts and the northwest extent of them. A lot will be determined on how much that main shortwave can dig and result in a backed upper level flow. There are also some timing differences among the models. While areas of light snow may develop later Sunday morning into Sunday afternoon...appears the bulk of the steady snow will be late Sunday afternoon and night. Temps also may be near or above freezing in spots during the day Sunday...so we expect the bulk of the travel issues to develop later Sunday afternoon and evening. Currently...our best estimates on snowfall are an inch or two possible across the interior with 2-4" possible across parts of RI/eastern MA. Now if the track ends up on the western edge of the guidance...we may see 2-4" of snow well back into the interior with a swath of 3-6" across RI/SE MA. If the track were to end up on the eastern side of the guidance...snow accumulations would be little if any snow across interior southern New England and just an inch or two across RI/SE MA. So in a nutshell...currently our best estimate is an inch or two possible across the interior with 2-4" across parts of RI/SE MA. Steady snow should wind down after midnight. KEY MESSAGE 3...Arctic cold front pushes through Monday night bringing well below normal temperatures and bitterly cold wind chills & temps. The peak of the cold weather will be Tue into early Wed morning. The models are still in very good agreement in an arctic cold front crossing the region Mon night. This will bring a shot of arctic air and well below normal temperatures to the region. 850T will drop to between -18C and -20C with the cold peaking Tue into early Wed. Gusty west winds will result in wind chills below zero to the single digits. High temps Tue will only be in the upper teens and 20s with low temps Tue night mainly in the single digits to the lower teens. This shot of arctic air will be short-lived as high pressure shifts to our east. We should see high temps recover into the upper 20s and lower 30s by Wed afternoon...which is still below normal of this time of year. KEY MESSAGE 4...Milder temps arrive later Wed-Thu with perhaps a brief period of light snow showers or even light rain showers near the coast. High pressure moving further east and away from the mid-Atlantic coast coupled with low pressure tracking across Quebec will result in much milder air working back into the region. We may see a period of light snow showers in the warm air advection pattern and perhaps even light rain showers near the coast as the boundary layer warms. Regardless...these rain/snow showers will likely be short-lived and not expecting a significant precipitation event. Near or below normal temps may return by Fri behind this cold front. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 12z TAF Update... Today...Moderate confidence. MVFR to IFR conditions at times across the interior...while eastern MA/RI will be VFR into early afternoon before MVFR conditions arrive. Periods of snow across interior southern New England into the afternoon will transition to more rain in the lower elevations...but remain snow in the high terrain. Temps rising above freezing should alleviate any issues on runways in lower elevations by lunch time. Meanwhile...across eastern MA and RI much of the day will be dry outside a few rain showers especially late in the day. S-SW 5 to 15 knots with some gusts around 25 knots. Tonight...Moderate confidence. Some lingering MVFR to localized IFR conditions mainly across RI/SE MA along with LLWS this evening should improve to VFR. LLWS should also dissipate. Otherwise...generally VFR conditions tonight. KBOS Terminal...High confidence in TAF. KBDL Terminal...Moderate confidence in TAF. VFR through 08z-10z, moderate confidence in lower ceilings early Saturday morning with periods of -SHSN, better confidence in a period of -SN after 18z Saturday through 22z. Outlook /Sunday through Wednesday/... Sunday: Mainly VFR, with local MVFR possible. Chance SN. Sunday Night: Mainly VFR, with local IFR possible. SN. Martin Luther King Jr Day through Monday Night: VFR. Windy with areas of gusts up to 30 kt. Tuesday through Tuesday Night: VFR. Breezy. Wednesday: VFR. Windy with local gusts up to 30 kt. && .MARINE... Today and tonight...High Confidence. A period of gusty S-SW winds will develop this afternoon as a low level jet moves into the region with gusts to 25+ kt, then diminishing tonight. Seas will gradually subside tonight to 4-6 ft over outer waters. Outlook /Sunday through Wednesday/... Sunday: Winds less than 25 kt. Areas of seas approaching 5 ft. Snow. Sunday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Snow. Local visibility 1 to 3 nm. Martin Luther King Jr Day: Low risk for gale force winds with gusts up to 35 kt. Areas of rough seas. Monday Night: Low risk for gale force winds with gusts up to 35 kt. Rough seas up to 12 ft. Freezing spray. Tuesday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Freezing spray. Tuesday Night: Moderate risk for Small Craft Advisory winds with local gusts up to 30 kt. Areas of rough seas. Freezing spray. Wednesday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Seas up to 5 ft. Freezing spray. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...Winter Weather Advisory until 5 PM EST this afternoon for MAZ002>004-008>010. RI...None. MARINE...Small Craft Advisory until 7 PM EST this evening for ANZ250. Small Craft Advisory until 7 PM EST Sunday for ANZ254>256. && $$