AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 1209 AM EST Sat Jan 17 2026 .WHAT HAS CHANGED... Snowfall amounts were increased across portions of interior northern and western MA where winter weather advisories have been issued. Confidence is increasing in at least a plowable snowfall for portions of SNE, especially across SE MA and Cape Cod, but the westward extent of the heavier snow remains uncertain. We continue to have high confidence in a shot of arctic air Monday night into Tuesday night with bitterly cold wind chills. && .KEY MESSAGES... - 1-4 inches of snow is expected late tonight into Saturday across interior northern and western MA and NW CT, with localized amounts up to 6 inches in the Berkshires. - Offshore low pressure system may bring plowable snow to portions of the region Sunday and Sunday night. The track and westward extent remains uncertain leading to a larger range in potential snow totals at this time. - Arctic cold front pushes through Monday night bringing well below normal temperatures and bitterly cold wind chills with the coldest temperatures felt Tuesday. Gale force winds and freezing spray for the waters into Wednesday - Slightly warmer temperatures arrive by later Wednesday with a period of snow possible late Wednesday into Thursday. && .DISCUSSION... KEY MESSAGE 1...1-4 inches of snow is expected late tonight into Saturday across interior northern and western MA and NW CT, with localized amounts up to 6 inches in the Berkshires. Interesting set up late tonight into Sat as a series of shortwaves move into the region. We have one shortwave moving in late tonight with a second stronger shortwave approaching from the west Sat afternoon. A modest low level jet will bring increasing moisture into the region with a pronounced mid level boundary developing across western New Eng. Deep moisture plume accompanying this boundary and the resulting mid level frontogenesis will bring a period of snow to mainly interior northern and western MA into portions of western CT late tonight into Sat. We also briefly have the left exit region of the upper jet on Saturday to enhance lift across the region. The snow develops after midnight through daybreak and will initially be focused mainly NW of HFD-ORH-FIT. The axis of steadiest snow may shift even further NW after 12z to western MA, then as the mid level boundary and strongest lift moves east the axis of snow will gradually move east into central MA and portions of CT into the afternoon. However, there will be boundary layer issues in the lower elevations and especially across eastern MA, RI and eastern CT where temps will rise into the 40s. So looking at mostly rain here as the axis of precip moves east. 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. There is a period of decent lift in the snow growth region during Sat afternoon across western MA where snowfall rates may briefly approach 1"/hr before the snow moves to the east mid-late afternoon. Snow accumulations will be mainly confined to NW of BDL-ORH-FIT where 1-4 inches is expected, the lesser amounts in the low elevations. The heaviest accums will likely be found in the Berkshires where locally up to 6 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. The snow will impact travel conditions especially from the Berkshires to 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 Sat evening with dry weather Sat night ahead of next system approaching from the south. KEY MESSAGE 2...Offshore low pressure system may bring plowable snow to portions of the region Sunday and Sunday night. The track and westward extent remains uncertain leading to a larger range in potential snow totals at this time. We continue to monitor the potential for a coastal system to bring snow to portions of the southern New England Sunday afternoon through early Monday morning. However, there still remains considerable uncertainty regarding the track of the system and the westward extent of the shield of plowable snowfall. There is a general consensus in the synoptic set-up with a northern stream piece of shortwave energy moving east and a southern stream system/low pressure tracking tracking north through the vicinity of the benchmark. This will provide the needed lift and moisture for precipitation. Although only a few days away, there is still considerable variance in the surface low track among deterministic and ensemble guidance with solutions shifting from run to run still. The newer 12Z guidance brought subtle shifts in the surface low track from previous runs and continued model to model spread. However, it can be said that most guidance now has had more consistency with at least a signal for any QPF in a good portion of southern New England, even at the 25th percentiles of ensemble guidance. The NAM is one of the notable outliers with a well offshore track and a complete miss. For example, the AI GFS/ECMWF have stay consistent with further west tracks resulting in higher probabilities for plowable snow extending further into the interior and north in southern New England as opposed to other guidance that keeps higher probabilities confined to the southeast. The continued track shifts are making it difficult to determine the the west/north extent of the 2"+ snowfall. All a sign that all guidance remains to be considered and each run to be taken with a grain of salt. Best way forward is to not lock into any run or model despite it being a few days out. We have a little more confidence in accumulating snowfall overall. The greatest probabilities for seeing 2"+ of snow are generally southeast of the Boston to Providence corridor, followed lower probabilities for rest of RI, northeast CT, pushing back toward Worcester and lower as you go further west. It is still worth considering the potential for a further west extent of plowable totals at this time. Across all guidance, the probabilities for 6"+ are low to none which at least leans totals more likely toward the Advisory level in the favored areas. Exact timing is still uncertain; however, there is a general consensus for snow to begin sometime in the afternoon Sunday before pushing out very early Monday morning. Details should continue to become more clear as we get even closer which will help nudge amounts and potential Winter Advisories/headlines. KEY MESSAGE 3...Arctic cold front pushes through Monday night bringing well below normal temperatures and bitterly cold wind chills with the coldest temperatures felt Tuesday. Gale force winds and freezing spray for the waters into Wednesday. There is continued strong agreement between deterministic and ensemble guidance for a deep trough over the eastern CONUS early next week bringing well below normal temperatures. An arctic front will sweep across the region Monday night with strong cold air advection behind it. 850mb temperatures fall to -20 to -23C by Tuesday which is well below normal, even for January. This will translate to the surface with high temperatures Tuesday ranging between 15 to 25 degrees. To put it into perspective, that`s about 10 to 15 degrees below normal temperatures for that time of year. To add on, winds will be favored to be breezy to gusty Monday night and Tuesday. Winds 30-40 kts aloft, tightened pressure gradient, and strong cold advection will support efficient mixing of gusty winds to the surface. No signal for strong gusts at this time, but could see gusts 20-35 mph Monday night through Tuesday. This will bring wind chill values into the negative single digits to single digits Tuesday morning and single digits in most spots during the day Tuesday. Gale force winds remain possible over the waters Monday night- Tuesday which also rises the risk for freezing spray, potentially moderate in spots. KEY MESSAGE 4...Slightly warmer temperatures arrive by later Wednesday with a period of snow possible late Wednesday into Thursday. The deep upper level trough responsible for the bitter cold temperatures lifts north into Wednesday followed by height rises. This will help moderate temperatures Wednesday into Thursday. Highs Wednesday still remain below normal, although not as cold as Tuesday with temperatures in the 20s. A mid-level shortwave moves across the Great Lakes potentially bringing a period of snow Wednesday night into Thursday. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Tonight and Saturday...Moderate confidence. MVFR conditions will develop across parts of interior southern New England between 6z and 12z in snow with perhaps some brief IFR conditions too. These conditions will continue at times on Sat. Generally looking at 1-3" of snow across parts of western/central MA and perhaps portions of far northern CT with perhaps some 3-6" amounts in the highest terrain. Temps rising above freezing should result in wet runways by Sat afternoon outside the highest terrain of the Berks and northern Worcester Hills. Meanwhile...across eastern MA and RI just a few brief rain/wet snow showers with mainly VFR conditions persisting. Saturday Night...High confidence. VFR, lingering MVFR across higher terrain of central and western Massachusetts. Light W wind 5-10 knots. 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 IFR possible. Breezy. Chance SN. Sunday Night: VFR. Breezy. Chance SN. Martin Luther King Jr Day through Tuesday: VFR. Windy with gusts up to 35 kt. Tuesday Night: VFR. Windy with local gusts up to 30 kt. Wednesday: Breezy. && .MARINE... Through Saturday night...High Confidence. Gusty winds will continue to diminish with speeds dropping below 20 kt after midnight. A period of gusty S-SW winds will develop Sat as a low level jet moves into the region with gusts to 25+ kt, then diminishing Sat night. Seas will gradually subside tonight to 4-6 ft over outer waters, then increase over southern waters during Sat. Outlook /Sunday through Wednesday/... Sunday: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of snow, chance of rain. Areas of visibility 1 nm or less. Sunday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Snow. Local visibility 1 nm or less. Martin Luther King Jr Day: Low risk for gale force winds with gusts up to 40 kt. Areas of rough seas. Monday Night: gale force winds with gusts up to 45 kt. Areas of rough seas. Freezing spray, slight chance of snow showers. Tuesday: Moderate risk for gale force winds with gusts up to 40 kt. Areas of rough seas. Freezing spray, slight chance of snow showers. Tuesday Night: Low risk for gale force winds with gusts up to 35 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, slight chance of snow showers. && .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- 254>256. && $$