AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 205 PM EST Sun Jan 18 2026 .WHAT HAS CHANGED... No significant changes to the forecast. Winter Weather Advisories remain in effect tonight. && .KEY MESSAGES... - Plowable snow tonight with total accumulations of 3-5" with localized 6" amounts possible across eastern MA/RI. Heaviest snow/worst of the travel conditions between 6 pm and 2 am. Snow ends from west to east between 3am and 9am Monday. - Arctic cold front sweeps across the region Mon night bringing well below normal temperatures and bitterly cold wind chills & temps. The peak of the cold weather will be Tue into Wed am. - Milder temps arrive Wed night-Thu with perhaps a brief period of light snow showers or even light rain showers near the coast. - Another shot of very cold air works into the region behind a cold front Thu night into Fri. && .DISCUSSION... KEY MESSAGE 1...Plowable snow today-tonight with total accumulations of 2-6" with localized 7" amounts possible across eastern MA/RI. Heaviest snow/worst of the travel conditions between 5 pm and 1 am...but snow showers may linger for the Mon am commute. An elongated shortwave trough stretching from the northern Great Lakes down into the Gulf Coast will spin up a coastal low offshore, passing just southeast of the benchmark this evening. Guidance held steady, with total QPF across the region ranging from 1/2 to 3/4 inches, south and east of the I-95 corridor, including the Cape and Islands. QPF ticked up a bit north and west of the I-95 corridor all the way to the northern Berkshires with 1/4 to 1/2 inch of QPF. How this translates into snowfall accumulation will depend heavily on temperatures and where mid-level forcing sets up. Temperatures during this event will be marginal, with inland areas staying near freezing and the Cape and Islands staying at or above freezing. With the best mid-level forcing near the Cape and Islands, we will likely see snow at temperatures up to 36F as snow rates will be able to overcome the warm temps. The primary source of uncertainty is the temperature at which snow will accumulate on paved surfaces. Because of the warm temps, we continued to trend total accumulations down to 0.5-1.5 inches for the outer Cape and the Islands; however, if temps cool below freezing, snow accumulations could exceed 2-4. The highest confidence in snow accumulations remains along the I-95 corridor in eastern MA and into RI, where good mid-level forcing and temperatures near or below freezing will overlap. Snow accumulations in this area will range from 3-5 inches, with localized spots up to 6 inches possible. To the north and west of the I-95 corridor, mid-level forcing begins to drop off; however, cooler temperatures will allow snow ratios to be higher, ranging between 12-1 to 16-1. Snow totals north and west of the I-95 corridor, including all of CT, will range from 2-4 inches, with localized areas of 5 inches. After the lull in snowfall this afternoon, steady light snow will begin to overspread the region once again through 6 pm. Snow rates will start to tick up after 6 pm, increasing to 0.5 to 1.5 inches per hour. Snow becomes light again after 2-4 am and tapers off from west to east through 6-9 am this morning. Snow showers may linger over eastern MA until noon, but additional accumulations will be light. The most difficult travel period will be between 6 pm and 2 am tonight. However, with lingering snow showers into Monday morning, the AM commute will likely be impacted. Low temperatures on Monday morning are expected to drop into the low to mid-20s across the region, which could cause any standing water from melting snow to refreeze, especially on untreated surfaces. High temperatures Monday afternoon rebound into the low to mid 30s, allowing some melting. Winds become gusty out of the WSW Monday afternoon at 15-20mph, making it feel like the low to mid 20s. KEY MESSAGE 2...Arctic cold front sweeps across the region 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 to the middle 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 by Wed. We should see high temps recover into the middle 20s and lower 30s by Wed afternoon...which is still below normal. KEY MESSAGE 3...Milder temps arrive Wed night-Thu with perhaps a brief period of light snow showers or even light rain showers near the coast. Low pressure tracking across Quebec will result in much milder air working back into the region on southwest flow. 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. KEY MESSAGE 4...Another shot of very cold air works into the region behind a cold front Thu night into Fri. Another shot of very cold air works into southern New England behind a strong cold front Thu night into Fri. Highs may be held in the upper 20s and lower 30s on Fri but with mainly dry weather. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 18z TAF Update... Moderate confidence. Overall forecast trends have not changed substantially. Currently much of the area is in a bit of a lull between the initial round of precipitation, and the next, more substantial batch. Predominantly IFR conditions in most areas, with areas of 2-4sm in BR and then -SN, especially across southeast areas. Temperatures are marginal for some -RA across parts of the Cape and the Islands. Precipitation, primarily in the form of snow (except with some rain mixed in across the Cape and Islands) will overspread the region between 20-23z. Best estimate is that the core of the heaviest precipitation will be generally from 00-07z (earliest in the west). Most locations should see a few hours of 1/2SM in moderate to briefly heavy snowfall during this period. Still quite a bit of inconsistency amongst models, so exact timing has an error bar of roughly 2 to 3 hours. Snow will taper off from west to east in the 10-14z period. Expect IFR/MVFR ceilings and visibilities to continue a few hours after that, until drier air starts moving in. Conditions will trend toward VFR Monday afternoon, with west winds gusting 20kt or higher in many areas, especially after 18z. Monday Night is expected to feature VFR conditions, though with still some west winds gusting 15-20kt or so. KBOS Terminal...Moderate confidence in TAF. Though the TAF starts with no mention of snow through 21z, can`t rule out the occasional flurry. Winds should transition from SW to N to NE from 19 to 21z. Specific timing of the heaviest of the snow could be off by up to 2 hours. KBDL Terminal...Moderate confidence in TAF. Specific timing of the heaviest of the snow could be off by up to 2 hours. Outlook /Monday Night through Friday/... Tuesday through Wednesday: VFR. Breezy. Wednesday Night: VFR. Breezy. Slight chance SN. Thursday: VFR. Breezy. Chance RA, chance SN. Thursday Night: VFR. Breezy. Slight chance SN. Friday: VFR. Breezy. && .MARINE... Today and tonight...High Confidence. Residual seas of 5-8 feet on the southern waters and 3-6 feet on the eastern waters is the basis for a continued Small Craft Advisory on the outer waters, which is in effect through Sunday morning. Coastal storm passes off shore today, bringing a rain/snow mixture and poor visby conditions. Brief lull in advisory level conditions, seas fall below 5 feet with light winds. Increasing wind speed/gusts with seas coming up late tonight into early Monday, likely will need to be handled with a renewed Small Craft Advisory. Outlook /Monday Night through Friday/... Tuesday: Strong winds with gusts up to 35 kt. Areas of rough seas. Freezing spray. Tuesday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Local rough seas. Freezing spray. Wednesday: Winds less than 25 kt. Seas locally approaching 5 ft. Wednesday Night through Thursday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas. Chance of rain. Thursday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Chance of freezing spray, slight chance of rain, slight chance of snow. Friday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of seas approaching 5 ft. Chance of freezing spray. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...Winter Weather Advisory until 7 AM EST Monday for CTZ002>004. MA...Winter Weather Advisory until 7 AM EST Monday for MAZ002>023- 026. RI...Winter Weather Advisory until 7 AM EST Monday for RIZ001>007. MARINE...Gale Watch from Monday afternoon through Tuesday morning for ANZ230>234-236-251. Gale Watch from Monday afternoon through Tuesday morning for ANZ235-237. Gale Watch from Monday morning through Tuesday morning for ANZ250-254>256. && $$