AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 256 PM EDT Sat Mar 21 2026 .WHAT HAS CHANGED... The risk for a band of accumulating snow has diminished Monday morning. However...we are watching for the potential for snow showers and perhaps a few snow squalls late Monday into Monday night across eastern New England and especially eastern Massachusetts. && .KEY MESSAGES... - Periods of mainly rain Sun-Sun night...but a brief period of snow at the onset very early Sun am mainly north of I-90. A coating to 1" of snow possible in the northwest Berks & northern ORH Hills. - A few lingering rain/snow showers possible Mon morning along the coastal plain...but thinking dry air likely wins out and the threat for accumulating snow has diminished Mon morning. However...we are watching for a round of snow showers/snow squall or two late Mon/Mon night central MA/RI and especially eastern MA. Minor snow accumulations are not out of the question. - Temperatures remain below average for the first half of the week then moderate by mid-week. Expecting an active upcoming period, with several rounds of quick hitting showers possible throughout the week. && .DISCUSSION... KEY MESSAGE 1...Periods of mainly rain Sun-Sun night...but a brief period of snow at the onset very early Sun am mainly north of I-90. A coating to 1" of snow possible in the northwest Berks & northern ORH Hills. A weak ridge of high pressure will result in dry weather this evening. A mid level shortwave/warm front will approach from the southwest after midnight into mid-morning Sunday. This should allow areas of precipitation to develop...mainly across western and northern MA initially. It is probably initially cold enough for a brief period of wet snow at the onset across the highest terrain of northern MA and possibly areas north of I-90. Any accumulations probably a coating to 1" of snow mainly in the highest terrain of the northwest Berks and northern Worcester Hills. Ptype should flip to all rain by mid to late Sun morning in all areas as warmer mid level air overspreads the region. Otherwise...a wave of low pressure across the mid-Atlantic will slowly move east. This will allow an area of steady rain to sink south from northern MA and eventually into CT/RI/SE MA Sun afternoon into Sun night. This is an ana-frontal setup...so we do expect a narrow band of rather strong mid level frontogenesis. These are often tough to locate because they tend to impact a narrow area. Currently this looks to be towards the south coast...where 0.75 to perhaps up to 1.50 inches of rain would be possible. KEY MESSAGE 2...A few lingering rain/snow showers possible Mon morning along the coastal plain...but thinking dry air likely wins out and the threat for accumulating snow has diminished Mon morning. However...we are watching for a round of snow showers/snow squall or two late Mon/Mon night central MA/RI and especially eastern MA. Minor snow accumulations are not out of the question. A few lingering rain/snow showers possible Mon morning on the coastal plain...but for the most part it looks like the dry air will have won out. So feel that the accumulating snow potential has diminished Mon morning. We may have a few snow flakes in the air...but right now thinking the threat of any impacts is rather low. However...we are watching a rather potent shortwave/cold pool aloft that will be dropping into our region later Mon into Mon night. This combined with plenty of left over low level moisture and instability...should allow an area of snow showers/snow squall or two to develop late Mon into Mon night across central MA/RI and particularly eastern MA. In fact...the guidance indicates an inverted trough feature may setup across eastern MA Mon night. Therefore...will need to watch for the potential of some minor snow accumulations Mon night in this region given temps falling below freezing. KEY MESSAGE 3...Temperatures remain below average for the first half of the week then moderate by mid-week. Expecting an active upcoming period, with several rounds of quick hitting showers possible throughout the week. High pressure builds in over southern New England Tuesday morning, allowing for a short period of clearing skies and drier conditions. High temperatures Tuesday will be just below normal for early spring. Ensembles continue to indicate a more active upper-air pattern with multiple shortwaves moving through as we head into the second half of next week. The AI ensembles are trending slightly more amplified than the regular ensembles which could lead to enhanced precipitation totals, but not expecting large amounts either way. Daytime temperatures are expected to reach into the low 50s with nighttime lows below freezing. If some of these showers pass through overnight, it`s possible some areas like the higher elevations could see a few snow flurries. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 18z TAF Update... This afternoon into Sunday night...Moderate confidence. VFR conditions persist through most of tonight. An approaching warm front should allow for some precipitation to overspread portions of mainly western and northern MA after midnight. Ptype will probably be initially in the form of some wet snow in the highest terrain of northern MA and possibly even north of I-90. Otherwise...Ptype should change to rain in all areas by mid- late Sun morning and gradually sink south and impact the rest of the region Sun afternoon and night. Conditions will lower to mainly MVFR levels but some localized IFR conditions possible too Sun into Sun night. NW wind gusts of 20-25 knots diminish by early evening and become light NE tonight. S-SW winds 5-10 knots Sun become N Sun night. Monday and Monday night...Moderate confidence. A few left over rain/snow showers possible Mon morning across the coastal plain. Otherwise...mainly MVFR ceilings should improve to VFR from west to east as the day wears along. However...a period of snow showers is possible late Mon into Mon night across central MA/RI and especially eastern MA. This may lower conditions back to MVFR levels with perhaps even localized brief IFR conditions. NNW 5-15 knots with some 20-25 knot gusts expected at times at least along the coastal plain. KBOS Terminal...Moderate confidence in TAF. KBDL Terminal...Moderate confidence in TAF. Outlook /Monday Night through Thursday/... Monday: Mainly VFR, with areas MVFR possible. Breezy. Chance SHRA, slight chance SHSN. Monday Night: VFR. Breezy. Chance SHSN. Tuesday: VFR. Tuesday Night through Wednesday: Breezy. Wednesday Night: Breezy. Slight chance RA, slight chance SN. Thursday: Breezy. Chance RA, chance SN. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. SCAs continue on most waters except Narragansett Bay and Boston Harbor. These will be gradually coming down through today, though will take longer out on the outer waters as seas begin to slowly decrease. West winds around 10-15 kt shift to NW by mid to late morning with gusts around 20 kt through sundown, then decreasing to around 10-15 kt early tonight, trending light and shifting to east/southeast toward Sunday morning. Winds Sunday then shift to S/SW and increase to around 10-15 kt with gusts nearing SCA criterion. Marine headlines could be needed for Sunday, but a better chance of SCA-level wind gusts and seas by Sunday night as winds turn to NE and increase to 25-30 kt. Outlook /Monday Night through Thursday/... Monday: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas. Chance of rain showers, slight chance of snow showers. Monday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas. Slight chance of snow showers. Tuesday: Winds less than 25 kt. Local rough seas. Tuesday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Wednesday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of seas approaching 5 ft. Wednesday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain. Thursday: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Seas up to 5 ft. Chance of rain. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ250- 254>256. && $$