AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 221 PM EST Mon Mar 2 2026 .WHAT HAS CHANGED... Winter Weather Advisories posted for Tuesday afternoon to Wednesday morning for interior Southern New England for light accretion of icing and minor snow and sleet accumulation. There is also increasing confidence on a period of a wintry mix Thursday night into Friday across northern MA. && .KEY MESSAGES... - Wintry mix of snow, sleet and freezing rain brings slippery roads to interior Southern New England Tue afternoon and evening; brief wet snow changes to plain rain and minimal to nil impact for the MA/RI coastal plain. - Dry and very pleasant weather arrives Wednesday, feeling mild with March sunshine, light winds and highs in the upper 40s to lower 50s. - A period of wintry precip remains possible Thu night into early Fri. - Pattern change towards milder weather this weekend and potentially warmer next week. && .DISCUSSION... 215 PM Update: Key Message 1...Wintry mix of snow, sleet and freezing rain brings slippery roads to interior Southern New England Tue afternoon and evening; brief wet snow changes to plain rain and minimal to nil impact for the MA/RI coastal plain. Quasi-stationary frontal boundary lying across the OH Valley and mid- Atlantic Piedmont region will lift northward on Tue, spreading clouds and warm-frontal precipitation northward into Southern New England Tue starting mainly during the early to mid-afternoon hours. This precip will be falling into a retreating modified-Arctic airmass coming out of another chilly night tonight. However the combination of onshore/east flow and associated warming surface temps along the coastal plain to go along with limited surface heating before turning overcast during the morning hours could offset evaporative/wet-bulb cooling until precip arrives. Given the now-delayed arrival of precip and questions on how soon arrival of clouds come in, how cold surface temps could still prove to be a challenge; utilized some of the colder 2-m temps given the potential for wet-bulbing which model-blended solutions tend to wash out or not resolve as well. We still expect a wintry mix of snow/sleet/freezing rain in interior Southern New England during the afternoon and evening hours where winter weather advisories have been posted from Tue noontime til early Wed morning. The main impact in those areas is from icing, with up to a tenth of an inch of ice accretion, and up to an inch of combined snow/sleet accumulation at outset. It is somewhat debatable/uncertain how much road impact there may be during the Tue afternoon drive, and that`s especially the case if cloud cover is slow to arrive and ends up permitting several hours of strong early-March sun to warm up pavement; feel more confident in at least slippery road conditions developing by the early evening hours, as temps hover or slightly cool on light NE drainage winds which will help sustain frozen p-types in interior Southern New England until precip comes to an end Wed morning. In the coastal plain, a brief period of wet snow during the early to midafternoon Tuesday should mixover with rain with temps in the mid 30s, then change to a plain rain for the remainder of the evening where adverse road impacts should prove minimal. Key Message 2...Dry and very pleasant weather arrives Wednesday, feeling mild with March sunsine, light winds and highs in the upper 40s to lower 50s. Short wave ridging in fast flow aloft advects across SNE, providing a very pleasant, dry Wed across SNE. Mild with highs in the upper 40s and low 50s. It feel even milder given light winds and full March sunshine. Key Message 3...A period of wintry precip remains possible Thu night into early Fri. Fast, wavy zonal upper air pattern yields the next precip event for SNE Thu night into Fri. 1040 mb anticyclone over southeast Quebec into the Maritimes will yield a wedge of shallow cold air into SNE. This will support the risk of a wintry mix this period, with highest probs of an icy mix across northern MA. It`s possible this shallow cold air could bleed farther south, with a low risk of a wintry mix near or into the I-95 corridor. Just too early to tell, this needs to be watched. Not a major winter event, but it only takes a small amount of ice to impact travel. Stay tuned. Key Message 4...Pattern change toward milder weather this weekend and potentially warmer next week. Good multi-model agreement on a pattern change beginning this weekend and continuing into next week, with a southeast/western Atlantic ridge. This will promote SW up the eastern seaboard into SNE, with temps rising into the low 50s Saturday, and possibly low 60s away from the south coast Sunday and Monday. Dew pts will be rising into the low 50s then, so definitely a mild feel to the airmass, along with accelerating the erosion of the the snow pack with dew pts rising into the 50s and SW winds 10-15 mph providing some mixing around the snowcover. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 18z TAF Update: Through 12z Tuesday: High confidence. VFR. Light northerly winds become SW late in the afternoon, and become S/SW 5 kt or less thru tonight. Tuesday: Moderate confidence. VFR should generally prevail thru at least 17z Tue, although with lowering ceilings. Conditions deteriorate to MVFR after 18z with wintry mix of precip types, then to IFR late-day. Predominant SN/FZRA interior SNE with minor snow/ice accums and icy runways more likely for those airports; coastal SNE airports (PVD, BOS, Cape) initial light snow mixed with rain with nil accum and mainly wet runways, changing to plain rain after 22z. Winds become SE/ESE around 5-10 kt. Tuesday Night: Moderate confidence. IFR/LIFR ceilings, with FZRA mainly higher terrain of southern New England and plain rain for the majority of southern New England. Precip ends from west to east after 10z, but rain may linger along the south coast into early Wed AM. ESE winds 5-10 kt lighten and shift to W/WNW as precip ends west to east. KBOS Terminal...High confidence in TAF. VFR, ESE winds 5 kt or less continue thru 22z before flipping to S. These conditions continue thru Tue AM, MVFR develops after 19z Tue, with brief period of 4SM -SNRA 21-23z before becoming RA by 23z. Nil accum and wet runways expected given air temps 32-35F. KBDL Terminal...High confidence in TAF. VFR thru at least 16z Tue. Ceilings deteriorate to MVFR/IFR with light snow, transitioning to freezing rain between ~21-02z. It is more uncertain how long freezing rain may last as temps may hover around 31-33F overnight. Outlook /Tuesday Night through Saturday/... Wednesday: VFR. Slight chance RA, slight chance FZRA. Wednesday Night: VFR. Slight chance SN. Thursday: Mainly VFR, with local IFR possible. Chance RA. Thursday Night: MVFR/IFR conditions possible. Breezy. Chance RA, FZRA likely. Friday: MVFR/IFR conditions possible. Breezy. RA likely, FZRA likely. Friday Night: MVFR/IFR conditions possible. Slight chance RA. Saturday: Mainly VFR, with areas IFR possible. Breezy. Slight chance RA. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Through Tuesday Night...High confidence. Winds and seas remain below small craft advisory thresholds through at least Tuesday afternoon, with south to southeast winds around 10-15 kt. Seas may begin to build late Tuesday night into Wednesday to around 4-6 ft on the southeast outer waters, which could prompt small craft advisories. Reduced visibilities possible in snow to rain Tuesday afternoon. Outlook /Tuesday Night through Saturday/... Wednesday: Winds less than 25 kt. Seas up to 5 ft. Slight chance of rain, slight chance of freezing rain. Wednesday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain. Thursday: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain. Thursday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Rain likely. Friday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas. Rain likely. Friday Night through Saturday: Winds less than 25 kt. Areas of rough seas. Slight chance of rain. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...Winter Weather Advisory from noon Tuesday to 7 AM EST Wednesday for CTZ002>004. MA...Winter Weather Advisory from noon Tuesday to 7 AM EST Wednesday for MAZ002>012-014-026. RI...Winter Weather Advisory from noon Tuesday to 7 AM EST Wednesday for RIZ001. MARINE...None. && $$