Area Forecast Discussion
Issued by NWS Boston, MA
Issued by NWS Boston, MA
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388 FXUS61 KBOX 041139 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 639 AM EST Sun Jan 4 2026 .WHAT HAS CHANGED... Light snowfall looks even less widespread than what was previously forecast. Sharply colder tonight, with a modest recovery Monday. Uncertainty remains regarding mixed precipitation for southern New England Tuesday night into Wednesday. Another round of rain is possible towards the end of next week, but timing is uncertain. && .KEY MESSAGES... - Light snow this morning with little to no accumulation. - Very cold conditions develop tonight into Monday morning. - Light snow Monday evening into Tuesday morning. - Chance for snow and mixed precipitation Tuesday night into Wednesday. - Unsettled again around Friday. && .DISCUSSION... KEY MESSAGE 1...Light snow this morning with little to no accumulation. Still monitoring a broad area of light reflectivity over PA/NY state. Thus far, not seeing much drop in visibility and most cloud bases were rather high up. Still thinking while most will actually see some snow later this morning, it will not amount to much, generally less than 0.5". Latest high resolution models slowed the timing by a couple of hours, with the snowfall now moving offshore by mid morning. Snow may linger a bit longer across the Cape and Nantucket into early afternoon due to some ocean enhancement as winds shift northwest this morning. KEY MESSAGE 2...Very cold conditions develop tonight into Monday morning. Still looking sharply colder tonight into Monday. A high pressure moves into the central Appalachians, clearing skies and turning winds light NW. The combination of cold advection and radiational cooling is expected to push temperatures into the single digits away from the urban centers and immediate coast, which should be in the teens. KEY MESSAGE 3...Light snow Monday evening into Tuesday morning. A warm front is still expected to shift north late Monday into Tuesday morning along with weak low pressure that may lead to some scattered snow showers. Guidance still indicates that this will not be very impactful snowfall, with totals most likely remaining less than an inch. Higher probabilities for an inch remain across the Berkshires and the Worcester Hills. KEY MESSAGE 4...Chance for snow and mixed precipitation Tuesday night into Wednesday. Much of Tuesday should be dry following the snow showers from Monday night as high pressure moves in briefly ahead of a stronger shortwave from the Great Lakes. As this shortwave and associated surface low pressure move in, warmer, more moist air is advected in over southern New England. 925 mb temperatures begin to increase to just around 0C heading into Tuesday night on its approach, and 850 mb temperatures get to just above 0C. With this warmer air aloft and colder air still at the surface, mixed precipitation across much of southern New England is a solid possibility. Latest ensemble guidance still has low probs for any significant ice accumulation, but it is not completely negligible. Soundings continue to favor this period of freezing rain before switching to all rain as surface temperatures increase heading into Wednesday morning. As this event still remains a few days out, a number of details still need to be ironed out and should become clearer as we get closer to it. KEY MESSAGE 5...Unsettled again towards the end of the week. As the midweek system makes its exit, mid-level ridging and surface high pressure with it make a return ahead of another disturbance approaching towards the end of the week. This will not last long, however. Significant discrepancies remain across the guidance at this time, but the general pattern has a stronger shortwave beginning to make its way east from the central US. NAEFS guidance indicates enhanced moisture with this system; PWATs are 1-2 standard deviations above average heading into the weekend. Temperatures aloft are also notably warmer across ensemble guidance. A rain event for southern New England towards the end of the week is what`s favored at this time, but current confidence is low since this event is still multiple days out. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High -greater than 60 percent. Today...High confidence. VFR with pockets of brief MVFR within any snowfall this morning. Light snow ends from W to E between 12-15Z. Light SN may linger through about 17Z across the Cape and Nantucket as winds shift NW this morning. Tonight... High confidence. VFR. W to NW winds between 5-10 kt early on, diminishing towards the morning hours Monday. Monday...High confidence. VFR for most. Areas MVFR developing during the afternoon from W to E during the afternoon in light snowfall, mainly across the higher terrain. KBOS Terminal...High confidence in TAF. KBDL Terminal...High confidence in TAF. Outlook /Monday Night through Thursday/... Monday Night: Mainly VFR, with local IFR possible. Chance SN, chance FZRA. Tuesday: Mainly VFR, with areas MVFR possible. Chance FZRA, slight chance RA. Tuesday Night: MVFR/IFR conditions possible. FZRA likely, chance RA. Wednesday: Mainly VFR, with areas IFR possible. Chance RA, chance FZRA. Wednesday Night: Mainly VFR, with local MVFR possible. Slight chance FZRA. Thursday: VFR. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. High Confidence. Relatively light winds and seas for today. Reduced visibility in light snow possible, especially across the eastern coastal waters between 6 AM and noon. Area of Small Craft Advisory conditions possible across the outermost waters later tonight into Monday. At this time, not thinking the majority of the waters will need an advisory, so no headlines for now. Outlook /Monday Night through Thursday/... Monday Night: Winds less than 25 kt. Chance of rain, chance of snow, freezing rain likely, patchy fog. Local visibility 1 to 3 nm. Tuesday: Winds less than 25 kt. Slight chance of rain, slight chance of freezing rain. Tuesday Night through Wednesday: Winds less than 25 kt. Chance of rain. Wednesday Night: Winds less than 25 kt. Thursday: Winds less than 25 kt. Seas locally approaching 5 ft. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...None. && $$ DISCUSSION...Belk/Hrencecin AVIATION...Belk/Hrencecin MARINE...Belk/Hrencecin