AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 352 AM EST Fri Jan 30 2026 .WHAT HAS CHANGED... Cold Weather Advisories continue into this morning for hazardous wind chills. While still frigid, the potential for hazardous wind chills tonight into Saturday morning is more marginal. Growing confidence in a more offshore pass to the coastal storm Sunday. The bulk of the storm`s impacts now look more confined to southeast New England. && .KEY MESSAGES... - Frigid temperatures today into Saturday morning. - A coastal storm looks more likely to pass offshore of Southern New England Sunday into Sunday night. Greatest overall impacts from accumulating snow and gusty winds are across South Shore, Cape Cod and the Islands Sunday and Sunday night. Lighter- accumulating snow with lesser overall impact further north and west into the Boston-Providence corridor Sunday. - Minor to moderate coastal flooding possible Sunday into Monday. && .DISCUSSION... Key Message 1...Frigid temperatures today into Saturday morning. Cold Weather Advisories continue into this morning. Still a few more hours to go, and while there are still some locations in the hills of Worcester County and the Berkshires where wind chills have been as low as 15 to 25 below, wind chill values across the reaminder of Southern New England have been in the zero to -10F range. Continue to dress in layers if venturing outside with the lowest wind chills expected by daybreak. It will still be a rather frigid day even when the sun comes up, with highs in the single digits to the mid teens. Even though we`ll be starting tonight colder than we did last night, expected lighter northwesterly wind speeds tonight could limit how low wind chills get tonight/early Saturday morning. Lowest wind chills in most areas are around the -5 to around the -15F range, thus a bit more marginal, but could be low enough in the higher terrain to possibly warrant cold weather advisories. We opted to refrain from extending the Advisories until we get a better sense as to how low wind chills got this morning. Even if the winds turn out lighter, lows range between 5 to 10 below in most areas, and around 0 to 5 below near the coastlines. Key Message 2...A coastal storm looks more likely to pass offshore of Southern New England Sunday into Sunday night. Greatest overall impacts from accumulating snow and gusty winds are across South Shore, Cape Cod and the Islands Sunday and Sunday night. Lighter-accumulating snow with lesser overall impact into the Boston-Providence corridor Sunday. Continuing the trend yesterday, the 00z/30th ensembles and deterministic guidance continued to show a powerful sub-980 mb coastal storm offshore the NC/SC coast Saturday and Saturday night, moving ENE south of the 40N/70W benchmark Sunday and into Atlantic Canada Sunday night. The 00z ECMWF/GFS/Canadian ensembles now show rather tight clustering of member low pressure centers clustered south of 40N latitude until it is well south of Nova Scotia. The odds of a substantial northwestward track adjustment and greater snowfall potential for a larger portion of Southern New England real estate is dwindling now, with an offshore pass being favored. Even with the offshore pass more favored, the system`s anticipated large size as it moves through the northwestern Atlantic waters will lead to at least some impact from accumulating snowfall, gusty winds, large waves and coastal flooding/beach and dune erosion. It still looks as though the steadiest accumulating snowfall is primarily confined to South Shore, Cape Cod and the Islands. But even there, snow amounts were decreased following the continued downward trend in the 03z NBM 5.0 snowfall exceedance probabilities of 6-inches (down to 25-50%) and 12-inches (down to 10-15%). The ECMWF continues to be the wettest in terms of liquid-equivalent precipitation across the guidance, but in the face of a dry high pressure into interior western/northern New England, the western extent of its modeled QPF shield has decreased. The best chance for moderate to at times heavy snow and more significant snow totals seems more limited to Nantucket, where official snow amounts are in the 6 to 8 inch range. Across the remainder of Cape Cod, Martha`s Vineyard, and southern Plymouth County, snow amounts are in the 4 to 6 inch range. We held the Winter Storm Watch for this package. Given the storm`s large northeasterly fetch, light-accumulating snow from ocean effect bands could still develop further north and west into the Boston-Providence I-95 corridor into southeast MA Sunday morning to early afternoon, at least until the storm pulls away and the winds turn more N to NW Sunday afternoon. Even still, with poor snowgrowth, that`s not expected to amount to not much more than a couple inches, with lesser overall impact (probabilities of exceeding 4 or more inches being less than 20% for this area). Dry weather is anticipated further westward into western RI, central/western MA and northern CT. Gusty to strong northeast to north winds are still expected given the strong pressure gradient, strongest across the Cape and Islands where a 950 mb northerly jetstreak of 55-60 kt is located. Gusts in the 35-45 mph range seem likely for the Cape and Islands, with gusts as high as 55 mph over the eastern/southeast outer waters. Storm and Gale Watches were maintained for the waters. Northeast to northerly winds gusting to 25-35 mph should be more common across the remainder of Southern New England. Key Message 3...Minor to moderate coastal flooding possible Sunday into Monday. A Coastal Flood Watch continues for the eastern Massachusetts coastline Sunday into Monday. High astronomical tides combined with at least a 1 to 3 foot storm surge and strong N/NE winds will bring the potential for minor to perhaps moderate coastal flooding along the eastern Massachusetts coast during high tides Sunday morning, Sunday evening, and Monday around midday. Based upon the projected offshore track of the coastal storm, the highest winds and storm surge should be focused closer to Cape Cod, Nantucket, and Marthas Vineyard where the higher chances of seeing moderate flooding exists. However, building seas of 20-25 feet offshore will add additional impacts to the ocean exposed coastline from Plymouth County north to the Merrimack River, so despite lower water levels, those areas could still see moderate impacts. Additionally, the long overwater fetch should result in significant beach and dune erosion, especially in areas that have been hard hit in recent years including Newburyport/Plum Island, Sandwich, Chatham, and Edgartown. Should the storm trend farther offshore, the threat of coastal flooding would decrease, but given the high astronomical tides it is reasonable to expect at least minor coastal flooding spanning three tide cycles. A trend closer to New England would raise the odds of moderate flooding over much of the coastline, but the chances of reaching major flood impacts would still remain very low. As a reminder, minor flooding refers to shallow flooding up to 1 foot deep and can result in temporary road closures on more vulnerable coastal roads. Moderate flooding refers to flooding 1 to 3 feet deep and can cause more widespread road closures, damage to shorefront property, and debris on coastal roads from large waves. Vehicles left in flood prone areas can also be flooded. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Through Saturday...High confidence. VFR. Increasing west winds tonight, however, terminals that are able to decouple from the boundary layer will experience LLWS with winds aloft between 30-35 knots. Winds remain westerly and gust 20-25 knots on Friday. Decreasing winds friday night through saturday from the NW at 5-10 knots. KBOS Terminal...High Confidence in TAF. VFR. Gusty west at 20-25 knots KBDL Terminal...High Confidence in TAF. VFR. West winds around 10 knots tonight. LLWS possible with winds aloft around 30-35 knots. Gusty west winds Friday. Outlook /Saturday Night through Tuesday/... Saturday Night: VFR. Windy with areas of gusts up to 35 kt. Chance SN. Sunday: Mainly VFR, with local MVFR possible. Strong winds with gusts up to 50 kt. Chance SN. Sunday Night: VFR. Strong winds with gusts up to 50 kt. Slight chance SN. Monday through Monday Night: VFR. Breezy. Tuesday: VFR. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. * Moderate to heavy freezing spray developing on the waters tonight into Friday * Dangerous marine conditions developing Sunday A period of WNW gusts to 25-30 kt will continue today, then diminishing wind tonight. The gusty winds will be accompanied by a reinforcing shot of arctic air which will result in widespread moderate freezing spray with areas of heavy freezing spray over some of the nearshore waters. Significant accretion of ice is expected on vessels over the waters. Freezing spray advisories and heavy freezing spray warnings remain in effect. Our attention turns to a powerful ocean storm which tracks well south and east of the waters on Sunday. Potential for storm force NE gusts to 50-55 kt over the outer waters peaking during Sunday, with 40-50 kt gusts over nearshore waters. Seas expected to build to 20+ ft on the waters east of Cape Cod resulting in dangerous conditions for mariners. In additions, areas of light to moderate freezing spray will develop Sat night though Sun night. Outlook /Saturday Night through Tuesday/... Saturday Night: Low risk for gale force winds with gusts up to 40 kt. Local rough seas. Freezing spray, chance of snow. Sunday: gale force winds with gusts up to 45 kt. Rough seas up to 17 ft. Snow likely, freezing spray. Areas of visibility 1 nm or less. Sunday Night: gale force winds with gusts up to 45 kt. Rough seas up to 19 ft. Freezing spray, chance of snow. Monday: Low risk for Small Craft Advisory winds with local gusts up to 30 kt. Rough seas up to 17 ft. Freezing spray. Monday Night: Winds less than 25 kt. Areas of rough seas. Tuesday: Winds less than 25 kt. Areas of seas approaching 5 ft. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...Cold Weather Advisory until 11 AM EST this morning for CTZ002>004. MA...Cold Weather Advisory until 11 AM EST this morning for MAZ002>022-026. Coastal Flood Watch from Sunday morning through Monday afternoon for MAZ007-015-016-019-022>024. Winter Storm Watch from late Saturday night through late Sunday night for MAZ022>024. RI...Cold Weather Advisory until 11 AM EST this morning for RIZ001>007. MARINE...Small Craft Advisory until 7 PM EST this evening for ANZ230- 236. Gale Watch from Sunday morning through Sunday evening for ANZ230. Small Craft Advisory until 10 PM EST this evening for ANZ231>235-237-251. Freezing Spray Advisory until 1 AM EST Saturday for ANZ231-235- 237-250-251-254-256. Storm Watch from Sunday morning through late Sunday night for ANZ231-232-250-254>256. Heavy Freezing Spray Warning until 1 AM EST Saturday for ANZ232>234-255. Gale Watch from late Saturday night through late Sunday night for ANZ233>235-237. Freezing Spray Advisory until 7 PM EST this evening for ANZ236. Gale Watch from late Saturday night through Sunday evening for ANZ236. Small Craft Advisory until 1 AM EST Saturday for ANZ250- 254>256. Gale Watch from late Saturday night through Monday morning for ANZ251. && $$