Nantucket Sound Marine Forecast
| Today...Nw Winds 25 To 30 Kt, Becoming N This Afternoon. Gusts Up To 40 Kt. Seas 3 To 5 Ft. Wave Detail: N 5 Ft At 5 Seconds And E 2 Ft At 10 Seconds. A Chance Of Showers. |
| Tonight...N Winds 15 To 20 Kt With Gusts Up To 25 Kt, Becoming W 5 To 10 Kt After Midnight. Seas 3 To 5 Ft. Wave Detail: Ne 3 Ft At 4 Seconds And E 3 Ft At 10 Seconds. |
| Thu...W Winds 15 To 20 Kt With Gusts Up To 30 Kt. Seas 2 To 4 Ft. Wave Detail: W 4 Ft At 5 Seconds And E 3 Ft At 10 Seconds. |
| Thu Night...Nw Winds 25 To 30 Kt. Seas 3 To 5 Ft. Wave Detail: N 5 Ft At 5 Seconds And E 3 Ft At 10 Seconds. |
| Fri...N Winds 20 To 25 Kt, Diminishing To 15 To 20 Kt In The Afternoon. Seas 2 To 4 Ft. Wave Detail: N 4 Ft At 5 Seconds And E 2 Ft At 11 Seconds. |
| Fri Night...N Winds 10 To 15 Kt, Becoming Ne 5 To 10 Kt After Midnight. Seas 2 To 3 Ft. Wave Detail: N 2 Ft At 5 Seconds And E 2 Ft At 11 Seconds. A Chance Of Snow. Vsby 1 To 3 Nm After Midnight. |
| Sat...Ne Winds 10 To 15 Kt. Seas 2 To 3 Ft. A Chance Of Snow. |
| Sat Night...N Winds 10 To 15 Kt. Seas 2 To 3 Ft. |
| Sun...W Winds 10 To 15 Kt. Seas 2 To 3 Ft. A Chance Of Rain. |
| Sun Night...S Winds 20 To 25 Kt. Seas 2 To 4 Ft. Rain. Seas Are Reported As Significant Wave Height, Which Is The Average Of The Highest Third Of The Waves. Individual Wave Heights May Be More Than Twice The Significant Wave Height. |
| Area Forecast Discussion National Weather Service Boston/Norton MA 548am EST Wednesday Dec 24 2025 .WHAT HAS CHANGED... No significant changes to the forecast. .KEY MESSAGES... - Cold front brings gusty winds from the NNW at 35-45mph this morning - Ocean effect snow showers may bring light accumulating snow to portions of the eastern coast into Cape Cod today - Breezy with a few rain/snow showers Christmas Day. Temperatures fall quickly below freezing on Christmas Night with wind chill values in the single digits. - Lower-confidence forecast featuring snow, ice, and rain mix beginning late Friday through the weekend. KEY MESSAGE 1...Cold front brings gusty winds from the NNW at 35-45mph this morning A shortwave trough and weak cold front drop down from northern New England this morning. While this cold front is not bringing a large temperature swing with highs remaining in the mid-30s to low-40s, the main impact will be strong NNW winds this morning. Guidance still indicates a 45-50 knot LLJ moving through the region this morning. With the light cold air advection, it will take time for mixing to Be able to tap into the higher winds at 850mb. Bufkit sounds show the highest potential for gusts reaching above 35-45mph between 9 am and 1 pm before the LLJ begins to move offshore to the south, and the pressure gradient weakens. The best chance for 45- 50mph gusts remains in the high terrain and across the Cape and Islands, where wind advisories remain in effect. KEY MESSAGE 2...Ocean effect snow showers may bring light accumulating snow to portions of the eastern coast into Cape Cod today Surface low-pressure digs southeast from Ontario over The Gulf of Maine tomorrow morning into tomorrow afternoon. Hi-Res model guidance supports the development of an inverted trough that may provide sufficient forcing for some rain/snow showers along the east coast and The South Shore in particular. Temperatures will be marginal for snow-fall in the mid 30s, but some heavy wet flakes or rain will be a possibility between about 10am and 2pm tomorrow. If surface temperatures are cool enough for snow, we would expect minimal accumulations <1". Should temperatures trend cooler and meso-scale forcing trend stronger, we could see more substantial accumulations. The latest HREF model supports a 10-20 percent chance of accumulations greater than 1" along and east of the I-95 corridor in MA tomorrow. KEY MESSAGE 3...Breezy with a few rain/snow showers Christmas Day. Temperatures fall quickly below freezing on Christmas Night with wind chill values in the single digits. Christmas morning starts off quite with mostly cloudy skies. Skies will begin to clear throughout the day as a stronger cold front and shortwave approach from the northwest once again. There could be a few snow showers associated with this cold front, but not anticipating any accumulating snow at this time. Winds will be breezy from the NW during the day at 20-30mph, with the potential for stronger winds to arrive on Christmas night with 35-45mph gusts mainly in the high terrain and near the waters. High temperatures top out in the upper 30s to low 40s, but will drop like a rock after sunset, possibly below freezing across the entire region by 7 pm. Wind chill values fall to the single digits by midnight with the continued gusty winds. KEY MESSAGE 4...Lower-confidence forecast featuring snow, ice, and rain mix beginning late Friday through the weekend. There are two time frames to monitor for the potential of impactful weather conditions; Friday night into Saturday and then late Sunday into Monday. But, when it comes to exact details, this is where the uncertainty comes into play. First, a low-pressure system moves out of the northern Great Plains and through the Midwest, and ejects off the Mid Atlantic Coast. As the previous forecaster mentioned, there is varying guidance on the overall track and that remains the case as of this update. Because of this, there is a vast spread in the amount of Quantitative Precipitation Forecast, with the 25th percentile of a few hundredths of an inch and the 75th percentile of more than half to two-thirds of an inch. Given the cold air in place, PTypes favor snow, but still time to watch track development. At this time highest probabilities for accumulation are across southwest CT and the NYC metro - where there are 60 to 80 percent probabilites for more than 2" of snow. Sunday afternoon through early Monday could bring another chance for wintry weather, but there is much more uncertainty for this timeframe. These are days 5 and 6, and felt it's important to mention because of the amount of people traveling for the holidays. At this time exact details aren't available because of the varying timing and spread of the guidance, but there is potential for mixed wintry PTypes; snow, ice, and rain mixed. Marine Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Today through Christmas Day A gale warning remains in effect today as a cold front brings gusty NNW winds of 30-40 knots. Rough seas are anticipated today with 7- 10 foot waves offshore, and 4-6 foot waves near shore and in the sounds. Brief reprieve from the gusty winds tonight before stronger winds arrive again for Christmas Day and night. Gale force winds from the NNW once again look possible starting in the late afternoon to early evening. Outlook /Thursday Night through Sunday/... Thursday Night: Strong winds with gusts up to 35 kt. Rough seas up to 11 ft. Slight chance of snow. Friday: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Friday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of snow. Local visibility 1 to 3 nm. Saturday: Winds less than 25 kt. Seas up to 5 ft. Chance of snow. Saturday Night: Winds less than 25 kt. Seas up to 5 ft. Slight chance of snow. Sunday: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain. NOAA Boston MA Office: Watches - Warnings - Advisories CT...None. MA...Wind Advisory until noon EST today for MAZ002-008-009. Wind Advisory until 3pm EST this afternoon for MAZ022>024. RI...None. Marine Gale Warning until 3pm EST this afternoon for ANZ230>237-251. Gale Warning until 5pm EST this afternoon for ANZ250-254>256. |
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