Nantucket Sound Marine Forecast
| Today...Nw Winds Around 10 Kt. Seas Around 2 Ft This Morning, Then 1 Foot Or Less. Wave Detail: Nw 1 Foot At 3 Seconds And Se 1 Foot At 9 Seconds. |
| Tonight...Nw Winds 10 To 15 Kt. Seas Around 2 Ft. Wave Detail: N 2 Ft At 3 Seconds And Se 1 Foot At 9 Seconds. |
| Tue...Nw Winds 10 To 15 Kt. Seas Around 2 Ft In The Morning, Then 1 Foot Or Less. Wave Detail: N 2 Ft At 3 Seconds And Se 1 Foot At 9 Seconds, Becoming N 1 Foot At 3 Seconds And Se 1 Foot At 9 Seconds. |
| Tue Night...Nw Winds 10 To 15 Kt. Seas Around 2 Ft. Wave Detail: N 2 Ft At 4 Seconds And Se 1 Foot At 9 Seconds. |
| Wed...W Winds 10 To 15 Kt, Becoming Sw With Gusts Up To 20 Kt In The Afternoon. Seas Around 2 Ft. Wave Detail: Nw 2 Ft At 4 Seconds And Se 1 Foot At 9 Seconds. A Chance Of Showers In The Afternoon. |
| Wed Night...Sw Winds 20 To 25 Kt With Gusts Up To 30 Kt. Seas 2 To 4 Ft, Building To 4 To 6 Ft After Midnight. Wave Detail: Sw 4 Ft At 4 Seconds And N 1 Foot At 4 Seconds, Becoming Sw 4 Ft At 5 Seconds And S 4 Ft At 8 Seconds. Showers. |
| Thu And Thu Night...W Winds 25 To 30 Kt With Gusts Up To 35 Kt. Seas 5 To 7 Ft. Showers. |
| Fri...Nw Winds 25 To 30 Kt. Seas 4 To 6 Ft. A Chance Of Snow Showers. |
| Fri Night...Nw Winds 20 To 25 Kt. Seas 3 To 5 Ft. 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. |
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Area Forecast Discussion National Weather Service Boston/Norton MA 701am EST Monday Dec 2 2024 Synopsis Below normal temperatures and mainly dry conditions early this week, with the exception of some offshore ocean effect rain/snow showers. Next chance for precipitation comes late Wednesday through Thursday, bringing rain or light snowfall. An even colder airmass moves in Friday and into the weekend, likely with the coldest air of the season thus far. Near Term - Until 6pm This Evening Relatively quiet weather continues. Mainly clear skies across southern New England, except towards the west slopes of the Berkshires. Some of these clouds may spill over the Berkshires to the east slopes at times today. Mainly brought temperatures back in line with observed trends. Previous Discussion... Dry air in place across southern New England. Synoptic pattern has shifted just enough with a low pressure over far eastern Canada, and a high pressure over TN. This will shift winds move from the NW, which would drive any ocean-effect showers farther offshore. Not expecting as many clouds today across most of southern New England, with perhaps the exception of the outer Cape late today. Below normal temperatures continue, but not quite as windy today. Short Term - 6pm This Evening Through 6pm Tuesday Turning even colder tonight, Expecting mainly clear skies for most of southern New England with rather light winds, nearly ideal radiational cooling conditions. Low temperatures in the teens to lower 20s away from the immediate coast should be common. Despite the sunshine Tuesday, below normal temperatures will persist. Cloud cover will be complicated. NW winds and the colder air should generate ocean-effect clouds. A subtle shift of only 10 degrees in wind direction can either drive these clouds across the outer Cape, or keep them just offshore. At this time, favoring partly to mostly cloudy conditions tonight into Tuesday across the outer Cape. Long Term - Tuesday Night Through Sunday Key Messages: * Continued below-normal temperatures through the end of the week, trending even colder for the weekend. * Clipper system will bring light snow accumulations to the interior and rain/snow mix to the coast. Weak ridge moves through the region Wednesday sandwiched between two shortwave systems. Winds turn WSW ahead of the incoming shortwave and strong clipper system over the Great Lakes. Temperatures warm into the upper 30s to low 40s Wednesday afternoon with WAA. Precipitation chances don't start increasing until Wednesday night, but skies will turn mostly cloudy in the afternoon due to the WAA. Confidence continues to increase that a clipper system will bring light accumulating snow to the interior Wednesday night into Thursday. The GFS (Global Forecast System) and EURO ensembles continue to show high probabilities of 70-90% for 1 inch of snow across the interior, with low to moderate probabilities of 10-40% for 3 inches of snow. The deterministic NAM, GFS, and EURO also show similar outcomes with 1-3 inches of positive snow depth change across the interior. Closer to the coasts, WAA (Warm Air Advection - the movement of warm air) will cause surface temps to rise above freezing. There may be a rain/snow mix with the onset of precipitation Wednesday night, but it will likely transition to all rain by Thursday morning. Winds begin to ramp up Wednesday night as a southwest 35-40 knot 925mb LLJ moves over the coastal waters along with a very tight pressure gradient. Winds start from the SW Wednesday night but turn west Thursday with the cold frontal passage. Gusts of 30-40 mph are possible Wednesday night into Thursday, with the NBM showing low probabilities of reaching Wind Advisory criteria of 46 mph. Forecast confidence breaks down beyond Friday with large spread among the deterministic guidance sources. Temperatures behind the clipper system look to remain unseasonably cold, with highs in the 30s and lows in the teens Friday into the weekend. Marine Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Winds continue to diminish today. Expecting relatively tranquil boating conditions for this time of year. Slight risk for some rain showers across the outermost coastal waters tonight, and again Tuesday afternoon. Outlook /Tuesday Night through Friday/... Tuesday Night: Winds less than 25 kt. Chance of rain showers, slight chance of snow showers. Wednesday: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain showers. Wednesday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Rain showers. Thursday: Strong winds with gusts up to 35 kt. Rough seas up to 14 ft. Rain showers. Thursday Night: Strong winds with gusts up to 35 kt. Rough seas up to 14 ft. Chance of rain showers, slight chance of snow showers. Friday: Strong winds with gusts up to 35 kt. Rough seas up to 11 ft. Slight chance of snow showers. NOAA Boston MA Office: Watches - Warnings - Advisories CT...None. MA...None. RI...None. Marine None. |
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