Casco Bay Marine Forecast
| Today...Sw Winds 5 To 10 Kt, Increasing To 10 To 15 Kt With Gusts Up To 25 Kt This Afternoon. Seas 2 To 3 Ft. A Slight Chance Of Snow Showers This Afternoon. Vsby 1 Nm Or Less Early This Afternoon. |
| Tonight...Sw Winds 10 To 15 Kt, Becoming W 5 To 10 Kt After Midnight. Gusts Up To 25 Kt. Seas 2 To 3 Ft. A Chance Of Snow Showers After Midnight With Vsby 1 Nm Or Less. |
| Sun...N Winds 5 To 10 Kt, Increasing To 15 To 20 Kt With Gusts Up To 25 Kt In The Afternoon. Seas Around 2 Ft. A Chance Of Snow Showers. Vsby 1 Nm Or Less. |
| Sun Night...Nw Winds 15 To 20 Kt With Gusts Up To 30 Kt. Seas Around 2 Ft. |
| Mon...Nw Winds 15 To 20 Kt With Gusts Up To 30 Kt. Seas 2 To 3 Ft. |
| Mon Night...W Winds 10 To 15 Kt, Diminishing To 5 To 10 Kt After Midnight. Seas 2 To 3 Ft. |
| Tue...W Winds 5 To 10 Kt. Seas Around 2 Ft. |
| Tue Night...Sw Winds 10 To 15 Kt With Gusts Up To 20 Kt, Increasing To 15 To 20 Kt With Gusts Up To 30 Kt After Midnight. Seas 2 To 3 Ft. |
| Wed...Sw Winds 15 To 20 Kt With Gusts Up To 30 Kt. Seas 2 To 4 Ft. |
| Wed Night...W Winds 15 To 20 Kt With Gusts Up To 25 Kt, Diminishing To 5 To 10 Kt After Midnight. Seas 2 To 4 Ft. |
| Area Forecast Discussion National Weather Service Gray ME 1240am EST Sat Dec 13 2025 Synopsis A coastal storm passes well out to sea tonight into Sunday but may be close enough for a little light snow along the coast and over southern New Hampshire. That will be followed up by another very cold Monday with gusty winds. Expect the wind chills to remain in the teens and single digits. Near Term - Through Today Winds continue to ease through the overnight hours as a ridge axis of high pressure builds in from the west. Winds likely dont go completely calm in most spots until near sunrise, if at all. At the same time, clouds begin to overspread from the west, which limits the radiational cooling effects through daybreak. During the daytime today, an elongated shortwave pivots through northern New England around a more broad trough. This brings just enough instability and moisture to bring some intermittent snow showers during the late morning and afternoon hours. A little bit more moisture feeds into the MidCoast off the ocean, so a steadier burst of light snow may bring up to about a half inch here. Other than similarly light accumulations across the higher terrain, no accumulation is expected elsewhere. Short Term - Tonight Through Sunday An Alberta Clipper slides south of New England tonight and tomorrow, and begins to develop into a strong ocean storm as it moves out to sea. Clouds from this developing system keeps temps warmer tonight, with lows mainly in the teens to low 20s. Along the coast, just enough moisture may extend from the western edge of the developing system to bring some periods of light snow along the coastal plain late tonight and tomorrow. Accumulations would remain very light, with little more than a coating expected. There is also a decent chance that this moisture remains entirely offshore, so we'll have to monitor just how far west the moisture actually extends as the system is developing. As the system continues to move out to sea and strengthen, an increasing northerly wind develops for the afternoon and evening hours tomorrow. The next shot of cold air begins to move in on this northerly wind tomorrow, with highs topping out in the 20s to near 30. Temps steadily fall during the afternoon hours as the Cold Air Advection increases. Long Term - Sunday Night Through Thursday The next shot of arctic air pushes in overnight Sunday, leading to frigid temperatures Monday morning and blustery conditions through the day. Lows are forecast to mainly range from around zero across portions of the north, to the upper single digits and lower teens south. Strengthening westerly winds will lead to widespread below zero wind chills Monday morning with some double digit readings below zero across the north. Some low probability snow chances may hang around into Monday morning near the coast and through the day across the mountains in the upslope regime. It should stay cold and windy through the day on Monday with highs only rising into the upper single digits across portions of the north, to the lower 20s south. With winds remaining gusty through the day, wind chill values will likely remain below zero north and only rise into the single digits above most elsewhere. Tuesday morning lows will be very similar to Monday but with less wind. The warmup then begins in earnest on Tuesday afternoon as highs rise into upper teens and lower 20s north, to the upper 20s and lower 30s south. By Thursday, the NBM has forecast highs ranging from the low to mid 30 north, to the low to mid 40s south. There are also some signals in the long term ensembles that these warmer temperatures could extend into Friday and the weekend. Regarding precipitation chances, a couple of weak shortwave troughs will approach on Monday night and again Wednesday night. Low chances of light snow are possible Monday night with low chances of light rain or snow mid-week. A stronger system with more widespread chances of precipitation looks possible to end the work week but details remain unclear this far out. Marine Short Term SCA (Small Craft Advisory) conditions ease through daybreak. Another period of SCA (Small Craft Advisory) conditions is likely this afternoon and tonight across the outer waters in southwesterly flow. A developing ocean storm tracks south of the Gulf of Maine tomorrow, with northerly winds increasing to SCA (Small Craft Advisory) levels by tomorrow afternoon. Long Term SCA (Small Craft Advisory) conditions are likely late Sunday through Monday. Northwest winds increase as the low deepens over the Canadian Maritimes and there may also be a period of gales. Conditions improve Tuesday before a cold front approaches and crosses mid week, likely bring at least SCA (Small Craft Advisory) conditions and possibly gales. Another frontal system is then possible late in the week. NOAA Gray/Portland ME Office - Watches - Warnings - Advisories ME...None. NH...None. Marine Small Craft Advisory until 4am EST Saturday for ANZ150-152- 154. |
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