Penobscot Bay Marine Forecast
| Today...W Winds 10 To 15 Kt, Becoming Sw This Afternoon. Gusts Up To 25 Kt. Seas 2 To 4 Ft. Wave Detail: S 3 Ft At 8 Seconds And Nw 2 Ft At 2 Seconds. |
| Tonight...S Winds 10 To 15 Kt, Becoming Se 15 To 20 Kt After Midnight. Seas 3 To 5 Ft. Wave Detail: S 5 Ft At 7 Seconds And S 3 Ft At 3 Seconds. A Chance Of Snow In The Evening, Then Snow And Rain After Midnight. Vsby 1 Nm Or Less. |
| Sat...S Winds 15 To 20 Kt, Becoming W 10 To 15 Kt In The Afternoon. Seas 3 To 5 Ft. Wave Detail: S 5 Ft At 8 Seconds. Rain And Snow, Mainly In The Morning. Vsby 1 Nm Or Less. |
| Sat Night...W Winds 15 To 20 Kt With Gusts Up To 25 Kt. Seas 3 To 5 Ft. Wave Detail: S 4 Ft At 8 Seconds. |
| Sun...Nw Winds 10 To 15 Kt With Gusts Up To 20 Kt, Becoming Sw Around 5 Kt In The Afternoon. Seas 2 To 4 Ft. Wave Detail: S 3 Ft At 8 Seconds. |
| Sun Night...S Winds 5 To 10 Kt, Becoming Se 15 To 20 Kt With Gusts Up To 30 Kt After Midnight. Seas 2 To 4 Ft. Wave Detail: S 3 Ft At 4 Seconds. |
| Mon...Se Winds 20 To 25 Kt With Gusts Up To 35 Kt, Increasing To 25 To 35 Kt With Gusts Up To 50 Kt In The Afternoon. Seas 5 To 7 Ft. Rain. |
| Mon Night...S Winds 25 To 35 Kt With Gusts Up To 50 Kt. Seas 6 To 9 Ft. Rain. |
| Tue...Sw Winds 25 To 30 Kt. Gusts Up To 45 Kt, Decreasing To 35 Kt In The Afternoon. Seas 6 To 9 Ft, Subsiding To 5 To 7 Ft In The Afternoon. Rain, Mainly In The Morning. |
| Tue Night...W Winds 15 To 20 Kt With Gusts Up To 35 Kt. Seas 5 To 7 Ft. |
| Area Forecast Discussion National Weather Service Gray ME 644am EDT Fri Mar 13 2026 .WHAT HAS CHANGED... Based on observed trends have cancelled the Small Craft Advisories within the Bays while extending the Small Craft Advisory over the outer waters until 11 AM. .KEY MESSAGES... 1. Snow likely tonight into Saturday with light to moderate accumulations. 2. Gusty westerly winds are likely Saturday as low pressure departs the region. 3. Ice jams remain in place across some area rivers but the cooler temperatures should largely allow them to remain in place until early next week. A stronger low pressure system is expected to impact the region late Monday into Tuesday morning, bringing potentially locally heavy rainfall and strong winds. KEY MESSAGE 1 DESCRIPTION... Low pressure is forecast to track thru the Great Lakes and send a warm front lifting into northern New England Fri evening. Forecasts have trended towards more of an occlusion of the primary low pressure and a secondary low trying to take shape in the vicinity of Penobscot Bay. Model guidance even has mid level centers attempting to close off over eastern portions of the forecast area. The end result is longer and stronger forcing for ascent across at least parts of the local area. Now exactly where that mid level deepening occurs will have big impacts for the southward extent of moderate snowfall potential. Currently that gradient is bouncing around central NH into the Casco Bay region. North of that line several inches of snow is possible, along and south of that line is much lower confidence. It could be around an inch and then a dry slot or it could be 2 to 4 inches. Given that we have had a pretty significant melt out and winter is returning it is probably a good idea to remind folks that it is still climatologically winter and I have opted to issue a Winter Weather Advisory for the higher confidence snowfall areas. KEY MESSAGE 2 DESCRIPTION... As low pressure departs the mixing heigheights will increase into Sat afternoon. Forecast soundings suggest that most locations in the forecast area may mix to around 30 to 40 kt. Surface gusts around 30 to 35 mph seems fair if that ends up the case. Winds would increase first across southern parts of the forecast area in the early afternoon, and gradually expand northeastward thru the evening. KEY MESSAGE 3 DESCRIPTION... A deep H5 trough axis is forecast to move east from the Great Lakes region into New England on Monday into Tuesday while becoming negatively tilted. During this time period, a surface low will move near the St. Lawrence River Valley, sending a surface warm front northward as deep south-southeasterly flow brings increasing tropical moisture northward. A trailing cold front will then cross early Tuesday, bringing a wind shift to the west along with the return of drier air. Increasing WAA (Warm Air Advection - the movement of warm air) as the low tracks west of the area will make this primarily a rain event but a brief period of mixed wintry precipitation is possible early Monday morning, mainly from the foothills and points northward. Anomously strong IVT and precipitable water is likely with the ECMWF (European Centre for Medium-Range Weather Forecasts) EFI and especially the NAEFS showing a strong signal for a high moisture content environment with surface dew points potentially climbing into the 50s. These high dew points combined with strong S-SE winds and moderate to locally heavy rainfall will likely lead to rapid snow melt where snowpack remains with temperatures climbing well above freezing even in the mountains. The runoff from the melting snowfall combined with the rainfall and remaining river ice will introduce some flood potential, mainly due to possible ice jams. That being said, river flows remain low given ongoing drought conditions and therefore storage space is higher than usual. NBM and ECMWF ensemble means show a rather high probability (>=70%) for at least 1.00" of rainfall but probabilities for >=2.00" are much lower (~20%). This is mainly due to the short residence time of this system. Another thing that will need to be watched is the potential for strong S-SE winds. Forecast soundings and low-level wind fields show the potential for 80-90 kts at h925, which given mixing could allow for surface gusts between 40-50 mph. Even though trees remain bare, winds out of the SE tend to cause more in the way of issues in our area and therefore power outages are possible. Following this system a return to more seasonable temperatures and mainly dry conditions look likely for the remainder of the week. Marine Gusty northwesterly winds are expected behind a cold front thru the morning. SCAs (Small Craft Advisories) remain in effect for all waters. Winds and seas diminish thru the afternoon. A warm front will lift across the water this evening and overnight with southerly winds increasing in response. SCAs (Small Craft Advisories) are possible for all waters. Winds will turn sharply westerly tonight into Sat. These wind gusts may approach gale force outside of the bays. At least Gale force S-SE winds are likely Monday into Monday night with potential for storm force winds as low pressure tracks west of the waters. Seas of 15-20 ft are possible outside of the bays. Winds and seas will then gradually begin to reduce on Tuesday as winds become westerly. NOAA Gray/Portland ME Office - Watches - Warnings - Advisories ME...Winter Weather Advisory from 11pm this evening to 2pm EDT Saturday for MEZ007>009-012>014-033. Winter Weather Advisory from 11pm this evening to 11am EDT Saturday for MEZ020>022-026>028. NH...Winter Weather Advisory from 11pm this evening to 2pm EDT Saturday for NHZ001>004. Winter Weather Advisory from 11pm this evening to 11am EDT Saturday for NHZ005-006. Marine Small Craft Advisory until 11am EDT this morning for ANZ150- 152-154. |
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