Penobscot Bay Marine Forecast
|Tonight...N Winds 25 To 30 Kt With Gusts Up To 40 Kt. Seas 4 To 7 Ft, Subsiding To 3 To 5 Ft After Midnight. Scattered Showers Early This Evening, Then Isolated Showers Late This Evening.|
|Thu...N Winds 20 To 25 Kt, Diminishing To 15 To 20 Kt In The Afternoon. Seas 3 To 5 Ft.|
|Thu Night...Ne Winds 10 To 15 Kt With Gusts Up To 25 Kt. Seas 2 To 4 Ft.|
|Fri...Ne Winds 10 To 15 Kt, Diminishing To 5 To 10 Kt In The Afternoon. Gusts Up To 25 Kt. Seas 2 To 3 Ft In The Morning, Then 1 Foot Or Less.|
|Fri Night...Ne Winds 5 To 10 Kt, Increasing To 10 To 15 Kt After Midnight. Seas 1 Foot Or Less.|
|Sat...E Winds 10 To 15 Kt, Increasing To 15 To 20 Kt In The Afternoon. Gusts Up To 30 Kt. Seas 2 To 4 Ft. Rain Likely.|
|Sat Night...E Winds 15 To 20 Kt With Gusts Up To 30 Kt. Seas 4 To 6 Ft. Rain.|
|Sun...Se Winds 10 To 15 Kt, Becoming S 5 To 10 Kt In The Afternoon. Seas 3 To 5 Ft. Rain In The Morning, Then Showers Likely In The Afternoon.|
|Sun Night...Sw Winds 5 To 10 Kt. Seas 2 To 3 Ft. A Chance Of Showers In The Evening.|
|Mon...W Winds 5 To 10 Kt. Seas Around 2 Ft.|
|Mon Night...Nw Winds 5 To 10 Kt. Seas Around 2 Ft.|
| Area Forecast Discussion|
...UPDATED National Weather Service Gray ME
718pm EDT Wednesday Oct 27 2021
A strong nor'easter will gradually shift south away from the southern New England coastline tonight. Drying along with diminishing winds are expected tonight. Quieter weather is then expected for both Thursday and Friday before another storm system approaches from the south this weekend which may bring another bout of heavy rain and wind.
Near Term - Until 6am Thursday Morning
Update...Minor changes to reflect latest observational trends. Winds continue to diminish this evening and any occasional gusts that remain will be near the coast. Cold air stratocu is trying to work into the area from the NE...but is being disrupted by terrain upstream. It looks like this will primarily encroach on central ME and Midcoast areas.
Previous discussion...Low pressure continues to drift further from the New England coast at this hour, decreasing the coverage of gusty winds and precipitation over the region.
Through tonight, rain will come to an end; slowly breaking up and moving off the coast. There was a decent convergence band oriented along the ME coast through the afternoon hours as air forced in by high pressure combed through the higher terrain. The strong coastal storm is resilient, not backing away too quick from this influence. These showers have greatly decreased in coverage and intensity over the past hour. While sun has broken out in patches, some clouds may fill back in overnight as it remains a bit breezy.
Short Term - 6am Thursday Morning Through Thursday Night
A beautiful late fall day is set for Thurs. Dry conditions with a bit of a north breeze will remain, but clouds will decrease in coverage through the day.
The biggest takeaway Thursday will be overnight as cold temperatures trickle into the region. Aided by the northerly flow ahead of high pres, winds will lighten and allow for Cold Air Advection to be amplified by rad cooling, particularly in the mtn valleys. Areas of frost will likely creep into the foothills, with patchy frost reaching towards the coast in the coolest spots.
Long Term - Friday Through Wednesday
We'll start out the extended portion of the forecast on Friday, a day that will feature fair weather as high pressure will be in control over New England. However, things begin to change rather quickly Friday night as a closed low moves in from the west.
Latest deterministic and ensemble guidance are in reasonable agreement with the track and timing of the closed low. As the low moves eastward, a warm front will sharpen up just to our south. As this occurs, a +1 to +2 sigma southerly low level jet will develop and overrun the front as PWATs (Precipitable Waters) increase. The result will likely be a period of heavy rain Saturday into Saturday night. It's tough to nail down Quantitative Precipitation Forecast at this point, but a 12 hour period delivering 1-2 inches of rain looks very reasonable given the kinematics, dynamics, and moisture availability at play. We'll have to watch for mesoscale factors that could allow for a little more rain that that, such as upsloping into the Whites as well as any coastal front enhancement. The good news is that the system as a whole continues to chug along and will highly likely not be a multi- day event. Therefore, the rainfall should be manageable but we'll have to keep an eye on trends.
As far as wind potential with this weekend system goes, forecast soundings show quite an inverted low level air mass most locations which should keep the 50 kt LLJ at bay for the most part. The exception could be in the immediate coast where onshore easterly winds may become quite gusty for awhile, but likely below advisory criteria. However, will certainly continue to watch trends.
Thereafter, the rain looks to clear out Sunday with a few showers remaining. Afternoon mixing should allow temperatures to dance around the 60 degree mark.
Early next week looks to feature fair weather.
Gale winds continue tonight, with the bays falling below Gale criteria in the morning. SCAs (Small Craft Advisories) will be needed for the waters once winds slacken late tonight as waves remain elevated through Thurs night, becoming 4 to 6 ft.
The next frontal system brings another round of strong east to southeast winds, potentially gale force, this weekend. Have 10 foot waves forecasted for Saturday at this time for the ocean waters.
NOAA Gray/Portland ME Office - Watches - Warnings - Advisories
Gale Warning until 4am EDT Thursday for ANZ150>154.