Casco Bay Marine Forecast
|Today...Ne Winds 10 To 15 Kt, Diminishing To 5 To 10 Kt Late This Morning, Then Becoming E Early This Afternoon, Becoming Se Late. Seas Around 2 Ft. Patchy Drizzle This Morning. Patchy Fog This Morning With Vsby 1 To 3 Nm.|
|Tonight...Sw Winds 5 To 10 Kt. Seas Around 2 Ft. Areas Of Fog. Vsby 1 To 3 Nm.|
|Thu...Nw Winds 5 To 10 Kt, Becoming Se In The Afternoon. Seas Around 2 Ft. Areas Of Fog In The Morning With Vsby 1 To 3 Nm.|
|Thu Night...E Winds Around 5 Kt. Seas 2 To 4 Ft.|
|Fri...Se Winds 5 To 10 Kt. Seas 3 To 5 Ft.|
|Fri Night...S Winds 5 To 10 Kt. Seas 3 To 5 Ft.|
|Sat...Sw Winds 5 To 10 Kt. Seas 3 To 5 Ft.|
|Sat Night...N Winds 10 To 15 Kt. Seas 3 To 5 Ft.|
|Sun...N Winds 10 To 15 Kt, Diminishing To 5 To 10 Kt In The Afternoon. Seas 3 To 5 Ft.|
|Sun Night...E Winds 5 To 10 Kt. Seas 2 To 3 Ft.|
| Area Forecast Discussion|
...UPDATED National Weather Service Gray ME
926am EDT Wednesday Oct 21 2020
Today will be cooler as a cool dense air mass will hold across much of the forecast area. However, most locations will remain dry. High pressure then builds into the region for Thursday and Friday before a cold front crosses through on Saturday afternoon. Cooler weather will follow behind the front before another series of disturbances impact the area early next week. Swells will increase late this week and into the upcoming weekend as Tropical Storm Epsilon passes well offshore.
Near Term - Through Tonight
926 am Update: Lowered temperatures over much of southern Maine into southern New Hampshire per cold air damming setup and no real prospect of sun today. Have also extended drizzle wording south of the mountains through the remainder of the morning. 12Z GYX RAOB (Radiosonde Observation or Upper-Air Observation) shows saturated column all the way to H8 with a nearly perfect setup for drizzle given increasing dewpoints with height and ample shear at the top of the moisture layer. Have some concerns that drizzle may even last into early afternoon...but should wane with limited daytime mixing. Will continue to monitor trends. No other significant changes at this time.
8am Update: Minor update to add drizzle to the forecast in the areas of fog given multiple reports of drizzle and now some light rain at the ASOS/AWOS sites. No other changes attm.
7am have increased Patchy fog coverage to extend throughout NH south of the Whites in keeping with surface obs. Quite a bit of fog out there with visibility variable from 5SM to less than 1SM.
Prev disc... Satellite imagery and surface observation reveals some dense fog through the Gulf of Maine and extending into extreme southeast NH. Expect easterly flow to shift southeasterly as warm air advection continues ahead of a cold front located to our west across lake Ontario and into the St. Lawrence Valley. This onshore flow will keep low clouds and fog in place through most of the day along the coastal plain. While overnight temperatures remain quite mild, int he upper 50s, will see little change during the day with highs only in the 60s. A few scattered showers are possible, mainly along the Canadian border as the front slowly approaches late in the day.
Short Term - Thursday
Onshore flow continues overnight with accompanying fog and low stratus settling in for the night. Have gone with widespread 1SM fog for the moment, but dense fog is possible, especially in the coastal zones. The front continues its slow approach, however expect most of the precipitation to lift northwards as the low moves out across the north shore of the St. Lawrence.
Winds will come around to westerly Thursday morning, allowing the moist airmass to finally move out along the coast. With this expect to see the warmest temperatures on Thursday as high reach a good 10-15 degrees above average for this time of year, exceeding 70 across southern NH.
Long Term - Thursday Night Through Tuesday
The long term period starts off Thursday night with surface high pressure parked over southern Quebec that will extend southward into New England allowing for fair weather across our forecast area. This high will move off the coast late in the day later Thursday night and Friday allowing for a southeasterly return flow to set up. Have increased clouds some for this time period as the return flow will be moist and act in conjunction with deeper warm air advection. Can't rule out a shower or two across western zones later Thursday night also.
A short wave trough will approach from the west later Friday and Friday night helping to push a cold front eastward. This front should cross the forecast area Saturday afternoon perhaps with a few showers, but a good portion of the CWA has the potential for remain dry. Temperatures will rise well into the 60s Saturday with a few 70 degree readings expected in the south. Thereafter, high pressure builds in for Sunday with cooler but fair weather.
Another warm front approaches Sunday night. Various members of the 00z model suite indicate that Monday and Monday night will hold the best chances for rain with the warm front, and then with the trailing cold front. Wouldn't be surprised if one or two locations see a thunderstorm out of this system.
Fairly quiet over the waters in terms of winds and seas, with areas of dense fog over much of the Gulf of Maine. What remains of a trailing cold front will cross the waters early on Thursday, making way for the northwards progression of Tropical Storm Epsilon. While the storm will remain well out to sea, expect to see seas begin to build late Thursday as long period swell from the system begins to approach our area.
Long Term...Winds do not appear to be much of an issue Thursday night through the weekend. However, periods of fog will be likely. Much of the period will feature 5-7 ft long period swells from tropical system Epsilon as it moves well east of the New England coast over the weekend.
NOAA Gray/Portland ME Office - Watches - Warnings - Advisories
ME...None. NH...None. MARINE...None.