Casco Bay Marine Forecast
|Tonight...Se Winds Around 5 Kt. Seas 2 To 3 Ft.|
|Mon...Se Winds Around 5 Kt. Seas 2 To 3 Ft. Areas Of Fog In The Afternoon With Vsby 1 To 3 Nm.|
|Mon Night...S Winds Around 5 Kt. Seas 2 To 3 Ft. Areas Of Fog. Vsby 1 To 3 Nm.|
|Tue...S Winds Around 5 Kt, Increasing To 5 To 10 Kt In The Afternoon. Seas 2 To 3 Ft.|
|Tue Night...S Winds 5 To 10 Kt. Seas 2 To 4 Ft.|
|Wed...Sw Winds 5 To 10 Kt, Becoming S 10 To 15 Kt With Gusts Up To 20 Kt In The Afternoon. Seas 2 To 4 Ft.|
|Wed Night...Sw Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 2 To 4 Ft.|
|Thu...Sw Winds 10 To 15 Kt With Gusts Up To 25 Kt. Seas 2 To 4 Ft.|
|Thu Night...Sw Winds 10 To 15 Kt With Gusts Up To 25 Kt. Seas 2 To 4 Ft. Scattered Showers.|
|Fri...Sw Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 2 To 4 Ft. Numerous Showers.|
|Fri Night...W Winds 5 To 10 Kt With Gusts Up To 20 Kt. Seas 2 To 4 Ft. Scattered Showers.|
Area Forecast Discussion|
National Weather Service Gray ME
604pm EDT Sunday May 24 2020
Onshore flow will persist through Monday keeping coastal areas cooler than inland areas. Monday will be quite cool with plenty of clouds. High pressure builds over the East Coast leading to a significant warm up for the middle of the week. Precipitation chances increase late Thursday and Friday with a passing cold front.
Near Term - Until 6am Monday Morning
Update... Have updated the forecast based on current observations and mesoscale models. Onshore flow will continue to gradually moisten the boundary layer overnight. Latest satellite imagery does show areas of low clouds just beginning to enter the Gulf of Maine this evening. Would expect low clouds along and near the coastline later tonight with some patchy drizzle and fog.
A frost advisory will continue for the foothills region where temperatures may drop into the lower to mid 30s by morning.
Prev Disc... Clear skies across the region will persist through sunset. After sunset the onshore flow will moisten the lower atmosphere, allowing low clouds and fog to develop along the coast and gradually creeping inland. By morning expect overcast skies across the coastal plain and clear skies in the north. To the north the clear skies will allow temperatures to again drop into the low 30s and a frost advisory has been issued for the ME/NH border where we saw the coldest temps last night.
Short Term - 6am Monday Morning Through Monday Night
Low clouds will linger along the coast through the day on Monday keeping temperatures in the 50s under overcast skies. Along Penobscot bay may even see some periods of drizzle in the morning. Meanwhile as we move inland to western NH, the White Mountains and along the Canadian border it will be another story as mainly sunny skies allow temps to reach back into the 70s again.
Long Term - Tuesday Through Sunday
Subtropical ridging will stretch from the Azores into the eastern CONUS and up the Mid Atlantic region through mid week. By Thursday, troughing over east central Canada will dig farther south into the eastern Great Lakes and eventually New England.
Increasing warm air advection with warmer than normal temperatures at H9 and H8 will help continue the warm spell in progress. Tuesday will be much nicer than Monday, with temperatures in the upper 70s to mid 80s and partly sunny skies. South winds Tuesday transition to southwesterly flow by Wednesday as high pressure edges southwest and begins to relinquish control over NH and ME. Temperatures in the mid 80s to near 90 degrees are expected Wednesday and Thursday.
Skies will be cloudy by Wednesday evening areawide, with increasing chances for precipitation as a boundary shifts south out of Canada. Isolated showers and perhaps a storm or two will develop mainly over the mountains both Wednesday and Thursday, closer to a cold front. The better forcing will remain north of the Canadian border until Friday, when models are currently bringing it south. The front and the approaching upper trough will spread widespread showers and thunderstorms across the region Friday.
Friday will be slightly cooler but still warm in the mid 70s to mid 80s. PWATs (Precipitable Waters) will also be high, with warm rain processes dominating any convection. This may lead to localized heavy rain along the slow moving boundary. Instability and shear should be enough for general thunderstorms in a broken line as the front moves through, but not expecting anything strong.
Temperatures will be a bit cooler by the end of the week with the increased cloud cover and widespread showers. The front is currently forecast to move offshore Saturday. Somewhat cooler and drier air arrives behind the front for next weekend with highs dropping into the 60s north to low 70s south.
Onshore flow will result in increasing cloud cover, with fog and possible drizzle developing. Expect the cloudy, cool and foggy conditions to continue through the day tomorrow.
Long Term...Mainly quiet on the waters with high pressure nearby. SW winds will increase to near SCA (Small Craft Advisory) midweek for the outer waters as a frontal system over southern Canada increases the pressure gradient over the waters.
NOAA Gray/Portland ME Office - Watches - Warnings - Advisories
ME...Frost Advisory from midnight tonight to 7am EDT Monday for MEZ007-012-033. NH...None. MARINE...None.