Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 211055 AFDGYX Area Forecast Discussion National Weather Service Gray ME 655 AM EDT Wed Oct 21 2020 .SYNOPSIS... 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/... 7am update... 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 observatiosn 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 precip 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. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... Short Term...Mixed bag of conditions out there with LIFR fog at PSM varying to VFR for some inland sites. Expect the variability to continue with the trend being towards IFR holding through the day along the coast and MVFR further inland. Expect LIFR to return for coastal terminals overnight tonight as the onshore flow continues. Front will finally move through allowing a wind shift to westerly to clear conditions out to VFR across the region. Long Term...Conditions likely lower to MVFR and even IFR in fog and stratus later Thursday night and Friday in moistening onshore flow. A cold front crosses by Saturday night which, while having a low probability of producing restrictions, will bring in a drier airmass and a return to VFR. && .MARINE... Short Term... 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. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ SYNOPSIS... NEAR TERM...Curtis SHORT TERM...Curtis LONG TERM...Ekster AVIATION... MARINE... is the U.S. government's official web portal to all federal, state and local government web resources and services.