Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 180235 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1035 PM EDT Fri Mar 17 2017 .SYNOPSIS... High pressure with a dry but cold air mass will become centered over northern New England tonight and Saturday and then drift to the northeast Saturday night as low pressure develops south of New England. This low pressure system will pass out to sea southeast of Cape Cod Saturday night and then into the Gulf of Maine Sunday. Across southern New Hampshire and southern and central Maine there is a chance for some light snow late Saturday night and Sunday as the system exits well offshore. Warmer and dry weather is in store for Monday. A cold front will cross the region Monday night followed by a secondary cold front Tuesday night. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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Update... Have updated the grids based on current conditions and latest guidance. Mostly clear skies reign over most of the forecast area except for the far northeastern portions of the county warning area. Dew points continue to run in the single numbers to mid teens. With mainly clear skies and winds finally becoming light, expect radiational cooling overnight. Dropped min temperatures earlier by several degrees in most areas. Do not expect as cold a night as last night with the core of the arctic air no longer over our forecast area, but have trended towards a colder solution, just below MOS Guidance. Would be greater radiational cooling if the snowpack was fresh. Have added freezing spray for tonight into Saturday over the coastal waters. Otherwise, just minor modifications to the dew point, wind and sky cover forecast for this evening. Prev Disc... Canadian high pressure becomes centered over Maine and New Hampshire tonight so clear skies and calm winds are expected. this will allow temps to radiate and become very cold once again. Overnight lows will once again range from 5 below to 5 above zero in the mountains and foothills with readings dropping to the teens to near 20 along the coast.
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&& .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... High pressure remains over the area so a sunny day expected with a cold start to the day. Temperatures will recover nicely and reach into the upper 20s to mid 30s. Winds will remain very light. Saturday night all eyes will be watching the rapidly developing low off the southern New England coast. Models over the last few days were trending to a further southern route leaving us dry. Latest model runs are suggesting a track a little further to the north. This will mean clouds overspreading the area from south to north with some light snow or flurries over southern areas late Saturday night. Using a blend of model pops. Another cold night Saturday night as the offshore storm drags cold air from the north southward into the area. && .LONG TERM /SUNDAY THROUGH FRIDAY/... 500 MB pattern over the CONUS will continue to be somewhat changeable, and not lock into a true +PNA pattern, but will trend toward troughing over the ern CONUS with farily strong blocking downs tream over the ern Atlantic. Although we will some warmer ridges, the troughs will continue to tap into the coldest air near Hudson Bay and will not allow for any extended warming. Overall, temps will run below normal, although Monday/Tuesday will see temps near to slightly above normal. Biggest challenge in the extended will be Sunday as 12Z GFS/NAM deepen develop low outside the 40/70- benchmark and tend to lift it northward across the Gulf of ME on Sunday as 500 mb low closes off over srn New England. This is a somewhat significant change from previous model runs, and would bring some light snow accumulating to coastal areas on Sunday, which could mix with a little rain close to the coast. To complicate matters, the 12Z Euro is experiencing technical difficulties and is indefinitely delayed. The 12Z CMC deepens the system like the American models, but, keeps it further offshore, which may bring some accumulating snow to SE NH and coastal York county. With this in mid have increased pops on Sunday and left them at chc for now, with possible accums of an inch or two for the most part during the day Sunday, However should models trend for a deeper low and/or a track closer to the coast, amounts could increase in later forecasts. Sunday night may see some lingering snow in the mid-coast, but all areas are expected to clear out overnight. Weak ridging builds in Monday and Monday night, with a cold front approaching from the west on Tuesday. Temps should warm to around normal on Monday, generally mid 30s to mid 40s from N to south and partly sunny skies. Tuesday should warm up even further ahead of the cold front with temps in the 40s, and may reach 50 in the warm spots of srn NH and SW ME. The cold front should come through mostly dry, with the exception off SHSN in the mtns late Tue and Tue night, with highs dropping to the 20s to around 30 Wed and Thu. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Short Term...VFR conditions through Saturday night. Long Term...Flight restrictions possible in -SN, especially coastal terminals and KMHT on Sunday. Otherwise VFR. && .MARINE... Short Term...Have added freezing spray to the forecast for tonight into Saturday over the coastal waters. Winds and seas will remain light through Saturday evening. Late Saturday night northeast winds and seas will begin to increase in response to developing low pressure south of New England but will remain below SCA conditions. Long Term...Gales are possible Sunday into Sunday evening, with a period of SCA following into Monday. SCAs are likely again behind a cold front Tue night and Wed. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ Cannon is the U.S. government's official web portal to all federal, state and local government web resources and services.