Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 142241 AFDGYX Area Forecast Discussion National Weather Service Gray ME 541 PM EST Thu Dec 14 2017 .SYNOPSIS... High pressure builds in from the south overnight, and shift east on Friday. Weak low pressure to our north and south will provide clouds, and maybe a few snow showers or flurries Friday night into early Saturday. High pressure builds in on Sunday and starts a warming trend. Although slightly warmer, several fast moving systems could provide some light precipitation early to mid nest week. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... 540 PM Update...Little change to the going forecast. Very cold weather continues to be expected overnight with little in the way of cloud cover. A few areas will decouple overnight resulting in lows below zero in spots - especially with snowcover now in place. Previously... High pressure will build in from the south later tonight, but should see the breezy conditions continue through at least sunset, with mainly clear skies overnight. Main question will be if and how quickly sfc areas can decouple later after the winds diminish. Looks like some radiational cooling will be possible during the latter part at most locations, and forecast lows currently reflect that, dropping into the single digits below zero in the mountains, and the single digits above zero elsewhere. Even with some lingering winds air aloft is still plenty cold. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... Friday should start off sunny, and generally remain on the sunny side through most of the day before clouds start to move in from the SW. With the sfc ridge moving slowly east sfc flow will be light, and despite a bit of SW flow aloft, the lack of mixing will keep highs on the colder side, and similar to Thursday, generally in the teens N, to the low to mid 20s in the S. Weakening sfc low moving east along the St. Lawrence valley will transition energy to developing coastal low well offshore. This will spread clouds across the region overnight Friday. Scattered SHSN can be expected in the north, and there is the potential for some sct SHSN to the SE as the coastal low develops as well, but overall any snow will be light with a dusting at best. Lows will range from 5-10 above in the mtns, to 15-20 on the coast. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Backside trough crosses the area on Saturday and could trigger some light mountain snows. It will be warmer, but still cold, with highs in the 20s and low 30s. High pressure builds in from the northwest Saturday night and Sunday with slightly colder weather. Cut off upper low ejecting out of northwest Mexico will track northeast across the country this weekend, getting squashed by a ridge in the southeast US as it does so. By the time its remnants get into our area on Monday there may only be some clouds left with it, but there will still be a chance of light snow. Any accumulation will be light as there is not a good moisture connection with it. Broader upper trough arrives on Tuesday with another chance of precipitation as it moves through. This one has a better moisture connection and may pull in some warm air ahead of it. Thus it may actually be warm enough for rain for much of the area, but expect a return to colder conditions behind the cold front which moves through Tuesday night. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... Short Term...Mainly VFR through Fri night. Long Term...Should see some MVFR ceilings northwest of the mountains with some light snow on Saturday but VFR elsewhere. VFR areawide by Sunday. Could see MVFR and light snow area wide on Monday but confidence is low and accumulations will be light. && .MARINE... Short Term...Surge of west winds behind a cold front is occuring late this afternoon, and will likely continue into evening at least, so SCA will hold as for now. May see winds drop off in the bays by midnight or so. May need SCA again late Fri night. Long Term...May see advisory level wind gusts late Saturday and Saturday night behind a cold front. High pressure over the area keeps conditions quiet through Monday. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 7 AM EST Friday for ANZ150>154. && $$ NEAR TERM UPDATE...Ekster

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