Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 221709 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1209 PM EST Wed Nov 22 2017 .SYNOPSIS... Low pressure will track southeast of the region today, bringing a period of mostly rain to the area. A changeover to snow before ending will be found in the mountains. This low will pull a cold front across the area this evening. Thanksgiving will mainly sunny but chilly, with a warming trend Friday into Saturday. Another cold front crosses the area on Sunday and could bring some rain or snow showers, with another blast of cold air expected early next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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NOON...Tweaking everything based on current obs, following the HRRR closest thru the evening, although it may be an an hour or so behind for timing of precip, but should see rain ending by late afternoon to early evening from SW to NE. Only, sub- freezing spot at midday is K1P1, but it has begun to precipitate there as UP, and this should bump it abv freezing shortly. Will see rain mix with snow in the mountains this afternoon, but thinking any light accums will likely occur above at least 2000 ft. 920 AM...HAve tweaked a few things in the forecast, mostly dealing with p-type this AM, but some adjustment to temps later today as well. While I did not remove FZRA, I did back it off somewhat to only include the sheltered valley regions that are currently below freezing. I think the chc is very limited, and even if any place does see FZRA it will be very short-lived. as the precip will mix down warmer air. Also, some of these colder spots could actually see precip start as as snow instead FZRA, with colder air loft across the NW zones, and it slowly shifting east this morning. Otherwise look for the rain to continue moving in from the S and shifting east along the coastal plain this morning into early afternoon. It should end from SW to NE later today, first in srn NH around mid-afternoon, and by early evening in the ern zones around the mid-coast and the Penobscot valley. Previously...Input latest obs data and made a few adjustments to lower temps for next few hours. Clouds have overspread the area and the two areas of rain are now approaching, one from the west associated with the cold front and the other from the south associated with the developing offshore system. Temps rather cold and below freezing over most areas at this time but should warm to above freezing before any onset of rain. Can`t rule out a few pockets of light freezing rain briefly at the onset over the mountains and a few other inland locations mid morning. Any pockets of freezing rain will quickly come to an end by late morning as surface temps warm well above freezing. A fast moving upper trof with an associated cold front will approach from the Great Lakes today. Ahead of this trof a warm moist south to southwest flow will develop. Overrunning light rain will develop by later this morning ahead of the trof and may even see a brief mix at the onset in the mountains due to the initial cold morning temps. A weak wave will develop southeast of New England and may enhance some of the precipitation along the immediate coast this afternoon. Qpf amounts from this system will be light...generally less than a quarter inch for most areas except .50-.75 inches along the immediate coastal areas due to the developing offshore system. During the mid to late afternoon hours enough cold air may make its way into the mountains to change any precipitation to snow showers before ending in those areas. High temps will be generally in the 40s.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... The trof and associated cold front moves rapidly offshore this evening bringing an end to the precipitation over southern and coastal areas, a brief mix may occur before ending. Much colder temps will follow behind the front overnight with morning lows expected to dip in the teens in the mountains and 20s elsewhere. High pressure builds across the region Thursday with mostly sunny skies but cold temps with highs expected to be in the 30s except lower 40s along the coast and southeast NH. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... The weather pattern will remain at a fast clip through the extended despite partial blocking downstream. Thanksgiving night clouds will be on the increase as the 5H closed low over eastern Canada pivots ENE with time. Snow showers will be possible near the international border overnight as a backdoor front moves through. This will push cooler and drier air into New England. Despite a chilly start, SW winds later in the day should result in highs ranging from the mid 30s north to mid to upper 40s along the coast. Friday night will be chilly with clouds still hanging on over the higher terrain. As one upper low moves towards Greenland another will swing south to take its place. This system will be more meridional and will trigger snow and rain showers through the weekend. The changeover to snow will be elevation-based for the most part. Relatively little moisture will be available and only light QPF is expected. The region will be in the warm sector for much of Saturday, and downsloping winds will make for warm temperatures with many spots in the 50s Saturday. Upper 30s to mid 40s are more likely Sunday. Behind the weekend system temperatures will drop again towards more normal values. More zonal flow aloft and high pressure at the surface will make for a quiet beginning to the work week. Additional showers are likely for next Tuesday/Wednesday as we become more engaged in fast southwest flow. Again we could see some very warm temperatures- in the 40s and 50s for highs areawide- as northern New England stays locked in the warm sector. && .AVIATION /17Z WEDNESDAY THROUGH SUNDAY/... Short Term...Conditions lowering to IFR later this morning and afternoon across the area. Conditions improve to VFR behind the frontal passage by later this evening. VFR conditions Thu and Thu night. Long Term...Some locations may see periods of MVFR conditions in SHSN/SHRA Saturday and Sunday. && .MARINE... Short Term...A SCA will continue over the eastern outer waters for seas this morning and then later today through Thu for gusty winds and seas. For the outer waters area south and east of Portland winds and seas will increase to SCA conditions later today through Thursday. Over the bays conditions should remain below SCA conditions through Thu. Long Term...Both Saturday and Sunday will see periods of winds reaching or exceeding SCA criteria, although these times may not be adjacent temporally. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 7 PM EST Thursday for ANZ150-152. Small Craft Advisory from 4 PM this afternoon to 7 PM EST Thursday for ANZ154. && $$ SYNOPSIS... NEAR TERM...Cempa/Marine SHORT TERM...Marine LONG TERM...Hanes AVIATION... MARINE... is the U.S. government's official web portal to all federal, state and local government web resources and services.