Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 272233 AFDGYX Area Forecast Discussion National Weather Service Gray ME 533 PM EST Sun Nov 27 2016 .SYNOPSIS... A narrow ridge of high pressure will build in from the west overnight and Monday. High pressure will crest over the area Monday night before shifting east. A warm front will approach from the southwest on Tuesday and will stall over southern New England Tuesday night. Low pressure will approach from the west on Wednesday and will drive a cold front through the region Wednesday night. A trough of low pressure will linger over northern New England and southern Quebec Thursday through Friday. High pressure will build south of the region Friday night through Saturday. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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UPDATE...Have updated the grids based on latest observations and set of mesoscale models. Bands of mainly light rain showers continue over the Midcoast region north and east of Portland. This precipitation will gradually dry up during the late evening hours, changing to light snow showers in many areas before dissipating. Mesoscale models indicate these light bands of precipitation will exit the Midcoast between 00Z and 03Z. Made minor adjustments to dew point and cloud forecast, as well as kept showers in the grids for a few more hours east of the Kennebec River Valley. PREV DISC... Low pressure will head northeast through the maritimes overnight as high pressure builds in from the west. Looking for any lingering showers in eastern zones to come to an end this evening. Should see variable cloudiness downwind of the mountains this evening before clearing sets in after midnight. In the north... upslope flow and abundant low level moisture will kep clouds and scattered snow showers in the forecast overnight with clearing toward daybreak. Lows will range through the 20s from North to south.
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High pressure will continue to build in from the west on Monday. Looking for mostly sunny skies with highs ranging through the 30s north and lower to mid 40s south. Quiet weather will continue Monday night as high pressure crests over the region before shifting east. After a mostly clear evening expect increasing clouds after midnight as a warm front approaches from the southwest. Lows will dip into the mid teens to lower 20s north and will range through the 20s south.
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&& .LONG TERM /TUESDAY THROUGH SUNDAY/... A broad upper low centered over the northern plains will eject a short wave northeast toward New England Tuesday spreading a warm air advection pattern aloft in advance with rain or mixed precipitation into mostly southern and central areas by Tuesday afternoon. PTYPE further north snow or a mix is expected. Any mixed precipitation will change to rain over all areas except in the mountains by later Tuesday and into Tuesday night. The mountains may receive several inches of snowfall before mixing or changing to rain late Tuesday night. Models differ by a few degrees on extent of warm air reaching the mountains. The system exits by Wednesday morning but not much clearing expected as a front remains stalled across the area. Also, another more significant system will rotate around the base of the Midwest upper low and will move rapidly northeast toward New England spreading rain into the region by late Wednesday through Wednesday night. This will be a warmer system and with warmer boundary layer temps and temp profiles aloft, precipitation should be all rain. By Thursday the system exits and a colder west to northwest flow develops in its wake. This colder northwest flow that develops at the surface and aloft will likely persist into the weekend with scattered snow showers in the mountains but dry elsewhere. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... Short Term...VFR overnight with areas of MVFR ceilings in the mountains. VFR Monday and Monday night. Long Term...Conditions will become MVFR to IFR Tuesday with rain or mixed precipitation spreading from southwest to northeast during the day. At this time, the most likely precipitation type at all TAF sites is rain, but there could be a period of snow or mixed precipitation at KHIE and KAUG. Conditions improve a bit on Wednesday, but more precipitation will move in Wednesday night into Thursday. This should begin as mostly rain, but could transition to snow showers from northwest to southeast before ending on Thursday. && .MARINE... Short Term...Continuing sca`s through midnight. Long Term...Southeast winds increase to near SCA levels ahead of an approaching weak low pressure system that will move through the Gulf of Maine Tuesday night. Winds diminish on Wednesday behind the departing low, but pick up again Wednesday night in advance of the next, stronger system. SCA winds/seas are more likely with this system Wednesday night into Thursday. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until midnight EST tonight for ANZ150>152- 154. && $$ CANNON is the U.S. government's official web portal to all federal, state and local government web resources and services.