Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 241440 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1040 AM EDT Sat Sep 24 2016 .SYNOPSIS... An area of high pressure moving out of central Canada will bring cooler temperatures and drier air to the region through Sunday. Many towns in the area may see their first frost or freezing temperatures tonight or Sunday night. Gradually moderating temperatures are expected Monday before another approaching cold front brings the threat for showers for Monday night and Tuesday. Cool weather will return for Wednesday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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1030 AM...some fine tuning of grids, with most notable changes to wind for today. Mainly it was brought down across the board, although will still winds of 10 mph, with gusts to near 20 mph, not quite as high as previously thought as will have to wait for energy to drive equatorward in trough to our north to deep sfc low over the maritimes, which will come this evening, but will be less noticeable tonight due to limited mixing. Otherwise most places should see mostly sunny skies, although could see more clouds in the mtns this afternoon, with highs around normal, upper 50s to around 60 in the mtns, and mid to upper 60s in the south. Previously...Clouds continue to move south through southern New Hampshire and extreme southwest Maine early this morning as high pressure continues to push into the area. By morning, skies should be mostly sunny across the region...although a patch of high clouds may catch the mountains of Maine. With sun and colder air advecting into the area, winds will become gusty this afternoon. The unstable conditions and upslope flow will lead to a bit more cloudiness in the mountains during the afternoon with clouds gradually diminishing toward the coast. Temperatures today will reach the upper 50s to near 60 in the mountains today and in the upper 60s in southern areas and along the coast.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... With cold high pressure over the area, temps will drop to freezing in the valleys of Coos County and parts of the western Maine mountains a freeze warning is being issued for NH1-2 and ME7-8 zones. There is still some uncertainty based on wind...any fog development...and moisture rotating around the upper low to the northeast. A frost advisory is being issued surrounding the Warning as temps will drop into the mid 30s. Greatest concern in the advisory will be sheltered valleys as elevated areas will likely maintain some wind. Sunday should be partly to mostly sunny across the region with high temperatures mainly in the lower 60s along the coast. Winds will again become a bit gusty during the afternoon with gusts of 15 to 20 mph. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... In the next few days anomalously meridional pattern will shift east/northeast with time. The upper low currently over eastern Canada will shift towards Iceland while high amplitude ridging builds in ahead of another cutoff low. Behind this ridging another bowling ball upper low (currently over the 4 corners region) will be headed our way. Large Canadian high pressure system will dominate the surface weather pattern through Monday night keeping things dry. Much drier and the coldest air of the season will move into New England Sunday night into Monday morning. Most of the guidance is hovering around 850mb temperatures right around 0 degrees C for most of ME and NH. Lighter winds during this time along with clear skies will boost radiational cooling processes. All this will translate to the coldest night we have seen so far with overnight lows in the upper 20s/lower 30s across the north with some of the colder air also draining into the Connecticut River Valley. Mid to upper 30s to near 40 degrees will be more likely closer to the coast. Will need to issue freeze advisories and expect to see widespread frost. During the day Monday cirrus begins to move in as a warm front approaches from the west. Temperatures will be in the 60s with southerly winds in place. The warm front sweeps through late Monday followed quickly by a cold front as the second upper low nears and becomes stationary. This will bring scattered showers to the region. Confidence immediately after this point wanes with model solutions differing. Blocking downstream will keep the upper low over the eastern U.S. The cold front which moved offshore Monday may move north again later in the week bringing rain to southern areas. High pressure over Canada will attempt to hold strong over northern New England. At this point it is hard to tell the exact locations of all these features, and thus the mid to late week weather. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... Short Term...VFR conditions expected. Winds will gust to 20 to 25 mph this afternoon at many of the airports. Long Term...VFR conditions Sunday and Monday. There will be patchy valley freezing and non-freezing fog Sunday and Monday mornings which may briefly bring HIE and LEB down to IFR. Otherwise rain on Tuesday may be heavy at times and cause MVFR ceilings and visibility before improving late in the day. Fog will be likely Wednesday morning before conditions return to VFR. && .MARINE... Short Term...Winds and seas expected to be below sca criteria although some gusts may approach 25 kts this afternoon and evening. Long Term...Winds and seas will likely approach or exceed small craft criteria Tuesday. Later in the week winds may be near criteria again as a frontal boundary wavers in the area. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...Freeze Warning from 2 AM to 8 AM EDT Sunday for MEZ007-008. Frost Advisory from 2 AM to 8 AM EDT Sunday for MEZ009-012-013. NH...Freeze Warning from 2 AM to 8 AM EDT Sunday for NHZ001-002. Frost Advisory from 2 AM to 8 AM EDT Sunday for NHZ003-004. MARINE...None. && $$ SYNOPSIS... NEAR TERM...Cempa/Jensenius SHORT TERM...Jensenius LONG TERM...Hanes AVIATION...Hanes/Jensenius MARINE...Hanes/Jensenius is the U.S. government's official web portal to all federal, state and local government web resources and services.