Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 300032 AAC AFDGYX Area Forecast Discussion...UPDATED National Weather Service Gray ME 732 PM EST Tue Nov 29 2016 .SYNOPSIS... Low pressure developing over the Gulf of Maine will bring rain and a wintry mix of precipitation to the region this evening before moving off to our east after midnight. A very brief lull in the precipitation is expected Wednesday morning before another low pressure system spreads rain back into the region Wednesday afternoon...with a changeover to snow possible over far northwestern Maine Wednesday night. Somewhat drier air will arrive on Thursday and Friday with temperatures cooling as we move into the weekend. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
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729PM Update: PoPs/Precip type generally looking good. Adjusted temperatures down inland and up along the immediate coast based on evening observations. Have also matched current wind trends...with upward adjustments over the marine waters /see 47 kt peak wind at IOSN3/. Back edge of heavier precipitation marching east...and may be able to clear some of the advisory area before the night is through. 543PM Update: Have made a few adjustments to continue to trim winter weather advisory based on latest mesonet observations and correlation coefficient values from the GYX 88D showing a deepening llevel warm layer and surface temperatures slowly edging above freezing. Have extended advisory for a few more hours for Oxford/Franklin/Somerset counties based on multiple reports of temperatures around 30F as webcams have shown some /albeit not much/ snow...and a transition to freezing rain here. Temperatures/precip timing continue to be on track with little changes here. Previous Discussion below: Winter weather advisories have been dropped for all but the northernmost counties in western Maine. Cold air wedge remains entrenched over the capital area and the foothills as well and is taking its time to erode as warmer air arrives from the SW. Areas still in the advisory will continue to see a mix of snow and freezing rain...gradually changing over to rain as the night wears on. Elsewhere expect rain, heavy at times, and dense fog. Precipitation chances ramp up this evening to near 100% as a coastal low pressure system closes off near Portsmouth and tracks along the New England coast towards the Canadian maritimes. Franklin and Somerset Counties may see temperatures at all levels staying cold enough for snow through tonight, allowing for accumulations 3 to 6 inches. Overnight lows will be tricky and depend on how far the warm air can mix down and impinge northward. In general lows will be within a few degrees of 3 pm temperatures...or in the lower 30s to lower 40s.
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&& .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... After a break in the precipitation for most areas overnight and into early tomorrow morning, another short wave and associated warm front begin to move in from the west. Precipitation will be rain for almost all areas but there could be a few cold mountain valleys that may see snow mixing in and light accumulations. Temperatures will be in the 40s across the region with mid 30s towards Jackman. It will be another foggy and dreary day and night. By the end of these 2 events much of northern New England will receive between 1 and 2 inches of rain. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Both ensemble and deterministic solutions are now in decent agreement on the longwave pattern through early next week. Temperatures through at least Sunday will average above normal as mean jet stream position keeps the really cold air bottled up to our north and west. We begin the period with an upper low centered over the Great Lakes. The associated surface low will be over western Quebec with an occluded front extending southeast into the region with a triple-point low over the Maine coastal waters. This frontal system and coastal low will race northeast in response to associated shortwave impulse exiting into New Brunswick. The upper low will gradually open up as it slides into New Brunswick by Friday with a broad lingering trough across the Great Lakes and New England through Saturday. by Sunday...rising heights as ridge approaches New England. In the dailies...occluding frontal system pushes into northern New England with models agreeing on developing triple point low over the Maine coastal waters. This surface development will draw colder air into the higher terrain which will help precipitation end as snow there on Thursday. Behind this departing disturbance...a broad trough with a series of embedded shortwaves that will traverse the forecast area through Saturday. This will result in considerable clouds for the higher terrain with upslope snow showers. Elsewhere...varying amounts of clouds with passing shortwave impulses as well as a low pop for rain/snow showers with p-type boundary layer temperature dependent. By Sunday...model blend offers ridging and a brief respite through Monday before the next disturbance approaches the region late Tuesday. It should be noted that over the past 12 hours the extended model solutions...both ensemble and deterministic... have come into much better agreement regarding early next week...lending increasing confidence in sensible weather details for that period. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... Short Term /through Wednesday Night/... Summary: Low pressure strengthening over the Gulf of Maine will continue the rainy conditions through the first half of tonight before gradual improvement arrives after midnight. After a brief respite Wednesday morning...rain will arrive from another low pressure system Wednesday afternoon...renewing the poor flying conditions that will continue through Wednesday night. Restrictions: Widespread LIFR/IFR conditions in rain...low clouds...and fog overnight will improve to MVFR/VFR Wednesday morning before deteriorating back to IFR/LIFR late Wednesday and Wednesday night in rain and fog. Winds: Light northerly winds inland and southeasterly winds 10g18kts at the coast will become light northwesterly everywhere by early Wednesday before shifting northeasterly 5-10kts Wednesday afternoon and evening...before shifting northwesterly towards daybreak Thursday. LLWS: Southerly winds 30-40kts at 2kft will continue at most sites for the next 2-3 hours before diminishing. LONG TERM... Thu...Widespread IFR in RA and mtn ra/SN...improving to mvfr in mtn shsn and VFR elsewhere. Fri - SAT...Areas of MVFR in mtn shsn. && .MARINE... Short Term...Southeast winds ahead of the developing low tracking near the coastline will strengthen and likely gust to gale force over the outer waters this evening into tonight. Winds should diminish a bit after the low moves by, but waves may stay up a few more hours. Long Term... Thu - Fri AM...Small Craft conditions are possible. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...Winter Weather Advisory until 11 PM EST this evening for MEZ007-012>014. Winter Weather Advisory until 1 AM EST Wednesday for MEZ008- 009. NH...None. MARINE...Small Craft Advisory until 4 AM EST Wednesday for ANZ151-153. Gale Warning until 1 AM EST Wednesday for ANZ150-152-154. && $$ SYNOPSIS... NEAR TERM...Arnott/Hanes SHORT TERM...Hanes LONG TERM...Schwibs AVIATION...Arnott MARINE...

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