Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 121037 AAA AFDGYX Area Forecast Discussion...UPDATED National Weather Service Gray ME 537 AM EST Thu Jan 12 2017 .SYNOPSIS... It will be another warm day across northern New England today, with periods of rain showers expected. A cold front will drop into the area from the northwest tonight and usher in colder air on gusty northwest winds on Friday. The cold weather will last through the weekend as high pressure builds across the area. Expect a gradual warm up next week as warm air pushes north into the area. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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540 AM Update... Warm advection showers are now moving through NH and Maine with temperatures gradually increasing each hour. Made minor changes to PoPs and updated temperatures to match current speed of warming. Some more robust convection is to the west and will be arriving in northern NH and the western Maine mountains shortly. Once again most of this is rain but there may a few pockets of freezing rain in the valleys which will diminish quickly as temperatures increase this morning. Previous discussion... Deep low pressure was moving through northern Canada this morning, dragging a cold front through the Great Lakes region and into the southern Plains states. The front will eventually reach New England late tonight. Before this occurs, warmer air ahead of the system will continue to nurture scattered warm advection showers throughout the day. Short wave energy in SW flow aloft is driving the periodic nature of the showers...and there will be a couple other batches of precipitation moving through today. Temperatures will be well above freezing, but rain and fog will nonetheless make for a dreary day overall. Temperatures across the region ranged from the upper 20s to lower 40s and have been rising overnight. Patchy black ice may be a concern on road surfaces that are below freezing for the next few hours, however that threat is diminishing. Readings will ultimately warm into the mid 40s to lower 50s due to the strong warm advection and SW winds.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... Rain over the higher terrain will mix with or change to snow tonight as temperatures begin to fall. Orographically lifted snow showers will be the only showers of note overnight. Temperatures will be on the warm side ahead of the cold front which moves through overnight. The cold air advection begins in earnest Friday... and this will have the effect of creating a small diurnal range between Friday morning`s lows and Friday`s highs... so that some locations may only warm a few degrees before readings begin to tumble during the day. NW winds will gust to near 40 mph making for a blustery and cold day even though skies will be sunny. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Winds begin to diminish Friday evening as high pressure builds into the area from the west. The high only just barely makes it toward western New Hampshire by sunrise, so expect winds to remain strong enough to prevent a strong inversion from setting up, keeping the low levels mixed. However, temperatures still drop pretty low on cold advection, with lows below zero to the northwest of the mountains and in the single digits to the southeast. The high crosses the area on Saturday with light winds and a clear sky expected. Temperatures only warm into the teens and 20s, so it will be a cold day. A broad area of high pressure remains over the area for the next several days, but it is briefly broken up by a shortwave trough which drives a second cold front toward the area Saturday night. The GFS hits this feature harder than the ECMWF, and there is very little moisture to work with on this, so in general expect this to be mostly unnoticed. It could cause an uptick in wind speeds Saturday night as well as bring some clouds to the mountains which could prevent an otherwise excellent radiational cooling night. However, even if these flies disrupt the ointment, there should still be several hours of good cooling Saturday evening. Based on the amount of dry air available Saturday evening before the dry front arrives, there is the potential for temperatures to drop below zero. Current forecast represents a compromise between the warm model low temperatures and the much colder temperatures that are possible. Secondary area of high pressure moves across the area Sunday into Sunday night behind the minor front. Expect temperatures a little closer to normal on Sunday, generally around freezing for a high. Sunday night should feature good radiational cooling, but there will not be quite as much dry air so lows will bottom out in the teens to near zero. Models continue to agree on the longwave pattern for the extended forecast which features a large trough over the southwestern United States which sends warm air northward into a developing ridge over the eastern United States next week. The consensus now favors some of the energy from the southwestern low ejecting across the center of the country on Tuesday, arriving in New England Tuesday night, bringing a chance of light rain or snow. The broader ridging remains through the middle to later part of the week which signals warm temperatures for New England. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... Short Term...VFR conditions dropping to MVFR early this morning and then to IFR ceilings and MVFR visibilities as periods of rain showers become more widespread and clouds thicken and descend. Cold front will move through tonight after 0Z clearing out some low level moisture and improving ceilings. Drizzle and fog may still linger through Friday morning. Gusty SSW winds today will become WNW overnight and increase with gusts to 35 kts on Friday. Long Term...High pressure crossing the area should provide light winds and VFR conditions through the weekend and into early next week. The only exception could be a period of MVFR ceilings north of the White Mountains Saturday night into Sunday morning, but this is still fairly uncertain. && .MARINE... Short Term...Small craft continues today ahead of a cold front and behind the cold frontal passage as well. A gale watch has been posted for mid morning Friday through late Friday as the pressure gradient increases markedly behind the front. Long Term...Winds diminish Friday evening into Saturday as high pressure moves in behind the front. A broad area of high pressure remains over the waters through early next week leading to a period of light winds and low wave heights. && .GYX WATCHES/WARNINGS/ADVISORIES...
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ME...None. NH...None. MARINE...Small Craft Advisory until 5 AM EST Friday for ANZ153. Gale Watch from Friday morning through Friday evening for ANZ150>152-154. Small Craft Advisory until 5 AM EST Friday for ANZ150>152-154.
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&& $$ NEAR TERM...Hanes SHORT TERM...Hanes LONG TERM...Kimble

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