Area Forecast Discussion
Issued by NWS Portland, ME

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549
FXUS61 KGYX 142241
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
541 PM EST Thu Dec 14 2017

.SYNOPSIS...
High pressure builds in from the south overnight, and shift east
on Friday. Weak low pressure to our north and south will provide
clouds, and maybe a few snow showers or flurries Friday night
into early Saturday. High pressure builds in on Sunday and
starts a warming trend. Although slightly warmer, several fast
moving systems could provide some light precipitation early to
mid nest week.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
540 PM Update...Little change to the going forecast. Very cold
weather continues to be expected overnight with little in the
way of cloud cover. A few areas will decouple overnight
resulting in lows below zero in spots - especially with
snowcover now in place.

Previously...

High pressure will build in from the south later tonight, but
should see the breezy conditions continue through at least
sunset, with mainly clear skies overnight. Main question will be
if and how quickly sfc areas can decouple later after the winds
diminish. Looks like some radiational cooling will be possible
during the latter part at most locations, and forecast lows
currently reflect that, dropping into the single digits below
zero in the mountains, and the single digits above zero
elsewhere. Even with some lingering winds air aloft is still
plenty cold.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Friday should start off sunny, and generally remain on the
sunny side through most of the day before clouds start to move
in from the SW. With the sfc ridge moving slowly east sfc flow
will be light, and despite a bit of SW flow aloft, the lack of
mixing will keep highs on the colder side, and similar to
Thursday, generally in the teens N, to the low to mid 20s in the
S.

Weakening sfc low moving east along the St. Lawrence valley
will transition energy to developing coastal low well offshore.
This will spread clouds across the region overnight Friday.
Scattered SHSN can be expected in the north, and there is the
potential for some sct SHSN to the SE as the coastal low
develops as well, but overall any snow will be light with a
dusting at best. Lows will range from 5-10 above in the mtns, to
15-20 on the coast.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Backside trough crosses the area on Saturday and could trigger
some light mountain snows. It will be warmer, but still cold,
with highs in the 20s and low 30s. High pressure builds in from
the northwest Saturday night and Sunday with slightly colder
weather.

Cut off upper low ejecting out of northwest Mexico will track
northeast across the country this weekend, getting squashed by a
ridge in the southeast US as it does so. By the time its
remnants get into our area on Monday there may only be some
clouds left with it, but there will still be a chance of light
snow. Any accumulation will be light as there is not a good
moisture connection with it.

Broader upper trough arrives on Tuesday with another chance of
precipitation as it moves through. This one has a better
moisture connection and may pull in some warm air ahead of it.
Thus it may actually be warm enough for rain for much of the
area, but expect a return to colder conditions behind the cold
front which moves through Tuesday night.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
Short Term...Mainly VFR through Fri night.

Long Term...Should see some MVFR ceilings northwest of the
mountains with some light snow on Saturday but VFR elsewhere.
VFR areawide by Sunday. Could see MVFR and light snow area wide
on Monday but confidence is low and accumulations will be light.

&&

.MARINE...
Short Term...Surge of west winds behind a cold front is occuring
late this afternoon, and will likely continue into evening at
least, so SCA will hold as for now. May see winds drop off in
the bays by midnight or so. May need SCA again late Fri night.

Long Term...May see advisory level wind gusts late Saturday and
Saturday night behind a cold front. High pressure over the area
keeps conditions quiet through Monday.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 7 AM EST Friday for ANZ150>154.

&&

$$

NEAR TERM UPDATE...Ekster



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