Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 182249
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
549 PM EST Mon Dec 18 2017

.SYNOPSIS...
A weak warm front will lift north into the region this evening
and will stall over the region later tonight. A cold front will
approach from the west on Tuesday and will cross the region
Tuesday evening. High pressure will gradually build in from the
west Wednesday through Thursday and will crest over the region
early Friday. A warm front will approach from the southwest
Friday and will be followed by a cold front on Saturday. High
pressure will briefly build over northern New England on Sunday,
followed by low pressure moving up the east coast on Monday.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
545 PM Update...Have updated the forecast mainly for minor
changes to PoP, wx, snow, and temperatures based on latest
observational and spotter data. Snow continues, with the
heaviest on the coastal plain. Reports received so far are
anywhere between a half inch a 2 inches. Across southern NH not
much is falling at this time and not much is expected for the
rest of the night. Additional accums of an inch or two can be
expected mainly on the coastal plain in Maine with a little more
than that possible on the mid coast where an advisory remains in
effect. A little patchy drizzle will be possible on the coastal
plain as well a little later this evening, including
southeastern NH. A special weather statement remains in effect.

Previously...

Light snow is ongoing across much of the region. Multiple
reports indicate a very fluffy snow with low water content, so
have increased snow amounts but kept the QPF about the same.
Expect snow to increase along the coast as the warm front lifts
northward and low pressure strengthens slightly over the Gulf of
Maine. precipitation will come to an end from south to north
after midnight. As it does expect the upper layers to dry out
first setting us up for some freezing drizzle along the coast
this evening. With slightly warmer temperatures and less chance
for any accumulation before precipitation ends have opted to
just issue an SPS for southeast NH and extreme SW Maine
highlighting the potential travel impacts. Further east along
Penobscot bay snow will continue longer and with the fluff
factor is expected to result in several inches before a
transition over to freezing drizzle in the early part of the
night, and a winter weather advisory has been issued for this
area.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Tuesday a cold front will push into the region. Upslope snow
showers will develop bringing another few inches of
accumulation to the mountains along the Canadian border. Cold
air will continue to move into the region during the day with
temperatures dropping through the day. Blustery northwest winds
will add to the chill.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
A very gusty westerly flow will continue through Wednesday as
low pressure intensifies over the Canadian Maritimes. Some
upslope snow showers will accompany the strong flow over the
northern higher terrain.

Canadian high pressure builds over the region Thursday with
chilly conditions continuing. By Friday, low pressure will move
up the Ohio River Valley. A strong warm air advection pattern
ahead of the system will allow for snow to break out across the
region from south to north during the day. By Friday night,
continued warm air advection on a strong southerly jet will
allow for a non-diurnal temperature curve. Used the BTV top,
down weather tool to account for mixed precipitation during the
night.

By Saturday, most of the deep moisture and dynamics will be
north of our region. However, some light rain will continue with
thermal profiles possibly supporting a mix in the far north.

High pressure will briefly build into the region Sunday. Models
then diverge somewhat as to the exact timing and track of the
next low moving up the east coast later Sunday night into
Monday. This will likely bring more mixed precipitation to the
region.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
Short Term... Widespread snow showers are alternating between
MVFR and IFR conditions. This will continue through the evening.
In the interior expect a return to VFR after midnight for all
but the upslope region of the mountains where MVFR snow showers
will continue through Tuesday.

Long Term...VFR conditions Wednesday with areas of MVFR/IFR
ceilings/vsby in the mountains. VFR conditions continue Wednesday
night through Thursday night. IFR/LIFR ceilings developing
Friday into Saturday with VFR conditions Sunday.

&&

.MARINE...
Short Term... A warm front will lift north of the region
overnight tonight through early Tuesday morning. A cold front
will cross the waters late Tuesday. Behind the front winds will
increase to Gale force from Tuesday into Tuesday night.

Long Term...Gale force gusts are possible early Wednesday,
however confidence is not high enough at this time to extended
the warning through the day. A gale force southerly flow is
possible by early this weekend, followed by a return gusty
western flow by Sunday.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Winter Weather Advisory until 7 AM EST Tuesday for MEZ022-
     026>028.
NH...None.
MARINE...Small Craft Advisory from 4 PM Tuesday to 7 AM EST Wednesday
     for ANZ151-153.
     Gale Warning from 4 PM Tuesday to 7 AM EST Wednesday for
     ANZ150-152-154.

&&

$$

NEAR TERM UPDATE...Ekster


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