Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 180307
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1007 PM EST Fri Nov 17 2017

.SYNOPSIS...
Northwesterly winds will diminish this evening as high pressure
continues to build in form the west. The high will crest across
the area early Saturday before gradually sliding offshore. A warm
front will lift northward on Saturday night with a mix of rain
showers south and rain/snow in the north. A cold front will
cross the region on Sunday bringing gusty winds and accumulating
upslope snows to the mountains. High pressure builds in for the
start of next week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Update...
Have updated the grids based on current conditions and latest
set of mesoscale models. Upslope clouds that were hanging in
tough over the western mountains of Maine and northermost New
Hampshire earlier this evening will continue to slowly dissipate
with time. Elsewhere, clear skies will continue with downslope
conditions. Winds have decoupled in many areas except for the
high terrain and in the Concord area of New Hampshire.

Have made minor adjustments to the overnight lows and dew points
based on current trends.

Prev Disc...
At 19z...a 985 millibar low was over the Canadian
maritimes while a 1024 millibar ridge was draped across the
eastern Great Lakes. The pressure gradient between these two
features will continue to relax over the next few hours with
northwest winds gusty northwest winds diminishing. With the
exception of some lingering upslope clouds across the mountains
this evening...a clear and cold night is on the way with lows in
the teens and lower 20s.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
On Saturday...the high pressure ridge will crest across the
forecast area during the morning before quickly retreating
offshore by afternoon. A milder return southerly flow will
develop by afternoon along with warm air advection clouds
arriving from the west ahead of the next progressive shortwave
impulse and associated low pressure system. Highs on Saturday
will average a good five to seven degrees milder compared to
today. Any precipitation that arrives will hold off until nearly
dusk and be confined to northern and western sections...with any
light wintry mix limited to areas near the international
border. Saturday night...an intensifying surface low tracks
just north of the eastern Great Lakes across Ontario province.
That will push a warm front north across the area with any light
mixed wintry precipitation across the mountains and
international border area changing to plain rain. Expect any
icing or wet snow/sleet accumulations to be quite light before
the transition to all rain occurs and temperatures continue to
rise overnight.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Sunday morning begins with low pressure moving along the Saint
Lawrence river to our north. As it moves north and east, it will
drag a rather robust cold front through the region. Strong
southerly flow ahead of the front will allow temperatures Sunday
morning to start off in the 40s to lower 50s. Right now it looks
like the front should swing through during the late morning and
early afternoon hours. Strong cold air advection sets up just
behind the front. Temperatures will begin to fall sharply during
the afternoon and evening hours. Expect winds of around 35kts to
mix down to the surface at most locations. While this should be
shy of high wind warning criteria, it may be enough to meet wind
advisory criteria. Will hold off on headlines for now and let
later shifts get a better look at things. The front moves
quickly offshore and by Monday morning high pressure will
dominate the eastern United States. Temperatures on Monday will
be around 10 degrees cooler than normal. High pressure remains
in place until Wednesday when another cold front is expected to
move through. This one looks much weaker though and it almost
completely washes out before passing through. It will likely
only consist of a small drop in temperatures and a wind shift.
High pressure remains in place through the end of the period.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Short Term /through Saturday Night/...becoming VFR throughout
this evening with gusty NW winds diminishing to under 10 KT this
evening. VFR through Sat...with MVFR cigs developing Sat evening
and lowering to IFR in RA and FG with areas of -fzra/sleet/snow
possible across the mountains.

Long Term...Expect mainly VFR throughout the period. There could
be a short time of IFR/MVFR vsbys and cigs Sunday morning ahead
of the cold front. However, once the front moves through VFR
conditions will return quickly. Strong gusty winds behind the
front could pose some LLWS concerns Sunday afternoon and
evening.

&&

.MARINE...
Short Term /through Saturday Night/...SCAs will remain in place
for the outer waters overnight. Gales have been dropped.

Long Term...Cold front moving through on Sunday will produce
strong gusty winds Sunday afternoon and evening. Winds will
certainly be strong enough to meet Small Craft Advisory criteria
and may approach Gale force.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 5 AM EST Saturday for ANZ150-152-
     154.

&&

$$
Cannon



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