Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 180751

Area Forecast Discussion
National Weather Service Gray ME
251 AM EST Mon Dec 18 2017

A weak warm front will lift north into the region today and will
stall over the region 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.


Weak 500MB wave will bring widespread light snow to the region
today. Warm air advection is increasing from the SW this
morning, with radar echoes just beginning to reach southern NH
this morning. This trend will continue throughout the day with
amounts from a tenth of an inch of snow to closer to 1.5" for
the Mid Coast. This will impact the morning and possibly the
afternoon commutes making travel slippery. Temperatures today
will remain chilly with highs ranging from the upper teens to
lower 30s.


On the backside of this system, light and spotty freezing drizzle
might be possible briefly early Tuesday morning. However, do
not have enough confidence in this scenario at this time to
issue an advisory. Tonight`s temperatures range from mid teens
north to upper 20s south and west. Tuesday we will see
increasing SW winds ahead of a cold front. This will bring
temperatures up into the 30s and 40s areawide. Winds will be
gusty with PoPs increasing across the mountains and foothills
quickly. This would deliver a couple inches of snow to the
region through Tuesday evening at least.


Cold front will shift offshore Tuesday evening. Expect any snow
showers downwind of the mountains to gradually end with skies
clearing before midnight. In the north...increasing upslope
flow and and low level moisture will keep snows showers going
through most of the night as a weak surface trough drops south.
Lows overnight will range through the 20s.

High pressure will slowly build in from the west Wednesday
through Thursday. Morning clouds and snow showers in northern
zones will gradually give way to sunny breaks in the afternoon.
Expect a mix of clouds and sun in the morning in southern zones
with clearing skies toward evening. High on Wednesday will
range from the mid 20s north to the mid 30s south. High
pressure will continue to build in from the west Wednesday
night and Thursday. Looking for mostly clear skies Wednesday
night and mostly sunny skies on Thursday. Lows Wednesday night
will range through the single numbers north and teens south.
Highs on Thursday will range through the teens north and 20s

Looking for increasing high clouds Thursday night as a warm
front lifts north to the west of the forecast area. Lows
overnight will once again range through the single numbers
north and teens south.

Broad area of over-running ahead of low pressure moving
through the Great Lakes will bring thickening clouds and
occasional light snow to the region on Friday. Highs will
range through the 20s north and 30s south.

Warm front will lift north through the region Friday night
with snow changing to a mix and eventually going over to rain
overnight as strong low level jet pushes warm air northward.
Some differences between models in how fast cold air gets
scoured out in northern zones where mixed precip could hang
on for much of the night.

Cold front will press in from the west on Saturday with rain
persisting into early afternoon before the cold front pushes
offshore. Looking for clearing from east to west during the
mid and late afternoon. Expect highs to top out in the morning
before falling back behind the front in the afternoon.


Short Term...All terminals will decrease in snow
today....probably yo MVFR/LIFR until this afternoon/ The
exception is the mountains where HIE and LEB could see longer
amounts of precipitation. Winds increase quite a bit behind the
outgoing cold front Tuesday.

Long Term...VFR Tuesday night through Wednesday with areas of
MVFR/IFR ceilings/vsby in the mountains Tuesday night and early
Wednesday. VFR wednesday night through Thursday night. IFR//LIFR
ceilings developing Friday.


Short Term...Gales begin Tuesday afternoon for all zones in
strong cold air advection. We have issued a watch for this

Long Term...Gales likely Tuesday night through Wednesday.


MARINE...Gale Watch from Tuesday afternoon through Wednesday evening
     for ANZ150>154.



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