Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 071349 AAA
AFDGYX

Area Forecast Discussion...UPDATED
National Weather Service Gray ME
849 AM EST Wed Dec 7 2016

.SYNOPSIS...
A weak trough will move across the region today. This will spread
light snow into southern areas of the area around the morning
rush hour, but accumulations are expected to be very light. A slow
moving upper level low pressure system will move through southern
Canada Thursday and Friday, spreading some snow showers into the
mountains. This will also drive an arctic cold front through the
area later on Friday bringing much colder temperatures for the
weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Update...WAA is forecast to continue weakening over the area thru
early afternoon. This is allowing snowfall to slowly taper off
over Wrn ME. I do not expect accumulations to reach the 1 to 2
inches seen over parts of NH this morning...but could still result
in some slick roads. Behind this initial lift we remain in
cool...cyclonic flow so clouds and flurries should linger into the
afternoon.

Previous Discussion:
A weak short wave trough in advance of a broad upper Great Lakes
trough will move through the upper ridge axis exiting to the east
today. As it does so, the trough will get dampened out but will
still have enough lift to produce a band of light snow or snow
showers to move across the area with snow totals of less than an
inch accumulation expected. A very dry air mass is in place at
this time so the light snow will only manage to reach NH and
extreme southwest Maine for the morning commute. During the mid-
late morning the snow should reach all other areas north and east.
By later in the day the periods of light snow or flurries will
come to end over southern areas and then places north and east by
evening. There could be a mix or changeover to rain showers
briefly over southern areas and along coastal areas before the
precipitation ends in the afternoon as some boundary layer temps
warm and approach 40 degrees.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
Tonight and Thursday very little in the way of any clearing
expected as the broad upper trough over the Great Lakes moves
eastward into New England. This cyclonic flow will keep clouds
across the area. In the mountains scattered snow showers can be
expected. Stayed close to blended model guidance for temps.
Overnight cloud cover will keep temps from falling so lows will be
in the 20s. Thursdays high temps should be in the 30s to near 40.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Not much change from the previous thinking on the long term as
latest deterministic and ensemble model guidance looks largely
unchanged as a whole. The bottom line remains below normal cold
and the chance of a winter weather event Sunday night and Monday.

Cold air will be ushered in Thursday night in the wake of a short
wave trough and attendant cold front. Cold northwest flow then
continues through Saturday night with upslope snow showers in the
mountains through Friday. Both Friday night and Saturday night
will likely feature widespread lows in the teens and single
numbers. Saturday night should be the coldest night with SFC high
pressure cresting overhead. Low temperatures may have to be
adjusted downward a bit at the good radiators if thick cirrus
associated with an approaching short wave trough doesn`t move in
too early.

The next chance of appreciable snowfall continues to be centered
around Sunday night as a couple of short wave troughs traverse the
region. The 00z deterministic runs haven`t changed too much from
previous runs so therefore the general initial idea remains the
same...ie...a snow event for most with possible mix far
south...starting Sunday afternoon or night and lasting into
Monday. There are a few short wave troughs that are involved here
and still need to be better resolved moving forward - so forecasts
may change a bit over the next few days. At this time will
continue with a mostly snow forecast.

Thereafter it looks possible that another cold shot arrives by
midweek.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
Short Term...Mostly MVFR conditions expected today with light snow
or flurries as the weak trough moves through the area. Tonight and
Thursday generally VFR condition expected except in the mountains
where scattered snow showers will persist.

Long Term...Mainly VFR conditions expected Thursday night through
Sunday. The exception will be in the mountains where lower
conditions are expected Thursday night through Friday in snow
showers.

&&

.MARINE...
Short Term...Winds and seas to remain below SCA criteria through
Thursday.

Long Term...Northwest winds to small craft advisory levels are
expected Thursday night through Saturday night.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.

&&

$$

NEAR TERM...Legro



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