Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 031714

Area Forecast Discussion
National Weather Service Gray ME
1214 PM EST Sat Dec 3 2016

Low pressure over eastern Canada will move east into the maritimes
by tonight. This system will provide scattered snow showers in
the mountains today. A ridge of high pressure will slowly build
into the region by Sunday, before moving offshore Sunday night. A
weak weather disturbance may bring a few snow showers to the
region Monday. Otherwise, cold high pressure will settle in for
the start of the week. A snow and rain mixture may enter the
region midweek.


1215 PM Update...With short wave trough moving through the mean NW
flow, enough forcing for ascent is present to allow for some light
spotty showers down to the coastal plain in ME. Have therefore
updated pops a bit. No big changes otherwise...just plenty of
clouds and gusts 25-30 MPH.

1010 AM Update...Just a few minor adjustments to the going
forecast based on latest trends in observational data. Upslope
snow showers in the mountains are expected to continue this
afternoon into this evening as cool cyclonic flow with embedded
sewd moving short waves continue. A few additional inches possible
in most west-nw facing terrain in NH and the far western ME
mountains. Otherwise, variable cloudiness and wind gusts around 25
mph expected downwind of the mountains to the coast for the rest
of the afternoon.


A cold cyclonic flow will dominate today with gusty northwest
winds with cold air advection and scattered orographic snow
showers in the mountains and higher terrain. An inch or two of
additional snow is possible in the areas where more favored
orogaphic lift gets enhanced on the northwest flow. Downsloping
areas will see some sun. Temps will be colder with highs off the
blended models which puts them into the lower 30s in the mountains
to lower 40s along the coast.


The northwest flow abates as the area of low pressure in the
maritimes continues to move east allowing high pressure to build
east from the Great Lakes region. Skies will become clear over
most areas except in the mountains where clouds will linger. Over
night lows will range from the upper teens in the mountains to
upper 20s to near 30 along the coast.

Sunday a surface and upper ridge axis will move across the area
producing sunny skies and lighter winds. The center of the cold
air mass will be over the area so high temps are only expected to
range from the mid 20s in the mounhtains to mid 30s elsewhere.


Surface high pressure will crest over the region Sunday night.
This will allow for clear skies and light winds which will lead to
radiational cooling.

The cold thermal profiles will allow for scattered light snow
showers or a period of light snow to develop as a weak and fast
moving trough approaches from the west. What little snowfall will
mainly be confined to western areas. Some of the snow will likely
sublimate as it falls through a dry layer in the lower levels of
the atmosphere.

High pressure will reestablish itself over New England on
Wednesday as low pressure passes by well south of the region,
bringing mainly just clouds to the region. By Thursday, a more
vigorous area of low pressure will move northeast from the Ohio
River Valley and into Southeast Canada. This will allow for a
moist southerly flow to develop on Thursday along the coast.
Further inland, an inversion may remain in place as strong warm
air advection occurs above the surface. A mixture of rain and snow
will change to snow showers by Friday as a strong cold front
sweeps through the region behind the departing and intensifying
area of low pressure moving through southern Canada. This will set
the stage for a prolonged period of below normal temperatures and
gusty west to southwest winds.


Short Term /through Sunday/...VFR conditions except MVFR at KHIE
into the afternoon. By early evening conditions at KHIE also
improve to VFR.

Long Term...VFR conditions expected Sunday through Monday
morning. Areas of MVFR/IFR ceilings Monday afternoon, mainly over
New Hampshire. VFR Monday night and Tuesday. IFR/LIFR
ceilings/vsbys developing on Wednesday.


Short Term /through Sunday/...SCA conditions expected into tonight
in the bays and through later toonight over the outer waters.
Strong cold advection combined with a rather strong Northwest
pressure gradient will cuase gusty conditions to approach 30 kts
at times. Tonight with colder air over the warmer waters some
enhanced gusts possible over the outer waters so extended the
times for those outlying areas.

Long Term...
Winds and seas will remain below SCA thresholds for several days.
However, southeasterly winds and seas will increase Thursday and
Thursday night. A wind shift to the west will occur Friday,
ushering colder air on Gale Force winds.


MARINE...Small Craft Advisory until 10 PM EST this evening for ANZ151-
     Small Craft Advisory until 4 AM EST Sunday for ANZ150-152-154.



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