Area Forecast Discussion
Issued by NWS Portland, ME

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897
FXUS61 KGYX 180416
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1116 PM EST Fri Feb 17 2017

.SYNOPSIS...
A warm front lifts into the northeast tonight followed by a
cold front on Saturday afternoon. A secondary cold front will
slowly approach from the north Sunday and will drop south
through the region Sunday night. High pressure will build in
from the west on Monday and will crest over the area on Tuesday.
High pressure will shift offshore Tuesday night as a warm front
pushes in from the west. The warm front will push east of the
region on Wednesday.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
11pm update...
Quick update to drop expired headlines for SCA"s on the coastal
waters. Just looking for variable high clouds associated with
weak over-running approaching from the west overnight as surface
high pressure crests over the region. Aside from a few temp
tweaks...no other changes planned attm.


Previous discussion...
945PM UPDATE...
Temperature drops in a few locations have been impressive the
last hour. Whitefield dropped 9 degrees in 1 hour and Lebanon
dropped 8 degrees. These drops have been spotty, as is typical
on radiational cooling nights. Expect the general floor for
temperatures to be somewhere around 10 degrees except in valley
locations or areas with fresh snow pack which could drop closer
to zero. Have made one more crack at overnight lows based on a
combination of known cold spots and current observed trends, but
this sort of variability in nighttime temperatures is impossible
to really capture even in the gridded forecast.

745PM UPDATE...
It`s a nearly cloudless sky out there this evening aside from
some brief blow-off clouds downwind of the White Mountains.
Winds are diminishing which will allow temperatures to drop
quickly the next few hours. Some high level cirrus are moving
through upstate New York and will begin arriving in New
Hampshire around midnight and spread across the area overnight.
This will limit overall cooling potential, but until then expect
a free fall.

445PM UPDATE...
Afternoon dewpoints have dropped considerably with good mixing
conditions. Have updated the forecast primarily to adjust these
values based on current observed trends. Have also made a few
minor tweaks to overnight lows as high pressure moves overhead
tonight providing good radiational cooling conditions. Could see
some cloud cover moving in late which could limit overall
cooling potential, though.

ORIGINAL DISCUSSION...
It`s been quite a while since much of the region has seen the
sun but at 3pm skies were clear across northern New England. The
departing low pressure provides for a gusty northwesterly wind
with gusts to 20-25mph. High pressure will build in from the
west this evening and winds will decrease soon after sunset.
With the clear skies some colder pockets will develop. A very
weak disturbance passing through late in the overnight into
tomorrow morning will increase clouds for the mountains and keep
temperatures from dropping below zero.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
High pressure will remain in control for Saturday keeping skies
mostly clear. Only exception will be the northern mountains
where continued upslope flow may managed to eek out a few
flurries. Warm air aloft will allow temperatures to climb into
the mid 40s south to upper 30s north.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
This coming week looks like a welcome period of rest from
snowfall for New England outside of a few scattered orographic
showers. Temperatures will also be above normal most days
with readings in the 40s forecast for highs several times this
week.

A cold front will be pushing south through the region on Sunday
before moving offshore and becoming less defined. Upslope snow
showers will bring some light accumulations to NH and the
western ME mountains during this time with some areas changing
over to rain during the day. Temperatures ahead of the front
will surge into the 40s for much of the area on westerly winds.

Gusty NW flow follows for Monday with high pressure centered
well to the north influencing the weather. Moisture is scarce
Monday and early Tuesday and morning lows will reflect colder
temperatures with single digits north to teens south Tuesday
morning.

High pressure moves into the Gulf of Maine and dives south as a
weak disturbance aloft attempts to drag a cold front east.
Depending on the timing we may see a mix of rain and snow with
this system Wednesday and Thursday...but QPF amounts will be
light in any case. High pressure returns for Friday.

Isentropic lift and moisture increase Friday night into Saturday
with a more significant precipitation event which again looks
like a mix of rain and snow given the warm temperatures that
will be in place.

&&

.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
Short Term...VFR conditions are expected through Saturday. Wind
gusts will rapidly diminishing this evening.

Long Term...VFR Sunday with areas of MVFR ceilings in the
mountains in the afternoon in -SHSN. VFR Monday and Tuesday.

&&

.MARINE...
Short Term...SCA`s remain up on the ocean waters however have
dropped the bays with this update. Expect winds to diminish
overnight and expect below SCA by midnight. SCA conditions may
once again develop later Saturday afternoon.

Long Term...Sunday night into Monday night winds will increase
in response to a cold frontal passage to near 25 kts and may
require a SCA for the waters.

&&

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

&&

$$



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