Area Forecast Discussion
Issued by NWS Portland, ME

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715
FXUS61 KGYX 240023
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
723 PM EST Fri Feb 23 2018

.SYNOPSIS...
As low pressure moves through Quebec, it will send a warm front
through New England tonight. Expect some wintry precipitation as
this moves through. A cold front moves through on Saturday but
not before temperatures warm up into the 40s and 50s. The next
storm system will bring more widespread precipitation on Sunday,
with mainly snow or sleet being the dominant precipitation
type. There is also a chance for some freezing rain or rain depending
on the track. Fair weather returns for the first half of week
as a ridge of high pressure slowly builds over the region.
Another complex weather system affect the region Thursday and/or
Friday.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
700 PM Update...
Rain and mixed precipitation currently moving through the
forecast area with generally rain across southern New Hampshire
and coastal sections of Maine with a little sleet mixing in at
times. Farther inland precip in the form of sleet and freezing
rain and some isolated reports of snow. Back edge of
precipitation is racing eastward into western New England and
should be ending in western zones between 800 and 900 PM and
between 900 and 1000 PM in eastern zones. Amounts are on the
light side with accumulations of around a tenth of an inch so
far. Road departments are reporting slick travel in spots and
roads are being treated. Will likely be dropping Winter weather
advisories when they expire at 1000 PM.


Prev Disc...
Low pressure tracking through Quebec sends a warm front across
our area this evening. Expect warm advection style precipitation
along and ahead of this feature with precipitation likely
starting as snow or rain depending on low level temperatures. As
the evening goes on, temperatures will warm aloft and may change
things to freezing rain in areas that get below freezing at
ground level. As a result, will keep the Winter Weather Advisory
in effect. Do not expect substantial icing amounts, but it could
be enough to make things slick.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Although winds will be westerly behind the front on Saturday
morning, the cold advection does not drop in from the north
until later in the day. As a result, expect warm temperatures in
the morning with good low level mixing. Generally 40s and low
50s. This should change Saturday afternoon and evening as colder
air pours in from the north.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
The southerly flow ahead of a large area of low pressure moving
northeast over the western Great Lakes will spread moisture into the
region during the day Sunday.  At the same time, high pressure over
the Canadian Maritimes will funnel cold air into the region near the
the ground.  Precipitation will spread northeastward from
southwestern New Hampshire, starting about daybreak, reaching
all of western Maine by about noon. The forecast challenge
continues to be precipitation type. The precipitation is
expected to start as snow in all areas. However, as a wedge of
slightly warmer air moves over the region at about 7000 feet
aloft, the snow may mix with or change to sleet and possibly
freezing rain. Below this warm wedge in the atmosphere,
initially, there will be sufficient sub-freezing air to
refreeze any melted or partially melted precipitation. However
with time, the entire column of air will gradually warm to allow
for a brief period freezing rain or rain. The other part of the
challenge will be surface temperatures. The cold and dry flow
from the high pressure center to the northeast will help
suppress warming during the day, contributing to the possibility
of freezing rain if temperatures aloft warm sufficiently to
melt the falling snow or sleet before surface temperatures warm
above freezing.


At this time, models suggest that most of the precipitation
across the region will fall as snow and/or sleet with the GFS
leaning more toward snow with the NAM slightly warmer aloft
leaning more toward sleet. Across southern sections of the
area, the precipitation may briefly change to rain or freezing
rain before ending late Sunday afternoon or evening. Farther
north, the snow may mix with a brief period of sleet or freezing
rain before ending. High temperatures Sunday are likely to be
within a few degrees of freezing all areas, warming a few
degrees as the precipitation comes to an end. Total snowfall
amounts will likely be 1 to 3 inches along the coast, to 3 to 6
inches across the interior and foothills. The northern mountains
may see somewhat less snow as overall precipitation amounts are
lower.

Skies should clear Sunday night with temperatures only cooling
to the mid 20s north to near 30 south. A ridge of high pressure
build across the area Monday leading to a mostly sunny day with
rather mild temperatures mainly in the 40s across the region.
The ridge should lead to dry weather for Tuesday and Wednesday,
except in the mountains where snow showers are possible.

Another weather system may affect the region Thursday or Friday
with the possibility of rain and/or snow. Models are not
consistent on the track of this storm with the European model
keeping this system well out to sea.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
Short Term...Expect MVFR to IFR conditions with light
precipitation this afternoon and evening for most areas, with
improving conditions by morning.

Long Term...IFR to LIFR conditions Sunday in a mix of
snow, sleet, rain and possibly freezing rain. VFR conditions
expected Monday through Wednesday.

&&

.MARINE...
Short Term...Southerly winds today shift to west tonight and the
northwest on Saturday. Could see some gusts to 25 KT during this
time period so will keep the Small Craft Advisory in place,
although will expand it to Penobscot Bay and lengthen its
duration over the outer waters.

Long Term...SCAs likely Sunday and Monday, then winds and seas
expected to be below SCA criteria Tuesday and Wednesday.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Winter Weather Advisory until 10 PM EST this evening for
     MEZ007>009-012>014-018>022-025>028.
NH...Winter Weather Advisory until 10 PM EST this evening for
     NHZ001>006-009.
MARINE...Small Craft Advisory until noon EST Saturday for ANZ150-152-
     154.
     Small Craft Advisory until 5 AM EST Saturday for ANZ151.

&&

$$



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