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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KGYX 250038
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
738 PM EST Wed Feb 24 2021

.SYNOPSIS...
Low pressure will race eastward along the Maine-Quebec border
tonight bring accumulating snow to areas along the the border
and scattered rain showers elsewhere. A cold front will cross
the forecast area tonight with winds increasing later tonight
and gusting around 30 MPH on Thursday. Another fast-moving
weather system will move across the forecast area on Saturday
bring rain and snow. Colder high pressure then builds in early
next week.

&&

.NEAR TERM /TONIGHT/...
730PM UPDATE...
First wave of light precipitation is crossing the area
currently, although few observations so far have reported
anything at ground level. Surface low remains to the northwest
along the NY/Ontario border. Still expecting the most
significant precipitation to skirt the northern border of NH and
ME tonight where a few inches of snow is possible. Elsewhere
another round of light rain showers is possible this evening
before the cold front moves across tonight.

ORIGINAL DISCUSSION...
A short wave trough and attendant SFC low pressure center
located over Lake Huron as of this Wednesday afternoon will race
eastward along or near our border with Quebec tonight. As such,
much of the forcing for ascent will be north of our CWA.
However, locations near the Canadian Border such as Coburn Gore
northeastward to near Jackman should pick up at least a few
inches of snow tonight. South of that area, the rest of the
forecast area will largely be warm sectored overnight allowing
for mostly dry weather and relatively mild overnight
temperatures. The exception will be a fast-moving line of rain
showers (currently located from KPIT northeastward to eastern
Lake Ontario) that will affect the rest of the forecast area
this evening. If we had more moisture, there might be a few
thunderstorms. However, will leave them out of the forecast due
to lack of instability.

A cold front sweeps across the forecast area late tonight with
gusty winds. Temperatures south of the mountains will be pretty
warm overnight due to being warm sectored with a strong low
level jet in place. Most locations will remain in the upper 30s
to lower 40s unless localized decoupling takes place.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
Strong CAA will occur on Thursday in the wake of the cold
front. Temperatures will be 5 to 10 degrees colder than today,
with a decent wind chill. Westerly winds will gust around 30 MPH
for much of the day with some gusts around 35 MPH possible with
good mixing expected. We should remain short of wind advisory
criteria outside of some localized instances. Upslope snow in
the mountains in the morning will wane as the day progresses.

High pressure gradually builds in from the west Thursday night
with gradually diminishing winds and fair weather.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Overview: A series of short-waves will move through New England
beginning late Saturday through early to mid next week bringing
multiple chances for both rain and snow to northern New England.
Rain will be the predominant precipitation type in most
locations but the mountains will likely be just cold enough for
at least minor snow accumulations. A temperature roller coaster
is expected with daily high temperatures both above and below
average, although above average will be more frequent.

Impacts: Minimal. Some locally icy spots will be possible each
morning as daytime temperatures rise well above freezing allowing
for melting of snow and ice before refreezing at night. Rain and
snow late Saturday afternoon and night may result in locally slick
travel conditions, especially across the north.

High pressure will be centered to our south and west on Friday
morning before moving northeastward off the Southern New England
coast by Friday evening. This will result in a mostly sunny but cool
day with high temperatures ranging from the middle 20s across the
north to the 30s across southern NH and southwestern ME. A few
locations near the Massachusetts state line may approach the 40
degree mark. Despite northwest winds resulting in upslope flow
there will be enough subsidence over the area that even the
mountains should stay dry and mostly sunny.

Clouds will increase overnight on Friday and into Saturday
morning as high pressure moves well off to our east and an area
of low pressure associated with a frontal system advances
northeastward towards New England. WAA may result in a brief
period of light snow or flurries across the region during the
morning hours, especially across southwestern NH, as indicated
by the latest model guidance. As this weak system continues to
advance northward southerly winds at the surface will allow
temperatures to climb into the middle 30s across the north to
the middle 40s in southern NH. Initially, 850 mb temperatures
on Saturday morning and early afternoon will still be cold
enough to sill support a few wet snowflakes to reach the surface
even where surface temperatures are well above freezing but
during the evening warmer air aloft will result in a changeover
to all rain for most areas outside of the mountains. Some snow
accumulations will be possible across the mountains and far
north, but even in these areas rain may still mix in at times.
Model ensemble means are in good agreement with generally
bringing in between a quarter to locally a half inch of total
QPF, with the highest amounts likely closer to the coast. There
remains some disagreements in ensemble guidance in potential
snow accumulations as the GFS ensembles are generally warmer
than the ECMWF but on average expecting a coating to a half inch
of snow for the coastal plain and foothills before the
changeover to rain while the far north and mountains may receive
several inches of snow.

This system will rapidly move to the north and east of the area by
Sunday morning as high pressure builds to our west. Skies will be
partly cloudy with unseasonably warm high temperatures ranging
from near 40 across the north to the lower 50s across southern
NH. Another system may bring rain and snow on Monday as a
relatively weak disturbance drops south out of Canada. The CMC
ensembles are the most bullish on this potential as it develops
a secondary low along or just offshore, which enhances
precipitation chances. Due to this system still being several
days out and a lack in ensemble agreement chance PoPs were used
in this forecast package. Temperatures will still be mild though
into the 40s and therefore rain would be the favored
precipitation type. A cold front will then cross through New
England on Monday afternoon or night pushing this system out of
the area as much colder air filters in behind it. High pressure
will then move in for Tuesday and and Wednesday with
temperatures at or below average.

&&

.AVIATION /01Z THURSDAY THROUGH MONDAY/...
Short Term...VFR conditions with a few pockets of MVFR cigs are
expected tonight for most areas except in the mountains where
lower conditions are expected in snow or mixed precipitation.
LLWS will be present at most terminals tonight as a
southwesterly low level jet of up to 50 kt moves overhead. VFR
conditions are expected Thursday outside of the mountains.
Westerly wind gusts 25 to 30 kt are expected Thursday which
will diminish Thursday night.

Long Term...VFR conditions expected on Friday for all terminals
with west winds becoming southwesterly during the evening at between
10-15 kts. Patchy light snow on Saturday morning may result in
MVFR conditions for some, especially across southwestern
terminals. Widespread MVFR/IFR conditions possible Saturday
afternoon and night as rain and mountain snow overspreads the
region. VFR conditions will return by Sunday morning.

&&

.MARINE...
Short Term...Gales continue for the outer waters with small
crafts in the bays tonight and Thursday. Confidence in gales is
high. Winds and waves gradually subside Thursday night as high
pressure pushes eastward toward the region.

Long Term...Winds and seas should remain just below SCA
criteria on Friday with northwest winds gusting to around 20
kts, especially early. SCA conditions are likely beginning
Saturday afternoon through Saturday night as strong WAA allows
southerly winds to gust between 25-30 kts and seas build to 4-7
feet. Winds decrease on Sunday to less than 25 kts but seas will
remain elevated at 4-6 feet.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 7 PM EST Thursday for ANZ151-153.
     Gale Warning until 7 PM EST Thursday for ANZ150-152-154.

&&

$$

NEAR TERM UPDATE...Ekster
SHORT TERM...Ekster
LONG TERM...Tubbs
AVIATION...Ekster/Tubbs
MARINE...Ekster/Tubbs