Lebanon, Maine 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

449
FXUS61 KGYX 292040
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
340 PM EST Wed Jan 29 2025

.SYNOPSIS...
Cold high pressure will build in tonight through Thursday. Low
pressure will pass just to our south on Friday bringing with it
some light accumulating snow, and perhaps some light rain
across southernmost New Hampshire. Another cold high pressure
system moves in for Saturday. A warm front approaches Sunday.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Low pressure is beginning to move away from our area now and
this should bring an end to any snow showers or squalls by 7 pm.
Otherwise, A cold and brisk night with wind chills 20 below zero
or lower in the mountains where a cold weather advisory remains
in effect.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
High pressure crests over the region Thursday making for a sunny
but cold day. Increasing clouds Thursday night as low pressure
approaches from the southwest.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Friday morning, precipitation will be spreading north towards
northern New England. Precipitation should begin light and
patchy during the morning hours, picking up in coverage and
intensity into mid afternoon. Consensus trend has been to bring
greater QPF into the southern half of the CWA compared to the
forecast yesterday afternoon. This has resulted in increasing
PoPs through central NH and much of southern ME from the coast
to the foothills. With cold air in place at onset, mostly snow
is currently forecast north of a Concord to Portland line.

Precip types could become a bit more complex, as well as exact
onset time, however. Upper levels and surface should be
moistening quicker than the low levels, presenting a chance for
a period of virga prior to appreciable measurable precip. Should
this dry layer hold, start times could be closer to noon or
early afternoon, with just scattered precip during the morning
in southern to central NH. The precip type during the morning
could also be falling into a warm layer, resulting in melting,
before falling on prior cold pavement. Thus, a brief period
freezing rain Friday morning into early afternoon cant be ruled
out before surface temps warm. Will monitor forecast soundings
for evap cooling which may weaken this warm layer, keeping on
track with current forecast of a rain/snow event.

Cooler air should work on filtering back in as bulk of pressure
systems pass south of the CWA. This will trend precip types
back to snow for much of the area, with rain/snow mix in
southern NH. In general, lifting dynamics are broad but weaker,
leading to the bulk of QPF across NH and far southern ME, mainly
less than a half inch. This could lead to another light precip
event of 2 to 4 inches for central NH into the coast and
foothills of ME.

Area of low pressure pushes east Saturday, with a somewhat tight
pressure gradient and NW flow. Thus, expect Sat to be gusty,
advecting in cooler air from Quebec. This gradient does slacken
into the overnight period, and a period of good radiational
cooling is possible. NBM sky guidance does indicate the chance
for some cloud cover, and this could dampen the cooling ability.
But, if this turns out to be high cirrus, cold temps could still
be on for the night, with many locations potentially bottoming
out below zero.

Sticking with an active pattern, another area of low pressure
will quickly advance on the region behind this strong high
Sunday night into Monday. This time, the low track will be to
the north of central New England. On the leading edge of
mid/upper jetstream, this system has consistently been very
progressive, but drawing in Atlantic moisture amid return flow
from departing high. This fetch may be responsible for quite the
warmup, where highs Monday top out in the low to mid 40s.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
Short Term...VFR tonight after linger snow showers pass by 00z.
VFR Thursday except for some MVFR ceilings and snow showers
at HIE.

Long Term...MVFR ceilings arrive Friday, along with RA/SN. SN
seems more likely north of MHT/PSM/CON which could also bring
vis towards IFR criteria. Improvement is possible into Saturday
morning with precipitation tapering off, and VFR likely
overnight into Sunday. Another period of impactful weather is
possible Sunday night and Monday.

&&

.MARINE...
Short Term...Gale warnings have been hoisted in all areas with
the exception of SCAs in Casco Bay. Freezing Spray Advisories
have also been raised.

Long Term...Areas of low pressure pass south of the waters
Friday and Friday night. This will influence offshore flow and a
tight pressure gradient Saturday for gusty winds, mainly falling
within SCA criteria. These slacken as with wave heights
overnight into Sunday as strong high pres moves overhead.
Another system approaches Sunday night into Monday, inland and
north of ME/NH.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Cold Weather Advisory from 3 AM to 10 AM EST Thursday for
     MEZ007>009.
NH...Cold Weather Advisory from 3 AM to 10 AM EST Thursday for
     NHZ001-002.
     Wind Advisory until 9 PM EST this evening for NHZ011>015.
MARINE...Gale Warning until 11 AM EST Thursday for ANZ150-152-154.
     Freezing Spray Advisory until 11 AM EST Thursday for
     ANZ150>154.
     Small Craft Advisory until 6 PM EST Thursday for ANZ151-153.

&&

$$