Lebanon, Maine 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

012
FXUS61 KGYX 301038
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
538 AM EST Thu Jan 30 2025

.SYNOPSIS...
Cold high pressure will build into the region today. 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 this weekend. A warm front approaches Monday with
high pressure building into the Northeast Tuesday and Wednesday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1035Z Update...
Just minor modifications to the near term portion of the
forecast this morning. The radar signature for snow showers in
the mountains has dissipated somewhat, however will continue
with chance pops for snow showers for a few more hours based on
latest webcams in the north.

Have update and highlighted southern New Hampshire in the HWO
for Friday`s system. This is where the greatest QPF is located.
If the models trend any colder, this is where some of the higher
snow totals may occur if the precipitation trends towards mostly
snow. The evening commute with be slick.

Prev Disc...
A frigid start to the day can be expected across the region
with temperatures blow zero this morning over some northern
areas. Northwesterly winds will continue today creating upslope
cloudiness in the mountains. Have introduced a few scattered
snow showers and flurries for the north today. Afternoon high
temperatures will only reach the single numbers in the north to
the teens to mid 20s over the south.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Warm air advection will allow for clouds to increase across the
region tonight. Despite warm air arriving aloft. temperatures
will drop to near zero in the north to the teens in the south
during the evening. Thereafter, models suggest a non-diurnal
curve will lead to temperatures warming during the night.

On Friday, a positively tilted and fast moving short wave
will enter the Ohio Valley. This will bring precipitation to the
region with the high QPF likely over southern areas. The
precipitation type will be mostly in the form of snow. However,
milder temperatures both at the surface and aloft will allow for
the possibility of rain as well over far southern New Hampshire
and perhaps extreme southwestern Maine. Pockets of freezing rain
are possible. A few inches of snow will accumulate in areas
that remain all snow.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
1055 PM...For the period of Saturday and beyond, little changes
made to the forecast, as there`s little evidence to diverge
from the current forecast. A snow in the mtns and snow to rain
on the coast looks centered  around Sunday night, but ensembles
are keeping it mostly a tame event other than it will likely
impact the Monday morning commute.

Previously...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 /08Z THURSDAY THROUGH MONDAY/...
Short Term...VFR Thursday except for some MVFR ceilings and
snow showers at HIE. Conditions gradually lower to IFR and MVFR
tonight into Friday as a weak system passes south of our region.

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 remain place for all areas with the
exception of SCAs in Casco Bay. Freezing Spray Advisories have
continue this morning.

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 until 10 AM EST this morning for
     MEZ007>009.
NH...Cold Weather Advisory until 10 AM EST this morning for NHZ001-
     002.
MARINE...Gale Warning until 11 AM EST this morning for ANZ150-152-154.
     Freezing Spray Advisory until 11 AM EST this morning for
     ANZ150>154.
     Small Craft Advisory until 6 PM EST this evening for ANZ151.

&&

$$
Cannon