994
FXUS61 KGYX 220332
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1032 PM EST Tue Jan 21 2025

.SYNOPSIS...
Bitterly cold air remains entrenched across New England for the
next couple of days. Tonight will be another clear and mostly
calm one, allowing temperatures to fall below zero for most
locations and double digits below zero in the northern valleys.
Temperatures will slowly moderate the rest of the week with
chance for snow showers at times but not much more than that.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
0232Z Update...

Have lowered temperatures and dew points once again with this
impressive Arctic airmass. Clear skies, calm winds, low dew
points and a fresh snowpack will allow for temperatures to drop
to 20 to 25 below zero across the north with temperatures near
or below zero all the way to the coast. This has lead to an
expansion of Freezing Spray Advisories for the coastal waters.

Latest webcams continue to show a few snow flurries in the far
north. Otherwise, very dry with low dew points expected
overnight across northern New England with the 00Z GYX sounding
obviously very dry as well. There are some clouds crossing the
region from time to time so temperatures may vary significantly
from location to location by morning. In any case, temperatures
have already fallen below zero in northern areas.

Prev Disc...
Mid and high clouds streaming in across the south and coast
associated with an upper-level jet will exit to the east this
evening...along with the diurnal stratocu dissipating. The
mountains may hang on to more clouds for a little longer but
should eventually clear out.

Winds will diminish after sunset this evening, again setting up
very good conditions for radiational cooling with the freshly
fallen snow. Based on last night/this morning and dewpoints
being lower than this time yesterday, the forecast lows are
colder than all guidance with lows forecast in the mostly in the
-5 to -10F range with some of the normally cold spots
 potentially reaching -10 to -15F. In the mountains, forecast
 lows are in the -10 to -20F range, and with wind chills a few
 degrees colder, have went ahead and issued a Cold Weather
 Advisory for Coos county in NH as well as around the Western
 Maine Mountains. An upper wave will move through basically
 unnoticed tonight with no moisture to work with.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
High pressure continues to expand toward the Eastern Seaboard on
Wednesday as the upper wave that moves through tonight quickly
exits. We`ll still have the same very cold and dry airmass, and with
the impending high pressure winds will be less breezy than those of
today but still occasionally gusting up to 15-20 mph. Mostly
sunny skies are expected with more in the way of mid/high clouds
starting to show up late in the afternoon out ahead of an upper
trough over the Great Lakes.

Clouds are expected to lower and thicken Wednesday evening and
overnight ahead of the upper trough, and these will play a role in
how cold or not as cold it gets. Confidence is pretty high that
temperatures will level off or even come up a bit at some
point, but how quickly this occurs is the key as there still may
be a period of good radiational cooling early on. I have
followed a non-diurnal trend in the forecast with low
temperatures possibly occurring in the evening or early
overnight. South of the mountains, I have lows in the positive
single digits to teens while up north lows could still dip into
the negative single digits to lower teens. There may also be
some flurries here, but the low levels will be pretty dry. The
exception may be the Midcoast, where low-level winds bring in
some extra moisture off the ocean, and I have included 20% PoP
there.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Late evening update...
Relatively dry conditions expected throughout the extended
portions of the forecast with swings in temperatures continuing.

Arctic cold will remain over the forecast area Wednesday night
under light winds. However, warm air advection aloft will allow
for some clouds to build in the area. Nevertheless, expect
below zero temperatures in the north with single numbers in the
south.

A return southwesterly flow behind the departing high pressure
system will allow for a mix of sun and clouds with temperatures
mostly in the 20s on Thursday, but back into the single numbers
Thursday night as a cold front crosses the region, again
relatively dry with the exception of a few upslope snow showers
in the mountains.

Latest operational model guidance and ensemble solutions suggest
seasonably cool conditions will remain over the region Friday
and Saturday. It will remain repeatedly dry for a vast majority
of the forecast area.

A cold front will then cross the region on Sunday into Sunday
night as our drought conditions persist.

Prev Disc...
Key Message: While warmer than the last couple of
days temps will remain near to below normal thru he extended.
Offshore winds will be the predominate direction and below
normal precip is likely.

Impacts: No significant weather impacts anticipated thru the
early next week.

Forecast Details: Not much detail to differentiate the extended this
afternoon. The overall trend remains near to below normal temps with
more westerly flow than typical for this time of year. That westerly
flow will moving around a lot of continental air...and at best we
will be left with some residual Pacific moisture. So drier
conditions are anticipated. The best bet will be with upslope snow
showers...but passing S/WV trofs may be able to bring more
widespread snow shower activity. At this time that looks like it
could be around the Mon timeframe.

I did adjust Fri night min temps down a bit...closer to MOS
readings...as there is some suggestion that surface ridging may work
into the area before the upper trof reloads. Otherwise no
significant changes from the NBM.

&&

.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Short Term...VFR today through Wednesday night with only a low
chance of a snow shower and/or MVFR ceiling at HIE this
afternoon/early evening.

Long Term...VFR conditions are expected to prevail for much of the
extended. There may be periods of MVFR CIGs in the vicinity of
HIE...but the overall moisture starved pattern should keep them from
being frequent and/or prolonged.

&&

.MARINE...
Short Term...Winds and seas continue to ease through tonight
and Wednesday and remain below SCA levels. High pressure shifts
east Wednesday night with SW flow starting to increase
late...but still remaining below 25 kt. Light to moderate
freezing spray will continue over the coastal waters.

Long Term...Cold air masses and westerly flow will likely mean at least
SCA conditions are possible for much of the extended. A brief break
is possible late this week...but gusty offshore winds are expected
as soon as cold advection begins again.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Cold Weather Advisory from midnight tonight to 10 AM EST
     Wednesday for MEZ007>009.
NH...Cold Weather Advisory from midnight tonight to 10 AM EST
     Wednesday for NHZ001-002.
MARINE...Freezing Spray Advisory from 3 AM to 10 AM EST Wednesday for
     ANZ150-152.

&&

$$

Cannon