Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 241939
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
339 PM EDT Sun Mar 24 2024

.SYNOPSIS...
A cold night is in store tonight, with cooler than normal
temperatures and quiet weather persisting through the start of
the week. Temperatures are expected to moderate to near seasonal
norms later in the week, but it does come with unsettled,
showery weather weather as a series of weak waves interact with
a slow-moving front. Dry weather likely returns for next
weekend.

&&

.NEAR TERM /TONIGHT/...
Latest RAP13 pressure analysis this afternoon shows high
pressure located over Quebec with a nearly stationary area of
low pressure well to the east of the Mid-Atlantic. Satellite
imagery shows some thin high-level clouds skirting the ME and NH
coast and extending about 20 or so miles inland. Current
temperatures are primarily into the middle to upper 30s south of
the mountains with a few upper 20s lingering over the north and
higher elevations. Northerly winds continue but are already
showing signs of weakening as the pressure gradient diminishing.
It will continue to be a dry and cool afternoon and evening
with temperatures falling quickly towards sunset.

Surface high pressure will build to our north tonight as 500-mb
ridging moves overhead. This will allow for weak winds and given
the fresh snowpack and dry airmass in place, strong radiational
cooling is expected to occur. The greatest cooling will likely
be inland from the coast as most locations decouple and skies
will be the most clear. Along the coast, high-level clouds
could linger through at least part of the night, tampering
cooling some. As a result, used MOS guidance for overnight lows
and went even a little colder in the valleys. This places lows
into the single digits either side of zero in the normally
colder spots with lower to middle teens elsewhere.

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
High pressure will remain overhead on Monday, allowing for
another day of tranquil weather conditions. Skies will be clear
to partly cloudy with northeasterly winds of 10-15 mph, gusts to
around 20 mph. Temperatures aloft will warm some from today and
this combined with afternoon mixing will push high temperatures
into the upper 30s to lower 40s south of the mountains with
mid-30s across the north and the mountains themselves.

Clouds will begin to increase on Monday night from southeast to
northwest as a frontal system approaches from the east. Any
associated precipitation should hold off until Tuesday though as
forcing remains well offshore and it will take some time to
saturate the column. Lows will range from the teens across the
northern valleys where it will stay clear the longest to the
20s/low 30s further to the south and along the coast.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
The cool pattern over our area trends toward a milder and
unsettled one later this week, as a series of weak systems
interact with a front slowly crossing the region. High pressure
to our north will keep a steady feed of drier, cooler air at the
surface to attenuate the warmer, more humid air mass moving in
aloft, so while it will certainly warm up, we`re not expecting a
blow-torch sort of pattern. And although we`re not expecting a
washout, it`s likely to be a showery period and we`ll have to
keep an eye on any sort of phasing that may occur with these
systems which could potentially lead to more noticeable
precipitation amounts. The front eventually exits, with the
model suite indicating drier conditions likely over the weekend.

Starting on Tuesday...a stout 1042 MB high will be located over
Newfoundland/Labrador while cut-off low pressure spins over the
Atlantic east of the Carolinas, and another low tracks into the
Great Lakes...resulting in a narrow ridge extending south down
the Atlantic Seaboard. The result is a cool NE flow at the
surface, however at the same time the Atlantic low sends an
inverted trough into New England which provides increasing mid-
level warmth and moisture. The trough at the very least
contributes an overcast or broken overcast cloud deck, which
would help to keep temperatures cooler on Tuesday, with 30s to
near 40 readings at best south and east of the mountains and
toward the coast.

I`m somewhat dubious WRT the potential for drizzle on the front
end of the push of moisture given the drier NE feed, however
later in the day deeper moisture arrives from the SE... enough
to produce some showers by the afternoon and through the
overnight. Given the clouds, and the CAD in place, I`m seeing
potential for light freezing rain in the CAD, primarily in the
Maine foothills which is a preferred area for the CAD to lock in
from a climatological perspective. The good news is that QPF
doesn`t appear to be all that impressive, which just a few
hundredths up to a couple tenths to offer, ultimately limiting
the amount of icing potential. But, there could still be some
slick travel through the western Maine foothills. Tuesday
through the night.

With this wave exiting north and east on Tuesday, a cold front
will gradually approach New England on Wednesday with increasing
baroclinicity and more chances for rain showers. It will be
another mostly cloudy or overcast day, and likely a little bit
warmer with diminishing NE flow with highs right now in the 40s
to around 50. Overnight ought to be on the mild side with a
blanket of clouds and increasing dew points, only getting down
into the 30s or even only 40 in some places with, as current
model consensus suggests, the front entering the area from the
west. This will provide a focus for more rain activity...
continuing into Thursday as the front drifts offshore.

In general, the front continues to slowly drift east, likely
situated in the central or eastern Gulf of Maine on Friday...
before an upper level trough axis approaches and quickly spins a
low up along the front. Ensemble solutions currently favor the
brunt of this wave to remain offshore, or to the east in
general, however there is still a window of potential impacts
should that wave develop further west than current consensus.

High pressure builds behind the departing low pressure system
for the start of the weekend with gusty northwest winds, and
strong mixing allowing temperatures to remain in the 30s north
to near 50 south in spite of a significantly cooler airmass
coming overhead. The trend continues into Sunday, but with a
little lighter flow given a more relaxed PGF by then. One
potential fly in the ointment is that the northern stream will
remain active through this time, so can`t entirely rule out a
quick-hitting clipper late in the weekend.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
Short Term...VFR conditions will prevail tonight through Monday
night as high pressure builds to our north. Northerly winds will
become light and variable tonight and then out of the northeast
at 10-15 kts with gusts to 20 kts on Monday before weakening
again Monday night. No LLWS is expected.

Long Term...MVFR or IFR in low CIGs are likely to develop for at
least coastal sites on Tue, expanding in coverage except into
the CT River Valley into Wed with increasing SHRA potential.
Restrictions are likely to prevail through the passage and exit
of a front late in the week.

&&

.MARINE...
Short Term...Seas will remain elevated through the period
outside of the bays at 4-10 ft due to distant offshore low
pressure. North- northeasterly wind gusts up to around 25 kts
will remain possible as well outside of the bays.

Long Term...Steady NE flow persists over the waters with gusts
mainly between 25 and 30 kts Tue night coinciding with seas
generally 7-10 ft. Flow diminishes and turns out of the SE Wed,
with seas remaining relatively elevated at 5-8 ft. Winds then
turn gusty out of the NW behind a front Thu into the weekend,
gradually strengthening, perhaps to a strong SCA or low-end
gale.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 6 AM EDT Tuesday for ANZ150-152-154.
     Small Craft Advisory until 8 PM EDT this evening for ANZ151-
     153.

&&

$$

NEAR TERM...Tubbs
SHORT TERM...Tubbs
LONG TERM...Casey


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