882
FXUS61 KGYX 171830
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
230 PM EDT Thu Sep 17 2026

.WHAT HAS CHANGED...
High resolution models have become a little bit more optimistic
with regards to pockets of heavier rain this evening across portions
of southern New Hampshire and southwest Maine.

&&

.KEY MESSAGES...
1. A quick moving low and front will lead to increasing rain
chances this afternoon through the first part of tonight.
Expect some gusty winds behind the front on Friday afternoon.

2. Another rainy Sunday will be followed by mostly dry weather
through much of next week, with temperatures running near to
slightly below normal.

&&

.DISCUSSION...
KEY MESSAGE 1 DESCRIPTION...

As an upper level shortwave approaches, a weak surface low will
move from eastern New York early this afternoon to the southern
New Hampshire/Maine border by the evening. These features will
lead to increasing rain chances later this afternoon before
expanding north and east into western Maine through the first
part of tonight. The highest chances (60 to 90 percent), will be
along the track of the low and trailing cold front, which
should move across southern New Hampshire and into portions of
the western Maine Foothills, the Interior, and the coast. CAMs
have come into fairly solid agreement on the track of heavier
showers and RAP soundings suggest that we could see some MUCAPE
around 100 J/kg. Thus, there will be a convective element to
this precipitation which may lead to some pulsey embedded
downpours. A rumble of thunder or two can`t be ruled out,
either. Best guess is that we will see the higher totals in the
0.5 to 1 inch range which matches well with what the 12z HREF
mean is advertising, but HREF 24-hour max QPF does suggest the
potential for some 1.5 to 2 inch totals. Thus, some locally
higher totals will be possible depending on how convection
evolves. Rain will then move out quickly overnight as the low
moves into the Gulf of Maine.

Behind the cold front, we should see plenty of sunshine and a
stiff breeze on Friday. While pressure rises are not overly
impressive, we will see some decent cold air advection and steep
low-level lapse rates. Forecast NAM and GFS soundings suggest
that we will see 30 to 35 knots at the top of the mixed layer so
with the favorable lapse rates, widespread gusts in the 25 to 35
mph range seem reasonable. The strongest winds appear to be most
favorable over Maine. Gusty winds could lead to a limited power
outage threat from any branches that come down. Winds will
diminish rather quickly around and after sunset Friday evening,
becoming calm overnight. While we could still have some
lingering high clouds around, we should have some areas that
will see favorable conditions for radiational cooling.
Overnight lows may dip into the low to mid 30s along and north
of the mountains, with values in the upper 30s to mid 40s
elsewhere. Some areas of frost will be possible across the
north.

KEY MESSAGE 2 DESCRIPTION...
High pressure slides through the region Saturday which will
make it the pick of the weekend. Upper level troughing drops 850
mb temperatures to +2 to +5 C, so it is going to be on the
cooler side with highs capping out in the low to mid 60s. Clouds
increase Saturday night as a shortwave moves through the
broader trough toward our area and high pressure begins to push
offshore. Temperatures fall into the mid to upper 30s north of
the mountains, and into the low to mid-40s south.

High pressure continues to stay nosed in through Sunday
morning, but rain moves into New Hampshire by Sunday afternoon
as a wave of low pressure takes a track through southern New
England. This creates some uncertainty in the northward extent
of the precipitation shield, but forcing from the shortwave
should be enough to get measurable rainfall up through most of
the area. The higher rainfall totals are likely going to fall
south of Concord where better forcing is going to overlap with
higher moisture. NBM is currently advertising probabilities of a
half inch around 40 to 50 percent in that area.

Rain wraps up overnight and by late Monday morning most of the
area should be back under mostly sunny skies. Global models are
in good agreement that strong high pressure builds and then
settles over the region through most of next week. This brings
mostly dry conditions with daytime temperatures in the 60s.
Nighttime temperatures are mostly going to be seasonable as well
(ranging from the upper 30s in the north to 40s in the south),
but high pressure overhead usually allows for radiational
cooling and I would not be surprised if we see frosts in
northern zones more than once.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
For the rest of the day, MVFR cigs are possible with fog and
marine stratus potentially bringing IFR to PWM and RKD as early
as this afternoon. Elsewhere, cigs lower to MVFR through the
afternoon with increasing chances for rain showers, and then
ceilings further lower to IFR or lower at most sites through
tonight with fog and -SHRA continuing. A rumble of thunder or
two cannot be ruled out. Showers end west to east overnight, but
fog may prolong IFR or lower restrictions at some terminals
through daybreak Friday.

Outlook...
Saturday-Saturday night: Generally VFR with ceilings thickening
and lowering after 06Z Sunday.

Sunday-Sunday night: Generally MVFR expected by early Sunday
morning and then prevailing as rain moves through the area. Rain
then begins tapering off Sunday night.

Monday-Tuesday: MVFR early, improving to VFR. Generally VFR
conditions are then expected through at least Tuesday.

&&

.MARINE...
Winds and seas are generally expected to remain below SCA
thresholds through the remainder of the forecast period. However
a modest cold front will cross the waters Fri and northwest
winds will become gusty during the day. While guidance does not
quite show it at this time, I would not be surprised to see a
few 25 kt gusts at times. There will also be areas of fog
developing ahead of a frontal wave today and that fog may move
into bays and inlets towards late afternoon or early evening.

Generally sub-SCA conditions are expected from Saturday through
much of next week. Low pressure tracks south of the Gulf of
Maine on Sunday which may create some brief SCA conditions.
Otherwise, high pressure builds and settles over the region
beginning Monday.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.

&&

$$

DISCUSSION...Hargrove/Baron