418
FXUS61 KGYX 031757
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
157 PM EDT Wed Sep 3 2025

.SYNOPSIS...
A disturbance moving through Quebec will bring chances for
showers and isolated storms this afternoon, mainly north of the
foothills. A trough swinging into the Great Lakes will send a
cold front towards New England, bringing increasing chances for
showers Thursday night into Friday. Another front approaches for
Saturday perhaps allowing for more substantial rainfall and
thunderstorms over a wider area. High pressure moves in early
next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Latest RAP13 analyzes a 500mb shortwave in the process of moving
across northern New England. Lift from this trough will continue
to kick off scattered showers and storms in the mountains this
afternoon with more isolated coverage farther south toward the
foothills where subsidence increases and moisture is less
favorable. Forecast soundings reveal pretty low freezing levels
at around 7,500 ft AGL, and with a few hundred J/kg of CAPE,
storms could produce small hail. Dry low levels will also
support a gusty wind threat. Showers and storms will wane this
evening with the loss of daytime heating and as the trough lifts
off to the north and east.

Skies are expected to clear out behind the wave tonight with
good radiational cooling with lows in the mid 40s to lower 50s
for most. Valley fog is again expected tonight, and guidance is
hinting at higher fog coverage (and potentially dense) across
western ME from the coast to the foothills, where I have opted
for "areas" wording rather than "patchy".

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
Once the fog lifts by 9 AM or so Thursday morning, shortwave ridging
will move overhead and bring a dry and mostly sunny day. Southerly
flow will be increasing ahead of a frontal boundary with somewhat
breezy conditions of 20-25 mph at times. Highs will again be in the
mid 70s to low 80s for much of the region, although the Midcoast may
be a few degrees cooler with the winds directly off of the Gulf of
Maine.

A shortwave will continue to push the frontal boundary toward New
England Thursday evening. Moisture will steadily increase, but there
will still be some dry air to overcome initially. I have slowed
the onset of rain showers slightly, but western NH should start
seeing precip by late evening to around midnight with a north
and eastward expansion through Thursday night. Highest amounts
and chances will be across western and northern NH extending
into the western ME mountains and foothills where 0.10" to 0.25"
of rainfall will be possible by daybreak Friday. More fog is on
the forecast with guidance favoring western ME, where it could
be dense in some areas.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
A broad upper-level low over eastern Canada and mid-level
troughing will allow for a few periods of rain and storms
through the weekend.

The first arrives Friday morning, though showers are bound to be
more scattered once they arrive in NH and Maine. This is because mid-
level troughing present is situated to the west and nearly uniform
SW winds aloft should usher in drier low-level air. This drier air
will be short lived, as it moves eastward and a stream of low-level
moisture originating from the remnants of Eastern Pacific TC Lorena
flows into the Northeast. This flow of moisture should continue
through the weekend, and daytime heating Saturday morning should
allow for convective initiation in the afternoon. Storms should
have ample moisture to work with from the aforementioned
moisture stream and heavy downpours appear possible with some
storms that develop. Gusty winds might be a possibility as well,
with some forecast soundings already showing 30-40kt winds
could down to the surface.

The upper-level low shifts eastward Sunday morning, and conditions
start to improve on Sunday as dry air works in from the west
throughout the day. High pressure works into the area next Monday,
with it likely sticking around through the week. Very dry and cool
conditions are expected, with high temperatures in the mid-70s.


&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
Short Term...Can`t completely rule out a brief shower/storm at
HIE and AUG this afternoon, but chances are too low for TAF
inclusion. Otherwise, expect fog development again tonight,
especially at RKD-AUG and LEB- HIE...where IFR-LIFR restrictions
look likely. Once fog clears out Thursday morning, all should
see prevailing VFR during the day, but it will be on the breezy
side with southerly winds gusting to around 20 kt. Fog and low
stratus are again possible Thursday evening and night with
increasing chances for showers.

Long Term...
Lowered restrictions are expected on Friday, with restrictions
continuing through Sunday morning. VFR expected Sunday through the
end of next week.
&&

.MARINE...
Short Term...Winds will be primarily southerly today through Thursday
night, which will increase gradually Thurs-Thurs night as a cold
front approaches from the west. However, winds and seas are expected
to remain below SCA levels with wind gusts expected to remain around
20 kt. Marine fog and stratus remains possible, especially east of
Portland and Cape Elizabeth.

Long Term...
Southerly winds are expected on Friday, with winds and seas
increasing to SCA thresholds by the end of the day. These conditions
are likely to continue through the end of the day Saturday. Seas
lower to 2-4ft and winds shift to westerlies Saturday night. Winds
will also weaken to 4-8kts by daybreak Sunday. Mostly light and
variable winds, with seas of 2-4 feet are expected through most of
next week.

&&

.FIRE WEATHER...
Southerly winds will increase Thursday with gusts of 20 to 25
mph possible. These winds combined with RH falling to 35 to 40
percent over much of NH and 40 to 50 across interior Maine could
make for increased fire sensitivity.

&&

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

&&

$$

NEAR TERM...Combs
SHORT TERM...Combs
LONG TERM...Palmer
FIRE WEATHER...Combs