668
FXUS61 KGYX 021020
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
620 AM EDT Tue Sep 2 2025

.SYNOPSIS...
Clearer skies and continued fair weather are expected today as
high pressure remains in control. A disturbance moving through
Quebec will bring chances for showers and isolated storms
Wednesday afternoon, mainly north of the foothills. A trough
swinging into the Great Lakes will send a cold front towards New
England Friday that will bring better chances for showers.
Troughing remains over the Northeast into the upcoming weekend
bringing continued chances for showers.

&&

.NEAR TERM /THROUGH TODAY/...
620 AM Update...Just minor updates to align with observations
early this morning as the forecast remains on track. Valley fog
will clear early and clouds will continue to push north out of
the area, making for a clearer day.

Previous Discussion...
Impacts and Key Messages:
* No significant weather impacts are expected.

An upper low continues to slowly move northward, becoming
centered over the eastern Great Lakes Region today which will
push clouds out of the region. Clear skies and deep mixing will
promote another day of drying with relative humidity values
dropping into the 35-45% range during the afternoon.
Temperatures climb into the upper 70s and low 80s south of the
mountains, and into the mid to upper 70s to the north. It is
possible isolated showers and storms pop up near the
international border as southwesterly flow begins to increase
moisture aloft, and this area will be in closer proximity to
the upper low.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
Impacts and Key Messages:
* No significant weather impacts are expected.

Tonight: Clear skies and calm winds will once again allow for
much of the area to decouple and for radiational cooling to
occur tonight, so blended in some lower guidance to account for
this. The result will be temperatures falling into the upper 40s
and 50s areawide. Coastal areas may stay a tad warmer as
increasing onshore flow advects enough moisture to develop low
clouds or fog overnight, most likely in the Midcoast region.
Patchy radiation fog is also likely in the valleys as well.

Wednesday: A shortwave trough moves through the area Wednesday which
will bring about scattered showers and thunderstorms mainly to the
mountains and foothills. The latest CAMs suggest that daytime
heating will lead to a couple hundred joules of CAPE developing
through these areas, with onshore flow keeping points south more
stable. Showers and storms begin developing in the afternoon as the
trough axis swings overhead. Forecast soundings suggest lowering
freezing levels and steepening of low-level lapse rates which would
support small hail and gusty winds in the more robust storms that
may develop. Confidence is low that any may get that strong, so will
leave that enhanced wording out of the grids. At the least,
expect some run-of-the-mill showers and maybe a brief downpour
before showers and clouds begin to dissipate after sunset. High
temperatures climb into the upper 70s to low 80s south of the
mountains, and into the low to mid 70s to the north.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
The incorporation of the 01z NBM yields little change to the
going forecast. The main focus continues to be late week into
the weekend where a couple of short wave troughs that appear to
be amplified enough to tap some moisture which should deliver
some rain to our area. A few thunderstorms will be possible as
well. However, there remains considerable uncertainty in QPF
this far out in time.

Previously...

The 500mb pattern into the first part of the upcoming weekend
will be longwave troughing across the eastern half of the CONUS
with an upper low setting up near the Great Lakes/James Bay
region. A few shortwaves within the longwave pattern will bring
some opportunities for rainfall with higher chances arriving
Friday and Saturday as a couple of shortwaves cross through as
well as a cold front.

Once the Wednesday wave passes, clearing skies and light winds
should allow valley fog to form in some areas with lows
generally in the mid 40s to low 50s.

Shortwave ridging brings dry and mostly sunny conditions for
Thursday, and then this will shift east through late week as the
upper low moves eastward across Quebec and sends a couple of
shortwaves and a cold front through New England. This will
increase shower chances from Thursday night through Saturday
night with thunderstorms also possible during the day on Friday.
GFS/ECMWF ensembles are favoring western and northern NH and
into the foothills and mountains of western ME for the higher
probablilites of over half an inch of rainfall during this time.
Highs looks pretty steady state with highs continuing to be
mostly in the 70s, but overnight lows will be on an upward trend
as southerly flow increases. Marine fog and stratus will also
be possible by late week.

Global models are in pretty good agreement in the last of these
fronts crossing by the early part of Sunday. Should this come
to fruition, Sunday looks to feature a chance of upslope showers
with more clouds in the mountains and partly sunny skies
elsewhere. Building high pressure looks to bring further drying
into early next week.

&&

.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
Short Term...Valley fog clears this morning, with VFR
prevailing at all terminals through the day. Fog will then
return to the valleys Tuesday night with low ceilings/fog also
developing along the coast. This seems most likely at RKD, but
other terminals like PWM, PSM, and even over to AUG may see this
as well. Scattered showers and thunderstorms are possible on a
line from LEB to AUG and points north on Wednesday afternoon,
but outside of that VFR will prevail again.

Long Term...Patchy fog and/or low stratus Wednesday night into
early Thursday. Mainly VFR during the day Thursday, but an
approaching cold front will bring increasing precipitation
chances Friday into Saturday. Outside of showers, low ceilings
and fog will also be possible ahead of the front with the
increase in southerly flow and moisture.

&&

.MARINE...
Short Term...Winds and seas remain below SCA criteria through
Wednesday. Winds will generally be southerly, with gusts less
than 15 kts. Seas will be generally 1-2ft today, but low
pressure approaching the eastern Gulf of Maine will build them
up to 3ft by Wednesday.

Long Term...High pressure will be in control Thursday but will
shift to the east of the waters Friday into Saturday as a cold
front approaches from the west. There may be a period of SCA
conditions as southerly flow increases ahead of the front as
well as increasing potential for marine fog and stratus. The
front looks to cross the waters Saturday night and into early
Sunday with conditions likely remaining under SCA conditions as
high pressure builds in across the Northeast into early next
week.

&&

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

&&

$$

NEAR/SHORT TERM...Baron
LONG TERM...Combs/Ekster