Brunswick, Maine Weather Forecast Discussion

874
FXUS61 KGYX 211216
AFDGYX
Area Forecast Discussion
National Weather Service Gray ME
816 AM EDT Sun Sep 21 2025
.SYNOPSIS...
High pressure crests over the area this morning and drifts
offshore through Monday. Temperatures will be on the rise
through Tuesday before a cold front slowly sinks south into New
England. This front will bring chances for showers and perhaps a
needed wetting rainfall as a wave of low pressure tracks along
the front Tuesday and Wednesday.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
8am Update...Quick update to expire frost/freeze headlines. A more
mild night ahead tonight, but still may have some patchy frost
development in the valleys north of the Whites. Will assess this
today.
Previous Discussion...
Nighttime microphysics satellite imagery early this Sunday
morning shows clear skies across northern New England with the
latest RAP pressure analysis showing a ~1030 mb sfc high
directly overhead. These clear skies, calm winds, and low dew
points are as expected allowing for textbook radiational cooling
conditions across the region. Current temperatures range from
the upper 20s across some northern valleys with 30s across much
of the interior and then 40s along the coast and in the urban
corridors. Additional cooling can be expected through sunrise
with freeze warnings and frost advisories remaining in effect
for portions of the region through 8am local time.
Sfc high pressure will begin to drift east today over the Gulf
of ME, allowing for developing southerly return flow. Sunny
skies will prevail through at least the first half of the day
before some cirrus arrives this afternoon and evening. High
temperatures will range from the upper 60s to lower 70s in most
locations.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
Dry conditions will persist tonight with just some high-altitude
cirrus passing overhead. Went ahead and lowered forecast lows a
little below the NBM as high-lvl clouds tend to not have a big
impact on radiational cooling. It still won`t be as cold as
previous nights though as sfc dew points will be a little
higher. Forecast lows range from the middle 30s across some
inland valley locations with lower to middle 40s elsewhere.
Valley fog will once again be possible overnight into early
Monday morning.
Monday looks to remain dry as high pressure exits off to the
east and a frontal boundary begins to approach from the west.
Partly sunny skies will prevail with high temperatures mainly
into the 70s, which is a little above avg.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
01Z NBM Update...A cold front will slowly sag into northern New
England Tuesday and a wave of low pressure may form along the
front and track across the area Tuesday night. The front will
linger over the area through Wednesday continuing chances for
showers. The latest NBM has slightly increased PoPs and QPF
during the Tuesday to Wednesday timeframe. However, QPF remains
rather light and will likely not put much of a dent into ongoing
precipitation deficits.
Previously...
Key Message: Chances for rain showers increase mid to late
week...but localized nature means that drought likely continues to
deepen. Temps return to near to above normal.
Impacts: No significant weather impacts anticipated beyond
maintaining/deepening drought conditions.
Forecast Details: It is a quiet beginning of the week...but high
pressure will be slipping east and return flow will be underway.
While most of the period will be near to above normal Tue will have
the chance to be well above normal. Tue should see high temps
approaching 80 across southern parts of the forecast area.
Then attention will turn towards a cold front dropping into the
region from the northwest. Upper trof will be digging thru St.
Lawrence Valley Tue into Wed...so I anticipate the front will be
able to make its way thru the region. I do not anticipate much
more than showers with the boundary however. There is some
indication that western Atlantic ridging reestablishing itself
and Midwestern trof may combine to stall the tail end of the
frontal boundary. That could provide a focus for more showers
Wed into Thu. Looking at the cluster analysis via DESI...this is
roughly 25 percent of ensemble members. But that is enough for
chance PoP...which is what the NBM guidance currently forecasts.
I would prefer it if PoP was not smeared out over 3 days or
so...because much of that will be dry...but I cannot rule out
precip on any of the days given the pattern. So I will leave the
PoP as is...but continue to message deepening/worsening drought
conditions.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
Short Term...Other than valley FG at KLEB, KHIE, and perhaps
KCON through around 12Z this morning, VFR conditions will
prevail today. Light and variable winds will increase to 5-15
kts out of the south this afternoon. Winds become light and
variable tonight with valley FG/restrictions possible at KLEB
and KHIE. VFR conditions then return on Monday with S-SW flow at
generally 5-15 kts. No LLWS is anticipated through the period.
Long Term...Largely VFR conditions expected in the extended. A
passing front will bring the threat for SHRA and local MVFR or lower
conditions...but activity is not expected to be widespread at this
time. There is a low (25 percent or less) chance of an additional
round of rain moving across southern parts of the forecast area Wed
which is why the forecast has PoP for much of the week beyond Tue.
However most of that period will be dry with small windows for
potential rain.
&&
.MARINE...
Short Term...High pressure will remain near or over the waters
through Monday with generally light S-SW winds and low seas of
2-3 ft.
Long Term...Winds and seas are anticipated to remain below SCA
thresholds. Swell from Gabrielle arrives midweek and seas may
build to around 5 ft. The period will be 10 to 15 seconds and
not expected to be hazardous to small craft outside of typical
shoaling areas.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
&&
$$
NEAR TERM...Cornwell/Tubbs
SHORT TERM...Tubbs
LONG TERM...Legro/Schroeter

NWS GYX Office Area Forecast Discussion