Seabrook, New Hampshire 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

826
FXUS61 KGYX 261045
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
645 AM EDT Thu Jun 26 2025

.SYNOPSIS...
Mostly dry conditions will prevail today into Friday, although
a front southwest of New England could lead to light some
showers at times across New Hampshire and southwest Maine.
Chances for showers increase late Friday with a soaking rain
Friday night into Saturday as low pressure crosses New England.
Weak high pressure will bring a drying trend Sunday into Monday
with temperatures and humidity increasing ahead of a cold front
Tuesday.


&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

645AM Update...Mainly focused on cloud cover with this update but
no big changes needed.

Previous...

High pressure extends from southern Canada through New England early
this morning with a cooler and drier airmass now in place, offering
a much more comfortable start to the day. Temperatures are in the
50s to 60s over much of the area, but more cloud cover across
southern NH just north of a weak frontal boundary has been more
persistent than previously modeled, keeping temperatures warmer
there. High clouds are also starting to move in farther north.

For the rest of the day, temperatures will remain comfortable with
highs in the 70s, but the seabreeze will likely move inland
this afternoon, which will cool temps down into the 60s where it
crosses. Southern NH will hang on to at least some of clouds
this morning, and the high clouds are expected to lower and
thicken for most of the area as the day goes on. There will be
some weak lift present to where there could be a few light
showers or sprinkles across NH and SW ME, but the low levels are
forecast to remain pretty dry. This should keep amounts very
light and limited to a few hundredths of an inch or less.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Tonight, skies are expected to remain mostly cloudy over much
of New Hampshire into southwest ME where there will also be a
continued low chance (20-30%) of light showers or sprinkles.
Areas that stay cloudier will probably see temps stay in the 50s
to low 60s. Farther to the north and east, expect some clearing
where the airmass is drier, and those that are able to clear
out more are likely to see temperatures in the 40s.

The high pressure that will be over the area today and tonight will
shift to the east as low pressure approaches from the Great Lakes.
NH is expected to have most of the cloud cover in the morning
with more cloud cover then spreading east, especially going
through the afternoon as the low and warm front approach the
area. Temps will be cooler for western areas but am still
expecting eastern areas to reach the 70s where there is less
cloud cover early in the day.

Shower chances gradually trend upward from west to east through the
day as lift and moisture increase, but there remains a fair amount
of spread in the guidance in how quickly the high departs and the
better moisture and lift arrive. With the exception of the GFS,
there does seem to be a trend in a lot of guidance in holding
onto some drier air aloft and delaying the onset of precip. So
I have trended PoPs downward from the previous forecast through
much of the day, especially across southern and eastern areas,
and this may need to be done moreso in future updates. Still,
the northern half of NH and NW ME have the highest chance of the
day (50-60%) with the highest chances arriving Friday evening
and Friday night.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Evening Long Term Update... the 01z NBM has been incorporated
into the latest forecast and yielded little change to the
overall idea that cooler and wetter conditions will be the norm
Friday night and Saturday. However, locations of heavier
precipitation are hard to pin down at this time as convection
will likely be involved. The greatest forcing for ascent
continues to be forecasted across our mountain zones Friday
night and Saturday. And this is where our highest PoP and QPF
forecast continues to be for the time being.

Previously...

Low pressure approaching from the Great Lakes will bring periods
of rain Friday night into Saturday morning. Precipitation
chances will gradually diminish Saturday night through Sunday as
the low pressure system exits into the Atlantic. Weak high
pressure builds in Monday for mostly dry conditions with
increasing temperatures. A deeper trough will approach Tuesday
with temperatures continuing an upward trend with increasing
humidity ahead of a cold front. Latest guidance is in decent
agreement that this cold front will cross the region near or
just after peak heating favoring the development of
thunderstorms.

A period of cooler and cloudier weather is looking likely from
Friday night into Sunday. The 12Z model suite brings a surface
low WSW to ESE across New England Friday night into Saturday
morning. This will likely bring a widespread soaking rain to
much of the area. PWATs will be on the increase Friday night
approaching 1.75 inches by Saturday morning along with warm
clouds depths greater than 12KFT. The track of the low will keep
the best instability well to the south of the area that should
preclude rainfall rates from reaching their full potential given
the high PWATs and deep warm cloud depths. Current QPF forecast
from Friday through Saturday is around 0.75 to 1.25 inches
south of the mountains with 1.5 to 2.25 inches across the
mountains and north. WPC has the forecast area in a Marginal
Risk for excessive rainfall through the duration of the event,
which seems reasonable given the high PWATs but lack of
instability. Steady rain will transition showers late Saturday
into Saturday night with highs on Saturday mainly in the 60s.

Low pressure will be offshore by Sunday while subtle waves aloft
will keeps low chances for showers in the forecast. Highs on Sunday
will range from the upper 60s north to mid 70s across the south.
Weak high pressure will build in for mostly dry conditions Monday
with highs climbing into the 80s. Temperatures and dewpoints will
continue to rise into Tuesday that will foster an unstable airmass
ahead of an approaching cold front. Models are in good agreement at
this time range that a front will cross sometime Tuesday afternoon
through Tuesday night that will bring chances for thunderstorms.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
Short Term...Expecting an increase in cloud cover through the
day today, but ceilings are expected to remain VFR. This will
bring a low chance of showers across NH and SW ME, and a few
showers remain possible across southern NH tonight and into
Friday morning...and can`t completely rule out patchy fog if
skies are able to clear out. Higher shower chances arrive later
in the day on Friday with MVFR ceilings possible by late
afternoon or early evening.

Long Term...Clouds thicken and lower Friday night with RA
likely bringing at least periods of MVFR into Saturday morning.
Conditions will improve some late Saturday into Sunday morning
with a return to prevailing VFR Monday.

&&

.MARINE...
Short Term...Conditions are expected to remain mostly below SCA
levels today through Friday, although there may be a brief
period of winds near 25 kt across the southern waters this
morning. High pressure centered to the north will start winds
out of the NE this morning, but these could be more variable at
times this afternoon as a seabreeze tries to develop. Winds will
be light and variable with the high overhead tonight, but
approaching low pressure will shift the high to the east on
Friday, returning winds out of the south to southeast.

Long Term..A low pressure crosses Friday night and Saturday.
This system will bring increasing easterly flow with winds
generally below 25 kts. The persistent easterly flow will bring
seas to 5 feet Saturday into Monday.

&&

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

&&

$$


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