Seabrook, New Hampshire 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

685
FXUS61 KGYX 071935
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
335 PM EDT Sat Jun 7 2025

.SYNOPSIS...
A localized flooding threat continues into early this evening as
slow-moving showers along with a couple of storms remain across
the areas. A break arrives Sunday as high pressure briefly
builds. Conditions become unsettled next week with widespread
showers Tuesday into Wednesday. Improving conditions are then
expected for the second half of the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Impacts and Key Messages:
* The Flash Flood threat diminishes this evening as rain rates
  weaken and precipitation clears the area

The back edge of the bulk of the rain has sunk south of the
mountains at this hour. This line was a bit more progressive
than what was being advertised by models over the last couple
days which was a huge positive in regards to the flash flood
threat. Still, there were embedded heavy showers with rates of
1-2 inches at times and these tracked over already saturated and
urban areas prompting the need for a Flash Flood warning and
some advisories that are still in effect. I back off on the
thunder with this forecast package as lightning has failed to
materialize so far. However, I did not fully take it out, as a
trailing convective line currently in Canada may stay together
and move into northern New Hampshire and the Western Maine
Mountains. The larger heavy rain threat is on it`s way out with
the latest hi-res guidance clearing the frontal boundary by
8PM. The Flood Watch remains unchanged and will likely be
allowed to expire with the next update.

With moist antecedent conditions and clearing skies, I would
expect at the least some patchy fog to develop overnight. A more
moist airmass over the waters will lead to dense fog which may
advect onto the coast as well. Dewpoints remain on the higher
side tonight so even with clearing skies low temperatures only
fall into the mid 50s for the interior and upper 50s for the
coastal plain. North of the mountains will see low 50s and maybe
even upper 40s in the sheltered valleys.

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
Impacts and Key Messages:
* No significant impacts expected

High pressure builds in from the north on Sunday which will mix
out any lingering fog and start us off clear and dry. By the
afternoon we will see clouds approaching from the south as waves
of low pressure ride along a frontal boundary offshore. The
latest hi-res models suggest this wave may touch off some
isolated showers Sunday afternoon, but with a dry air mass
freshly built into the region I`m not convinced. Even with clear
skies leading to some diurnal instability, I think the dry air
intrusion will be too much to overcome in the mid-levels. Good
mixing and 850mb temperatures in the +7-9C range will put high
temperatures in the 70s areawide.

Sunday night will be a little bit of a different story as low
pressure moves closer to the coast. Between upper level
southwesterly flow and onshore low level flow, moisture will be
advecting into the region overnight increasing cloud cover. As
we head toward sunrise chances for showers will increase across
southern areas too. Cloud cover will keep low temperatures in
the low to mid-50s.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Mostly but not completely dry conditions are expected Monday with
high pressure located near the Maritimes and low pressure south of
the area. A tight moisture gradient will set up with drier air to
the north and east with the higher moisture over southern and
western portions of the area. Where the higher moisture is found
expect cloudier skies and 20-30% shower chances for at least the
first part of the day with less cloud cover to the north and east.
Temperatures will be mostly in the mid 60s to low 70s, but southern
NH may stay a bit cooler if it stays cloudier/more showery. Onshore
flow and increasing moisture ahead of the next system will bring a
chance of fog and low stratus Monday night into early Tuesday.

Going into Tuesday, skies stay mostly cloudy and cooler as moisture
further increases with an upper low moving across the Great Lakes,
likely bringing the next round of widespread precipitation to the
region. There`s still some timing differences among the models, but
in general most of the precip is expected to be from late Tuesday
morning through the early overnight hours Tuesday night before
conditions start to dry out. It`s also possible eastern areas may
not see much precip during the day on Tuesday. PWATs are
forecast to approach 1.50" which is again around the 90th percentile
for this time of year. This could again allow some pretty efficient
rain rates with lift further aided by being in the right entrance of
an upper jet. While not zero, ensembles currently have 10% or less
for QPF exceeding an inch of rain with this system, which is good
news with all the rain from Friday and today.

Warmer and drier conditions return for Weds-Fri, but the 500mb
pattern still shows broad troughing across eastern Canada extending
down into Northeast. This will probably allow a few weak
waves/fronts to cross through and bring low-end shower chances,
especially Weds-Thurs.

Now for the real question...will we break the streak and finally
have a dry Saturday? It`s too early to tell. Today`s 12Z GFS
latched onto lifting a frontal boundary back north into the
region, which would keep rain in the forecast. There`s more
support within the GFS individual ensembles for this while
there`s more of a signal for dry weather within the ECMWF camp.
However, the incoming 12Z operational ECMWF is now showing a
wave approaching from the north and west. Time will tell, but
for now the forecast carries the NBM PoPs of 20% to 30%.


&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
Short Term...Rain showers taper off with thunderstorms possible
in the vicinity of PWM and PSM late this afternoon. Patchy fog
is expected to develop in the wake of today`s rain which may
bring about IFR/LIFR restrictions to all terminals. Once daytime
mixing begins fog will clear out VFR should be the prevailing
condition for Sunday. Ceilings will begin to thicken and lower
overnight Sunday.

Long Term...A few showers are possible Monday, mainly over southern NH, but
there`s a pretty good signal for MVFR to possibly IFR ceilings for
the first part of Monday across southern NH into PWM. Fog and low
ceilings are looking likely Monday night,and then more flight
restrictions and widespread precip comes Tuesday into Tuesday
night with mostly VFR Weds-Thurs although a few showers are
still possible.

&&

.MARINE...
Short Term...Areas of dense fog will follow in the wake of
today`s rain showers and persist overnight. High pressure will
build over the waters Sunday, leading to tranquil conditions
through Sunday night.

Long Term...In general conditions looks to stay below SCA levels
this week. A couple of weak lows may pass near or across the
waters Mon-Tues and then another Wednesday into Thursday. Low
pressure remains near the Canadian Maritimes through late week,
and then high pressure may build in sometime next weekend.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...Flood Watch until 8 PM EDT this evening for NHZ007-008-011-012-
     015.
MARINE...None.

&&

$$


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