Manchester, New Hampshire 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

096
FXUS61 KGYX 190202
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1002 PM EDT Wed Jun 18 2025

.SYNOPSIS...
Very warm and muggy conditions are expected tomorrow, before a
cold front approaches the region. The cold front will bring
higher chances for showers and thunderstorms, some of which
could be strong to severe. Friday and the weekend will be drier,
with windy conditions likely Friday. A few showers or
thunderstorms cannot be ruled out through the extended weekend.
Hot and humid conditions will then return early next week.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
10pm Update...Forecast temps are on track as well as the fog
forecast. Issued a Dense Fog Adv for the Midcoast through Casco
Bay. Quarter-mile visibility has been in place towards Rockland
for a number of hours, and stratus over southern ME will
continue to build down, expanding the lowered vis. Will start
with just the coast at this hour, but HREF probs indicate the
likely expansion inland as the night progresses. Also adjusted
some PoPs into Thursday morning as believe bulk of shower/storm
activity takes place after noontime.

Previous Discussion...
Scattered showers are occuring over the area, with low- stratus
still over most locations in New Hampshire and western Maine.
Low stratus will build back in tonight, with fog likely to be
much more prevalent than last night. Dense fog is likely along
the Midcoast, and could persist through a decent amount of
tomorrow morning. Fog and low-stratus will likely make tonight
feel very warm and muggy, with lows in the upper 60s expected.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Low-stratus will peel out of most interior locations
tomorrow morning. Clearing skies will allow for destabilization,
especially across southern NH. It will feel hot and humid, with many
places getting into the upper 80s across southern New Hampshire.
In the interior Seacoast, it may even feel like upper 90s in
the afternoon. A Heat Advisory has been issued for eastern
Hillsborough and interior Rockingham counties, though this kind
of heat could even extend out towards Concord and Jaffrey as
well. Heat will be followed by strong thunderstorms in the
evening.

Strong instability and wind shear ahead of a cold front will allow
for the development of discrete supercells tomorrow afternoon. CAPE
of 2000-3000J, steep low-level lapse rates and up to 200m2/2 of
storm relative helicity will create conditions conducive for
damaging winds, large hail and/or potentially a brief tornado. The
SPC has most of NH and western ME in a Slight Risk for severe
weather. Heavy downpours are also possible with storms, but any
flash flooding should be limited in nature due to the storms
progressive nature, despite PWATs of near 1.8" or so.  Storms will
arrive in New Hampshire by around 5pm, northern NH/ME by 6pm, and
storms will expand into western Maine by 8pm. The threat of
severe storms is the lowest over the Midcoast due to the
seabreeze expected over the area.

Showers and storms may linger through tomorrow night, and should
make for another warmer night as well. Lows tomorrow night should
range from the upper 50s up north, to the upper 60s along the
Seacoast.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
The cold front continues to depart to the east on Friday while the
surface low gradually lifts into the Canadian Maritimes. There is a
better consensus among the models in a quicker FROPA and low
departure than at this time yesterday, so there is more confidence
in a drier and breezier day across the region with some showers
still possible in the mountains with upsloping and the upper wave
crossing. With good mixing, forecast soundings from the NAM support
W/WNW wind gusts of 30-40 mph, but the NAM is often too low with
mixing, so the higher end wind gusts could be more in the 40-50 mph
range, which is close to what the GFS forecast soundings advertise
at the top of the mixed layer. So may need to be consider a
Wind Advisory if this trend holds. Temperatures for the most
part will be "cooler" than Thursday with mid 70s to lower
80s...although for some of the coast it may be warmer than
Thursday with winds being offshore this time.

An expansive upper ridge across the Deep South extending well up
into the Great Lakes will gradually build toward New England and the
Eastern Seaboard over the weekend bringing a warming trend. There`s
still uncertainty on chances for showers and storms over the
weekend, although there is arguably a little better agreement in
timing of wave(s) riding into the area on the eastern periphery of
the ridge with the higher PoPs favoring Saturday night and into the
first half of Sunday at this point. However, there is still quite a
bit of uncertainty in the location.

Going into early next week, confidence remains high in the
strong ridge further expanding toward the area and bringing the
hottest temperatures of the year so far, which will also come
with increasing humidity. Monday and Tuesday could both feature
heat indices reaching the mid to upper 90s across portions of
the interior with most precipitation staying north of the
region. There is more uncertainty on whether it will remain as
hot going into next Wednesday with more spread in the guidance
as a front may approach from the north and weaken the ridge.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Short Term...Restrictions will likely stay down through the
rest of the evening, as showers and low stratus continue to sit
over the area. Restrictions will stay down through the first
half of tomorrow, as the aforementioned low-stratus hangs on.
Some clearing may provide a brief return to VFR around noon
tomorrow before thunderstorms move into the area, and bring
sites down through the rest of the afternoon. Showers and some
patchy fog tomorrow night will allow for restrictions no better
than MVFR to exist overnight and into Friday morning.

Long Term...Drier on Friday, but HIE could still a few showers
as well as MVFR ceilings. Otherwise, expecting primarily VFR
with brisk W/WNW of 25 to 35 kt, potentially over 40 kt on the
high end. There will be a chance of showers and storms over the
weekend with guidance favoring Saturday night into Sunday of
having the higher potential. However, confidence is low on
location(s). By early next week. expecting mostly VFR.

&&

.MARINE...
Short Term...Low-stratus will bring poor visibility over the
Gulf of Maine tonight. From this afternoon through Thursday
evening, southerly winds of 9-14kts expected, with 2-4ft seas.
Winds and seas pick up to near SCA levels Thursday evening as a
cold front moves through the area. By Friday morning, winds over
the waters should be out of the southwest, with upto 5ft seas
likely. SCA issuance possible Thursday night.

Long Term...SCA conditions may persist into Friday as west to
southwest winds remain brisk behind the cold front. Conditions
then generally remain below SCA levels over the weekend as high
pressure builds across the waters and then becomes centered
south of the waters. South to southwest flow persists early next
week, and there some indications a front may approach from the
north late Tuesday or Wednesday, which could tighten the
pressure gradient and increase winds across the waters.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Dense Fog Advisory until 8 AM EDT Thursday for MEZ024>028.
NH...Heat Advisory from noon to 7 PM EDT Thursday for NHZ012-013.
MARINE...None.

&&

$$


NEAR TERM...Cornwell/Palmer
SHORT TERM...Palmer
LONG TERM...Combs