Rochester, New Hampshire 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

603
FXUS61 KGYX 030241
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1041 PM EDT Fri May 2 2025

.SYNOPSIS...
Showers and some thunderstorms are possible this afternoon
along a cold front. This front slows, allowing for a renewed
chance of showers and thunderstorms Saturday. Some of these
thunderstorms may be strong to severe, capable of producing
gusty winds and small hail. The front eventually stalls over
the area continuing unsettled conditions into early next week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
1040 PM Update...Latest radar shows an area of showers with
embedded thunder tracking east across Rockingham County into
York County and will likely move offshore over the next hour or
two. There is another area of showers over the Hudson Valley
that may track across southern NH late tonight. Areas that have
received recent rainfall this evening have had fog develop and
have mainly adjusted fog coverage and PoPs with this update.

855 PM Update...Despite growing CIN over the area a couple of
thunderstorms have been able to maintain themselves over central
and SW New Hampshire as there is a few hundred J/kg of elevated
instability. Have increased PoPs to cover these thunderstorms
and added thunder to the forecast through the next couple of
hours.

Previously...

Breaks in the clouds this afternoon will allow for a
destabilization of the environment over New Hampshire and the
interior. A few thunderstorms are likely to develop this
evening across New Hampshire by 6pm or so. Storms will continue
through the rest of the evening, moving out of the area tonight.
Light southeasterly flow over the waters will help advect low
stratus and fog into Maine this evening, continuing through
tomorrow morning.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Tomorrow morning, skies lift up and any leftover fog starts to
mix out. Late morning clearing should allow for temperatures to
warm sharply through the day, especially away from the coast.
The clearer skies should allow for destabilization. Some forcing
moving in early tomorrow afternoon should help build some some
thunderstorms across New Hampshire. Convection could become
more organized across the south as CAPE, updraft helicity and
mid-level lapse rates become more favorable for strong to
severe thunderstorm development. The Storm Prediction Center
(SPC) has also issued a `Marginal Risk` for Southern New
Hampshire and York County ME, indicating a 5% chance for hail
and/or damaging winds over the aforementioned area. Storms
should move out of the area by sunset.

After the aforementioned convection crosses the region, a low
pressure system to the west may continue to bring more showers
into New England overnight, with showers potentially continuing
through the day on Sunday.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
1040 PM Update...No major changes with the latest NBM guidance.
There will be chances for showers most days next week as a cut-
off low slowly tracks across the Ohio Valley into the
Northeast. The highest chances for widespread soaking rainfall
will occur late Tuesday into Wednesday as the low makes its
closest pass to New England.

Previously...

Pattern Overview: A 500 mb low will be slowly meandering
eastward from the Ohio Valley through our area, departing mid-
week. This along with a series of fronts, keeps clouds and
showers in the forecast. There is some uncertainty toward the
end of the week as the Euro suite shows another 500 mb low
swinging in right behind the departing one, but the GFS shows
nicer weather returning.

Impacts and Key Messages:
* No significant weather impacts expected.
* The area will see beneficial rain as low pressure brings
  rounds of showers through the weekend and at least the first
  part next week.

Details: Sunday: A wave of low pressure rides along a stalled
frontal boundary draped across the area Sunday. The latest hi-
res model suite is still uncertain on just how far south the
boundary makes it before stalling, with the NAM Nest continuing
to be the outlier that isolates showers to the coast. The tail
end of the HRRR and the RRFS are in the camp of the boundary not
making it much past the mountains. Will go with a consensus
approach, keeping at least a chance of showers across the area,
with more likely probablilites south of the mountains. Global
models remain in good agreement that high pressure building into
the area overnight Sunday pushes the front along, but it may
not clear the coast until early Monday. These showers look light
with some embedded heavier showers, but generally areas could
see another 0.25-0.50 inches with Sundays shower activity.

Monday and Tuesday: As mentioned above, light showers may
linger across southern New Hampshire into Monday morning as high
pressure continues to push a frontal boundary out of the area.
Ultimately, this brief nose of high pressure looks to keep
Monday mostly dry, but our proximity to the meandering 500 mb
low likely keeps skies mostly cloudy across much of the area.
High temperatures may not make it out of the 50s with the
increased cloud cover, and as such low temperatures only bottom
out in the 40s. As high pressure slides eastward overnight
Monday and the first part of Tuesday, this will allow the
vertically stacked low pressure to begin moving toward our area.
There are some subtle differences in timing, but the trend has
seemed to hold steady with the more widespread showers holding
off till later on Tuesday. Skies remain cloudy through the day
so high and low temperatures remain very similar to Monday.

Wednesday-Friday: Low pressure moves overhead Wednesday, so
widespread showers look to continue into at least the first part
of the morning. How quickly showers exit is a point of
uncertainty in the model suites, but that is unsurprising at
this time range. Thursday and Friday are also a big question
mark as the Euro brings another upper level low into the area
right behind the one departing, and the GFS builds high pressure
in. For now the NBM probabilities seem reasonable with a chance
of showers through the day Thursday, then decreasing heading
into Friday.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Short Term...Lowered restrictions are expected this afternoon as
showers and low stratus move through the area. These restrictions
will continue overnight as areas of fog build across New Hampshire
and Maine, bringing periods of IFR overnight. Some improvement is
possible across southern NH tomorrow morning as fog mixes out,
but restrictions lower tomorrow afternoon as storms develop and
move across the New Hampshire and Maine. Showery weather may
still keep restrictions lower through Sunday morning.

Long Term...Sunday will likely feature a mix of restrictions as
shower coverage diminishes through the day. Some improvement
may be seen Monday, but widespread MVFR ceilings are likely
through Tuesday. Tuesday night is when conditions go back
downhill again with a mix of restrictions likely as widespread
showers return. Improvement is expected again on Wedensday, but
the timing is more uncertain. Generally winds look light with
gusts less than 15kts.

&&

.MARINE...
Short Term...Winds and seas are expected to remain below SCA
criteria through Sunday morning. Winds will be out of the south,
with seas remaining below 5ft through Sunday. However, some
storms Saturday evening may bring some gusty winds over the
waters.

Long Term...Wind gusts and wave heights are below SCA criteria
in this forecast period as high pressure slides over the waters
on Monday. Winds are generally northeasterly through Monday with
a brief wind shift as a front moves over the waters on Sunday.
As high pressure moves over the waters Monday evening winds will
shift around more onshore through Wednesday.

&&

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

&&

$$


NEAR TERM...Palmer/Schroeter
SHORT TERM...Palmer
LONG TERM...Baron/Schroeter