Nashua, New Hampshire 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

297
FXUS61 KGYX 100922
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
522 AM EDT Thu Jul 10 2025

.SYNOPSIS...
Scattered showers will continue today as a frontal
boundary waffles just south of the area, before clearing out by
Friday. The Bermuda high will be in place through the weekend,
supplying mostly dry and warm weather. The ridge breaks down
for the start of the new work week, with a return of hit and
miss showers and warming temperatures.

&&

.NEAR TERM /THROUGH TODAY/...
520 AM Update...Mostly made adjustments to PoP as showers on the
northern edge of and MCV continue to stream into the southern
New Hampshire and southwestern Maine. Overnight these showers
were light and generally remain light with more isolated
moderate rates just now starting to be reported by gauges in
southwestern New Hampshire. This will have to continue to be
monitored through the early morning, before attention turns to
expected convection this afternoon.

Previous Discussion...
Northwestern portions of the forecast area continue to hold onto
some meager MUCAPE...but it is sustaining isolated convection at
times. There is not much in the way of organized forcing...so I
will keep slight chance to chance PoP going thru most of the
night.

Otherwise there will be some threat for fog to move inland
tonight. It is currently masked by higher clouds on
satellite...but the peeks I am able to see show it moving
westward across the Gulf of ME. Hi-res guidance suggests this
will arrive at the local coastline between midnight and 2 AM. I
have used the latest HRRR for timing...but left things at
visibility higher than dense fog criteria given the uncertainty.

As we near sunrise the synoptic situation changes. A S/WV trof
will pivot into the St. Lawrence River Valley and the upper jet
will begin to strengthen. The forecast area will be in the right
entrance region of that jet streak...and the resulting forcing
for ascent will support more widespread coverage in convection
by morning. Heading into the afternoon...diurnal heating will
lead to greater instability and more robust convection. While
the strongest storms should remain west of the forecast area
based on latest ensemble and machine learning guidance...the
PWAT values will remain elevated and torrential rainfall will be
possible with any shower or storm. Once again we will have to
keep a close eye on training storms for any flooding potential.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY/...
Impacts and Key Messages:
* No significant weather impacts expected.

Tonight: Shower and thunderstorm coverage will diminish as we
head into the evening, but broad upper level troughing overhead
will continue to provide some forcing and support some isolated
showers through the overnight period. I would imagine these
would be mainly in and around the terrain where orographic lift
would provide additional forcing. Otherwise, a cool night is
expected with temperatures dropping into the upper 50s and low
60s.

Friday: Friday looks mostly dry as the frontal boundary that
has hung around all week, finally retreats well south of New
England. The upper trough axis will cross the area during the
day which may again aid in the development of some mountain
showers and/or storms. Ridging will begin to build in during the
afternoon and generally we should see clearing skies and the
beginning of a warming trend with high temperatures climbing
into the upper 70s and low 80s.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Evening update...No significant changes to the long term
forecast with inclusion of the latest NBM. Deep layer ridging
should keep the first part of the weekend mostly dry. Then our
summer pattern will return in full swing with chances for
afternoon showers and thunderstorms each day next week. We will
also see a trend toward above normal temperatures heading into
the middle of next week.

Previous Discussion...
Key Takeaway:Typical summertime pattern expected over the long term.
High pressure builds in over the weekend, followed up by a series of
weak upper level systems that will push across the area bringing
unsettled hit/miss weather through the rest of the work-week. Hit or
miss showers possible, but no widespread rainmakers or otherwise
significant weather anticipated at this time.

The 500 mb ridge and the subsequent surface
high builds in further on Saturday and into Sunday likely bringing
warm and dry conditions. Light flow could support sea fog
development and will need to watch for any coastal impacts both
Saturday and Sunday mornings. Into the latter parts of Sunday and
beyond, the ridge breaks down with a more zonal flow developing.
Subtle shortwaves in the 500 mb flow regime combined with typical
summer-like moisture and diurnal instability could allow for more
showers and thunderstorms to develop early next week. However,
because of the subtleness of these features and our temporal
proximity to the event, confidence is low at the timing of each
wave. There is also a signal for the middle of next week for
anomalously warm and humid conditions as another 500 mb ridge builds
back into the region so will have to keep an eye on that as
well.

&&

.AVIATION /09Z THURSDAY THROUGH MONDAY/...
Short Term...Any fog and low ceilings should improve slightly
to at least MVFR by late morning. MVFR is expected to prevail
through much of today with maybe some of the more northern
terminals able to pop into VFR for a bit in the afternoon.
Abundant low level moisture, especially in areas where it
rains/storms today, will see low ceilings and or fog develop
again tonight bringing most terminals down to at least IFR
overnight. Friday should see more VFR as mid levels dry out and
skies clear. HIE may see some brief showers/storms Friday
afternoon.

Long Term...Quiet weather into Sunday, with only an isolated
threat of showers with reduced flight cats. Late night and early
morning fog and stratus in the valleys and sea coast will also
be possible.

&&

.MARINE...
Short Term...Wind gusts and seas remain below SCA criteria
through Friday as the waters remain on the periphery of high
pressure. Areas of fog are likely through at least tonight. A
few thunderstorms may move over the waters this afternoon.


Long Term...Expect similar to above through the weekend and much of
the work week. There will be a slight downward trend in the winds
over the weekend with the surface high overhead. Waves primary SSE
swells and winds for the majority of the forecast, with no
significant periods above 8 seconds expected.

&&

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

&&

$$

NEAR TERM...Baron/Legro
SHORT TERM...Baron/Legro
LONG TERM...Baron/Venarsky