Nashua, New Hampshire 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

437
FXUS61 KGYX 071807
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
207 PM EDT Thu Aug 7 2025

.SYNOPSIS...
High pressure will remain over New England through the
remainder of the week with temperatures near seasonable
averages. Increasing heat and humidity and continued dry weather
is then expected this weekend through the middle of next week.
Our next best chance of more widespread showers/storms comes
with a frontal passage mid- to late next week. Smoke and haze
may try to return Friday as winds become southwesterly.

&&

.NEAR TERM /THROUGH TONIGHT/...
Much like the last couple of afternoons...isolated showers or
storms are expected across parts of northern and western NH.
Forcing today looks best across the White Mtns...with less
emphasis down into the Monadnock region. Any slow moving storm
will be capable of 2 to 3 inch rainfall rates...so a quick inch
or two is not out of the question but will be highly localized.

Tonight it will be another seasonable night but feel cool
compared to our recent humid stretch and what is upcoming next
week. Patchy valley fog is once again possible...but less
widespread since we remain in a very dry stretch of weather.

&&

.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
Not much change in the forecast for Fri except that
showers/storms may be a little more focused in the GYX forecast
area. They will still be quite isolated in nature...but the best
chance looks to be in the White Mtns into western ME mtns. Again
the slow moving nature of the convection could result in high
rainfall rates and localized amounts approaching 2.5 inches.
Will also have to keep an eye on lingering smoke layer. It is
currently centered around Lake Ontario...but some models do show
near-surface smoke trying to drift back into areas north of the
notches on Fri. For now I do not have smoke/haze in the
forecast...but it may be needed if we start to see air quality
sensors creeping back up into unhealthy ranges. Fri night will
see similar radiational cooling and potential for patchy valley
fog.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Pattern Overview: Deep layer ridging through much of the much
of the long term forecast period will allow for heat and
humidity to build through the middle of next week. Next best
chance for showers/storms looks to be late Wednesday with
surface frontal passage and approaching 500 mb shortwave.

Impacts and Key Messages:
* Confidence is increasing in a multi-day stretch of
  temperatures around or exceeding 90 degrees beginning Sunday
  into the middle of next week. Heat indices in some locations
  may approach 95F.
* The extended forecast continues to have little in the way of
  precipitation. Expansion of abnormally dry conditions in the
  region is noted with the latest update to the drought monitor.

Details: Saturday: A shortwave trough starts overhead Saturday,
then slides offshore later in the day. This should help the
formation of diurnally driven clouds and showers/storms. With a
lack of any large scale synoptic forcing at the surface, these
will likely be confined to the terrain that will be providing
the lift. Locations south of the mountains can expect clearer
skies and drier weather. The warming trend continues with high
temperatures south of the mountains climbing into the mid to
upper 80s, with the coastal plain staying cooler (in the upper
70s and low 80s) due to a seabreeze. Upper 70s and low 80s can
be expected north of the mountains as well owing to the cloudier
skies. Increasing dewpoints will have low temperatures trending
warmer as well, with upper 50s and low 60s expected areawide
Saturday night accompanied by some patchy fog.

Sunday and Monday: Deep layer ridging begins to build into the
region Sunday, but the shortwave trough phases with low pressure
offshore. This keeps flow northwesterly, so terrain induced
cloudiness will continue and with a bit of an increase, these
may propagate down stream as well making for partly cloudy skies
across most of the area. Still, temperatures should be able to
climb into the mid to upper 80s areawide, with southern New
Hampshire having the best chance of ending up around 90. Surface
southwesterly flow continues to drive up dewpoints and thusly
low temperatures only bottom out in the low to mid 60s Sunday
night. The ridge builds overhead Monday with temperatures
climbing into the upper 80s and low 90s. The humidity becomes
more apparent as continued southwesterly flow may have dewpoints
into the low to mid 60s at this point. Therefore, low
temperatures follow this trend as well ending up in the low to
mid 60s Monday night.

Tuesday-Thursday: The GFS has come around to the Euro with both
models now suggesting ridging stays in place through Wednesday.
Tuesday remains the warmest day with nearly 90 degree
temperatures across the area, but Wednesday may be the most
humid as southwesterly flow would continue. With this being
said, that staves off a frontal passage until late on Wednesday.
This remains our best chance for any kind of more widespread
appreciable rainfall, so this will continue to be watched
closely. Temperatures on Thursday will depend on the progress of
that front, with model solutions differing at this time period.
The Euro and Canadian suite are all for sweeping a front
through, but the GFS wants to hold on to the ridge and heat.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
Short Term...Widespread VFR conditions expected thru Fri night.
Patchy valley fog may result in localized IFR or lower
conditions at LEB especially and maybe HIE. The dry stretch of
weather is making it harder to sustain the fog for longer
periods of time however. Along the coast Fri sea breezes will
once again turn winds southeasterly by midday for
PSM/PWM/RKD...and eventually AUG by afternoon.

Long Term...Other than overnight/early morning fog, VFR will be
the prevailing condition through Tuesday as high pressure
remains over the region. Isolated thunderstorms are possible in
the mountains Saturday afternoon and evening.

&&

.MARINE...
Short Term...Sea breezes expected once again Fri. Winds and seas
will remain below SCA thresholds.

Long Term...Wind gusts and seas remain below SCA criteria
through Tuesday. It now looks like low pressure will pass well
east of the area Sunday night which should keep near shore
waters under 5 ft. Winds will be generally southerly through
Tuesday.

&&

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

&&

$$

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