Windham, New Hampshire 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

894
FXUS61 KGYX 242301
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
701 PM EDT Fri Jul 24 2026

.WHAT HAS CHANGED...
No significant changes have been made this evening for the
overnight forecast other than to add a little more fog to the
midcoast of ME and the CT valley.

&&

.KEY MESSAGES...
1. Pleasant weather continues through Sunday under high
pressure.

2. Quiet weather comes to an end with unsettled weather
returning for the first half of next week with the potential for
areas of heavy rain.

&&

.DISCUSSION...
KEY MESSAGE 1 DESCRIPTION...

The combination of clear skies, light winds, and low dew points
will allow for another night of radiational cooling tonight.
Forecast lows are mostly based on MOS guidance, with lower to
middle 40s expected across the northern valleys and lower to
middle 50s elsewhere. Valley fog is once again likely,
especially towards dawn as temperatures cool to near their dew
point and a large temperature gradient between air and water
sets up.

Surface high pressure will drift towards the Canadian Maritimes
on Saturday, allowing for light southeasterly flow across the
region. Other than some diurnally driven cu across the foothills
and points north, mainly sunny skies will prevail with high
temperatures into the 80s, although cooler temperatures will be
common along the coast due to the onshore flow. Saturday night
will be on the cool side for late July with lows into the
40s/50s.

Dry conditions will persist on Sunday with partly to mostly
sunny skies and near average high temperatures into the lower
80s. Low temperatures on Sunday night will mainly be into the
50s with partly cloudy skies.

KEY MESSAGE 2 DESCRIPTION...

Early next week, an omega block pattern establishes across the
region as the western ridge amplifies and Atlantic high builds
northward, parking a longwave upper level trough over the East Coast
through at least late week. An upper-level low over Hudson Bay will
deepen the trough, driving a surface low and accompanying cold front
across New England, with a focus in the Tue-Wed timeframe. Model
guidance shows notable spread regarding the surface low. The
GFS/GEFS favors a weaker, more progressive solution further south,
whereas the ECMWF/EPS depicts a stronger (wetter), closed low
further north.

The predominant forecast impact will be increasing shower activity
and thunderstorms from late Monday through mid-week, potentially
lingering into Thursday if the trough slows. Activity will be
enhanced diurnally rather than a continuous washout. Southerly
return flow will advect deeper moisture across the region, elevating
PWATs into the 1.502.00" range alongside dew points in the 60s.
This juicy moisture profile, combined with lowering heights aloft
and steepening mid-level lapse rates, will support modest
instability (mainly in the afternoons) capable of supporting
localized brief downpours. While initial guidance kept the core jet
dynamics displaced to our south, there will be shear and CAPE
overlap ahead of the front supporting storms. Limiting factors
include cloud cover, height falls, and falling 1000500 mb thickness
values, with surface temperatures seasonably cool in the 70s before
weak ridging attempts to push the trough offshore by next weekend.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
Through 18Z Saturday: VFR conditions expected. The exception is
at KLEB and KHIE where valley FG is once again likely,
especially between 09Z-13Z Saturday. RKD may see it as well.
Light and variable flow will prevail through Saturday. No LLWS
is anticipated through the period.

Outlook:

Saturday night-Sunday Night: VFR conditions expected. An
afternoon sea breeze is likely on Sunday with light and variable
winds becoming SSE, especially across coastal TAF sites.

Monday/Monday Night: Mainly VFR conditions expected. Isolated
SHRA may cause brief localized restrictions.

Tuesday-Wednesday: MVFR or worse restrictions likely due to RA
and possible TSRA.

&&

.MARINE...
Winds and seas will remain below SCA criteria through Sunday
night as surface high pressure remains over or east of the Gulf
of Maine.

Outlook: The gradient will remain relaxed with winds and seas safely
below SCA through the first half of the forecast. A low pressure
system is projected to develop south of the area along the east
coast, supporting multiple rounds of widespread rain and the
occasional thunderstorm mainly Tue-Wed. Looking at increasing winds
and seas with potential for SCA conditions. Quieter weather follows
for the later half of the week.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Beach Hazards Statement until 8 PM EDT this evening for
     MEZ023>028.
NH...Beach Hazards Statement until 8 PM EDT this evening for NHZ014.
MARINE...None.

&&

$$

DISCUSSION...Ekster/Jamison/Tubbs
AVIATION...Tubbs
MARINE...