Severe Thunderstorm Warning 22, NWS Gray, ME

Area Forecast Discussion
National Weather Service Gray ME
251 PM EDT Fri Jun 26 2026

.WHAT HAS CHANGED...
A Severe Thunderstorm Watch is in effect through 9pm this
evening for most of New Hampshire and York County, Maine. Heat
looks increasingly likely for midweek next week.

&&

.KEY MESSAGES...
1. Chances for showers and thunderstorms increase this
afternoon. Some storms could be strong to severe with damaging
winds and hail as the primary hazards. A Severe Thunderstorm
Watch has been issued for Central and Southern New Hampshire and
far southwest Maine. Fog could then be dense in some areas
tonight.

2. A trough exits New England Sunday through Monday.

3. A substantial warming trend follows through the remainder of
the week next week as a ridge builds across the eastern half of
the US. The potential for hazardous heat is increasing for mid
to late week next week.

&&

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

Earlier rains have shifted off to the east as broad low pressure
approaches from the west this afternoon. Increasing lift and
instability will allow additional showers and thunderstorms to form
this afternoon, and this is already underway just upstream
across upstate NY and approaching VT.

Diving in a little deeper, latest SPC Mesoanalysis depicts
roughly 1000 J/kg of SBCAPE and 40-50 kt of effect shear across
much of NH and portions of far western ME, that will be
sufficient to support some of these storms becoming strong to
severe as the develop or move into the area. Damaging winds and
hail 1" or larger in diameter will be the primary hazards, but a
brief tornado or two can't be completely ruled out. A Marginal
Risk (Level 1/5) from the SPC continues for all of NH and into
portions of western ME, but within this Marginal Risk area, the
higher risk appears to be roughly along the CT River Valley
extending into central and southern NH and far southwestern ME
where the better overlap in shear/instability is forecast to be
SPC recently upgraded this higher risk area to a Slight Risk
level 2/5, which is also where a Severe Thunderstorm Watch has
been issued until 9PM this evening.

Another potential hazard is the risk for flash flooding within
slow-moving persistent showers/storms or where multiple rounds
occur. One area to watch in particular is in and around the NH
Lakes Region, where 1-2" of rain already fell overnight and this
morning around Lake Winnipesaukee.

Showers and storms will lessen in coverage and intensity toward
sunset, but the HRRR suggests a couple of showers or storms may for
an hour or two after. Other than a few upslope showers in the
mountains overnight, the rest of the area is expected to remain dry.
With light winds and saturated grounds from today's rain, most of
the area has fog in the forecast. Fog could be dense in some areas
with the higher probabilities of this occurring in western ME.

Drier conditions are forecast for Saturday with light winds and
seasonable temperatures in the 70s to lower 80s. Aloft, weak
troughing will still be overhead, so as daytime instability builds
scattered showers and isolated storms will develop from late morning
and through the afternoon hours before waning toward sunset. A
couple of storms could produce small hail. There are also
indications of slower-moving storms and heavy downpours, so the next
shift may to take another look at potential hydro issues.

Light winds Saturday night will again promote patchy fog, especially
in valley and areas that receive rain during the day. Overnight
temps will be in the 50s.

KEY MESSAGE 2 DESCRIPTION...

The influence of the lingering trough will still be felt on
Sunday with increased chances for pop up showers and storms
during the afternoon hours. The best chance for these will be
across the higher terrain and central Maine, with generally
lower chances toward western New Hampshire. Temperatures also
begin to rebound with relatively more sunshine on Sunday.
Central and southern New Hampshire likely warm into the low to
mid 80s, with mainly 70s expected elsewhere.

By Monday, chances for showers drop off significantly as the
trough exists to the east, and the warm up begins. Highs are
expected to warm into the 80s across most of the region, with a
sea breeze knocking back temps along the coast by the afternoon
hours.

KEY MESSAGE 3 DESCRIPTION...

The main warm up then gets underway by Tuesday as a highly
amplified ridge builds across the Midwest and Great Lakes. New
England looks to be positioned on the eastern portion of this
ridge, but the trend since yesterday has been for the ridge to
set up a little further east. This progression has been
supported by the full suite of the Euro, Euro Ensembles, and
AIFS models. The GFS has been a cool outlier, but looks to be
following the way of the Euro on it's latest run. We'll continue
to monitor for any changes in trends over the next few runs.

This pattern supports at least a couple days of widespread
highs in the 90s, and potentially more days should the ridge
remain amplified enough to ward any backdoor fronts or
retrograding trough from the Canadian Maritimes. Tuesday looks
like the potential first day of 90s reaching into southern New
Hampshire. Wednesday and Thursday then bring the potential for
the most widespread heat with highs into the 90s across much of
the area. This heat also brings with it some deep moisture
originating from the Gulf of Mexico, and transiting through the
Midwest and Great Lakes. This brings dew points into the upper
60s and 70s, combining with highs in the 90s to bring heat
indices potentially into the triple digits.

This pattern progression is a reversal from the trends seen
yesterday, but appears substantial and consistent enough across
most of the model suites to be believed. This weekend would be
a good time to get any air conditioners and fans set up before
the most substantial heat and humidity of the year arrives.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
Through Saturday...RKD may stay LIFR to IFR this afternoon with
MVFR to VFR cigs elsewhere. Showers and storms could also
produce MVFR to IFR restrictions along with gusty winds,
especially for the southern NH terminals and maybe PWM. For
tonight, IFR to LIFR from fog and low stratus will be likely
over much of western ME, but fog and low stratus may bring IFR
elsewhere overnight.

Improvement to VFR is expected Saturday morning, which will
prevail most of the day. TEMPO MVFR possible from scattered SHRA
and isolated TSRA in the afternoon.

Outlook:

Saturday night: Mainly VFR. IFR/LIFR possible from valley fog at
HIE, LEB, and CON.

Sunday: Mainly VFR, but brief restrictions in showers and
storms possible across northern and eastern terminals.

Sunday Night - Tuesday: Mainly VFR, but nighttime valley fog
possible.

Tuesday night - Thursday: Mainly VFR, but rounds of showers and
storms possible at times.

&&

.MARINE...
Through Saturday night...Conditions will remain below SCA
levels through Saturday night. Southerly flow continues into
this evening as low pressure approaches from the west. This low
will bring an ongoing chance of rain showers into this evening
along with the possibility of offshore-moving thunderstorms,
especially from around Casco Bay southward. Winds briefly turn
light and north to northwest tonight and then will be more light
and variable in direction Saturday and Saturday night.

Extended...Generally fair conditions are expected as broad high
pressure gradually build across the waters early to midweek
next week.

&&

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

&&

DISCUSSION...Combs/Clair

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