060
FXUS61 KGYX 171925
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
325 PM EDT Tue Jun 17 2025

.SYNOPSIS...
Isolated showers are expected this afternoon, with low-stratus
building in across NH and ME tonight. Warmer temperatures are
expected along with a chance of late afternoon showers and
thunderstorms north of the mountains on Wednesday. A cold front
approaches on Thursday with higher chances for showers and
thunderstorms. Friday and the weekend will be drier but a few
showers or thunderstorms cannot be ruled out.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Current radar and satellite imagery shows a few isolated
showers moving northeastward across NH and western Maine. A few more
showers are expected to move in this evening and will continue
overnight. Tonight, onshore flow will allow for low marine
stratus and fog to advect into the area, likely overspreading
most regions south of the mountains. The stratus should also
allow for warmer lows, with low temperatures tonight expected in
the upper 50s and lower 60s.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Tomorrow will feature a relatively zonal 500mb pattern, with a
small ridge building through the day. Some low stratus looks to
linger over the coastal plain, with clearer skies and more
mixing likely in the mountains. Low-stratus should mix out
across most areas in the late morning, though overcast skies
are expected to remain through the rest of the day.

Mixing and destabilization up north may allow for a couple isolated
thunderstorms to develop along a weak frontal boundary that will
move in from Quebec tomorrow afternoon. The boundary should fall
apart as it crosses the international border, with the storm threat
tomorrow mainly only in play for outdoor recreators in areas
such as Pittsburg, Rangeley, and Jackman. If storms develop,
they will likely be sub-severe.

Opted to cool the Midcoast`s high temperatures tomorrow, as low-
stratus is expected to be the most dense and persistant. Highs
in the upper-60s are expected there, with highs in the upper 70s
most elsewhere.

Tomorrow night, calm winds and onshore flow should allow for marine
low stratus to make a return over the area. Low stratus should also
allow for lows to stay on the warmer side, with many places only
bottoming out in the mid to upper-60s. The warmer lows and high humidity
should allow for a muggy morning on Thursday.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
An area of low pressure will move roughly along the St. Lawrence
River Valley on Thursday and drag a cold front toward New England
later in the day. Well out ahead of the front, moist onshore flow
will bring a cloudy start to much of the region with low stratus and
fog. The expectation is then for a decrease in clouds from west
to east as the morning goes on and into the afternoon with
temperatures climbing into the 80s across much of the interior
and even low 90s possible across southern NH and into SW ME.
With dewpoints in the forecast to be in the mid to upper 60s,
portions of southern NH may see heat indices in the mid 90s for
a couple of hours.

As the front approaches, chances for showers and storms will
increase in the afternoon and evening, and instability/shear
profiles do suggest an environment to where a few storms could be
strong to severe. There is still some uncertainty in the timing of
the front, so if it`s slower to enter the area (closer to sunset),
the threat for strong to severe storms will be lower. Still, the
risk is highest across NH and the western ME mountains and even
moreso along the CT River Valley where SPC has placed a Slight Risk
(Level 2/5) with a Marginal Risk extending eastward into all of
western ME (level 1/5). That said, I do think the threat will be
lower south of the I-95 corridor where the seabreeze/marine layer
will add more stability. We`re looking at damaging wind gusts and
hail as the primary hazards, but another potential hazard is locally
heavy rainfall and isolated flash flooding. Very efficient rain
rates are possible given PWATs are forecast to climb into the 1.6-
1.8 inch range with warm clouds depths 11-12kft. Potential for
storms will wane as the evening and overnight go on, but showers
remain possible with the 500mb shortwave still yet to cross
through.

Friday is a little less certain with some guidance showing a quicker
frontal passage while others suggest a slower passage with perhaps
another weak low developing along it. The faster solution would
result in a drier/breezier day on Friday while the slower solution
keeping more clouds/showers a little longer. However, even with the
slower solution, it could still get pretty breezy across western
areas.

For the weekend, a strong 500mb ridge builds across the Deep South
and toward the Great Lakes, which will gradually expand toward the
East Coast. New England will be on the eastern periphery of this
ridge with a couple of disturbances possibly riding along it to
bring an opportunity or two for showers and storms over the weekend,
although confidence in timing and location remains lower.
Temperatures remain warm across much of the interior with temps well
into the 80s possible by Sunday.

Of higher confidence is the heat and humidity set for early next
week with strong ensemble support for anamalously warm temperatures
aloft as the ridge further expands. The combination of hot
temperatures  and humidity could produce heat index values in the
mid to upper 90s.


&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
Short Term...MVFR visibility and CIGS are currently being
reported across NH and western ME. Restrictions will continue to
deteriorate this evening, as showers and low stratus move in.
Restrictions stay down overnight and through most of the day
tomorrow, as showers move out but low-stratus and patchy fog
hangs on in most places. There may be a brief window at some TAF
sites tomorrow afternoon, where sites return to MVFR, but low-
stratus will backbuild later on tomorrow evening, bring most
sites back down again.

Long Term...There is pretty high confidence for IFR to LIFR
conditions at most terminals with low stratus and fog present
Thursday morning. Improvement is expected into the afternoon
with NH terminals more likely to see VFR conditions while the ME
sites may hang on to some degree of restrictions. A cold front
then approaches in the afternoon and evening, bringing a chance
of showers and thunderstorms, which will be capable of TEMPO IFR
restrictions. Additional showers are possible behind the front
Thursday night and Friday with the potential for breezy
conditions. Another disturbance could bring an additional chance
for showers and storms over the weekend, but timing and location
is of low confidence.

&&

.MARINE...
Short Term...Persistant low-stratus is expected over the Gulf
of Maine through Thursday morning. Southerly winds at 9-13kts,
with seas of 2-4ft are expected through the period. SCA issuance
not expected.

Long Term...SCA conditions are possible Thursday as southerly flow
increases ahead of a cold front, and these conditions may last into
a part of Friday behind the front. Until the front passes, fog may
continue over the waters. High pressure builds in south of the
waters over the weekend with another weak low pressure/front
possibly moving through at some point. However, timing and location
is uncertain, but it looks like conditions will stay below SCA
levels over the weekend. For early next week, broad high pressure
becomes established over the eastern CONUS and into western Atlantic
with south to southwest flow over the waters.

&&

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

&&

$$

NEAR/SHORT TERM...Palmer
LONG TERM...Combs