940
FXUS61 KGYX 031753
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
153 PM EDT Thu Jul 3 2025

.SYNOPSIS...
An approaching cold front will continue to bring the threat of
a few strong to severe thunderstorms through early this
evening. Once the front passes this evening and tonight, a much
cooler and drier air mass settles in for Independence Day, with
temperatures in the 70s and 80s and comfortable relative
humidities. The weekend will gradually get warmer and more humid
with shower chances mainly confined to the mountains on Sunday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Initial round of showers and thunderstorms currently moving
eastward across western ME associated with a lead short
wave/vort max will continue to bring the potential of an
additional strong to severe storm or two, but recent radar
trends suggest this threat has diminished somewhat. Still,
damaging wind gusts remain the primary hazard of concern, but
hail in excess of 1" in diameter is also possible, especially
within any discrete cells.

Looking upstream to the west, visible satellite imagery
indicates clearing across VT and working its way into NH,
potentially giving the atmosphere a chance, although somewhat
brief, to recover and get back instability as additional
forcing from the cold front approaches. This will bring another
opportunity of strong to severe thunderstorms through the
remainder of the afternoon into early evening, although there is
uncertainty in the coverage. The Severe Thunderstorm Watch will
continue through 6PM across all of New Hampshire and western
Maine for both of these rounds.

Showers and thunderstorms are expected to quickly die off this
evening with most CAMS suggesting 6 to 8PM for most of the
activity aside from a few lingering cells. This will be followed
by a period of a few upslope showers in the mountains while the
northwest winds behind the front bring drier and clearing skies
overnight for the rest of the area. Low-level flow will remain
very light, so it`s possible fog develops in some areas,
especially for those that receive rainfall today.

&&

.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
Post-frontal cooler and drier air settles in for Independence Day
with northwest flow in place. Highs will range from the mid 70s to
low 80s south of the mountains to the upper 60s to lower 70s in the
mountains, and good mixing with drier air aloft will bring dewpoints
down into the high 40s to lower 50s, making for comfortable
humidity. The upper low that sends the cold front through later
today will still be lurking toward north of the area to start the
day, but it`s expect to dive to the south and east toward the
eastern half of Maine later in the day. As it does so, enough lift
will bring a chance of showers mostly across northern areas, and
temperatures will aloft will steadily cool underneath the upper low,
so can`t completely discount a few storms either across the western
ME mountains. The rest of the area is expected to be mostly to
partly sunny and dry with somewhat breezy conditions of 20 to 30
mph.

Winds diminish Friday evening, and with light winds and mostly
clear skies, temperatures should cool off fairly quickly with
most being in the 60s for evening outdoor activities. It will be
seasonably cool for the overnight with lows mostly in the 50s
and even upper 40s in some of the northern valleys and normally
cooler spots.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Key Messages:
* Temperatures will be above normal through the period...with some
  potential for heat advisory thresholds to be reached across
  southern New Hampshire on Monday depending on cloud
  cover/precipitation potential

* Machine learning guidance suggests Monday with the best potential
  for severe thunderstorms...with some weak signals beyond this.
  However...confidence is low on this given uncertainty with
  potential TC development off the southeast coast...and this
  system/s potential to slow the frontal progression into our area
  early next week.

Details:

Saturday-Sunday: Northwest flow aloft back westerly through the
weekend as H5 ridge moves into the region.  T8s warm substantially
/+6C/ from Saturday afternoon through Sunday with return flow
pushing dewpoints from the lower 50s Saturday into the 60s on
Sunday.  While a few of the deterministic runs show convection
attempting to make it over the ridge late Saturday...the overall
ensemble signal keeps precipitation north of the area with mid/upper
level cloudiness the more likely result.

Monday-Tuesday: Shortwave trough moves into the region during this
period with some potential for a frontal passage with
shower/thunderstorm chances.  There are conflicting signals on the
timing of this front...as potential TC activity off the southeast
coast acts to build the downstream ridge and slow the overall
progression of the front. Given increasing moisture south of the
front...heat headlines may be necessary for southern areas during
this period contingent on either 1) clouds/storm activity ahead of
the front and/or 2) shower activity lifting north and east ahead of
the potential tropical system off the SE coast.

Wednesday-Thursday: Ensembles paint a quieter picture to end the
long term with weak high pressure building into the area behind the
early week cold front.  Somewhat drier and cooler air is
expected...though temperatures are still expected to remain above
normal through the end of the forecast.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
Short Term...Showers and storms, some potentially strong to severe, will
remain capable of producing TEMPO IFR conditions into early this
evening as well as hail and gusts on the order of 40 to 50 kt should
any pass over a terminal. Outside of SHRA/TSRA, VFR is expected.
Once convection dies off this evening, mainly VFR tonight, although
can`t rule out fog developing, especially in valleys. VFR expected
Friday into Friday night.

Long Term...VFR conditions are expected to persist through the
weekend /outside of some potential for morning haze/...with an
increasing potential for shower/thunderstorm activity on Monday
with the approach of a cold front. This will increase the
potential for restrictions.

&&

.MARINE...
Short Term...SCA conditions are not expected through Friday night. A cold
front approaches this afternoon and crosses this evening with S/SSW
becoming westerly into tonight. It will also bring the potential for
showers and thunderstorms through early this evening, which will be
capable of producing strong wind gusts and small hail. Winds remain
out of the west to northwest Friday into Friday night as weak low
pressure remains centered near the Canadian Maritimes.


Long Term...Residual waves near 5 feet are expected over the
outer waters as we open the period Saturday with decreasing
winds/waves resulting in headline-free conditions by late
morning Saturday through Monday. By Monday...increasing moisture
will result in the potential for fog over the waters.

&&

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

&&

$$


NEAR TERM...Combs
SHORT TERM...Combs
LONG TERM...Arnott