171
FXUS61 KGYX 041045
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
645 AM EDT Fri Jul 4 2025

.SYNOPSIS...
A much cooler and drier air mass settles in for Independence
Day. Temperatures in the 70s and 80s and comfortable relative
humidities are forecast. The weekend will gradually get warmer
and more humid with shower chances mainly confined to the
mountains on Sunday. Hot temperatures make a return late this
weekend into early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
645 AM Update... Other than loading in the latest surface
temperatures and smoothing trends, no changes were made to the
forecast at this time.

Previously...
A pleasant day ahead as a drier airmass brings a relief from
recent humid conditions. Temperatures top out in the mid to
upper 80s across southern NH into the coastal plain of ME and
the lower Kennebec Valley. It may feel a few degrees cooler with
a northwest wind gusting 20 to 25 mph at times.

There will be a shallow moist layer in the low levels that
produces scattered to broken ceilings late this morning through
the afternoon. Near overcast skies will be possible towards the
US/CAN border as some of this moisture gets trapped by terrain.
Also can`t rule out some passing showers in the mountains of
western ME as this moisture combined with cooler air aloft
deepens clouds.

Those adventuring the higher summits today should be aware that
stronger winds and cooler temperatures are likely with
elevation, and there can be a great contrast from trail-head to
peak. Wind chill values in the Presidentials are forecast to
spend much of today and tonight at or around freezing. Pack
accordingly, and know your limits. In other recreation
awareness, today`s NW winds will create good fetch across larger
inland lakes. For Winnipesaukee and Sebago, this could mean
wave heights of 2 to 4 ft at parts of the lake.

Winds will subside late this afternoon and evening, along with a
thinning of daytime clouds.

&&

.SHORT TERM /SATURDAY/...
Shower activity pushes east by this evening, with winds
subsiding and skies clearing for the most part. Kept with the
day crew`s thinking on a cool night for the Whites and foothills
with good radiational cooling once conditions settle. This could
bring lows into the 40s, with low to mid 50s elsewhere for the
night.

Temperatures begin a warming trend Saturday and for the rest of
the weekend. Values will climb into the 80s and upper 70s for
much of the area as winds shift SW. Not as breezy with
increasing clouds, topping out around 15 mph.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Long Term Update: Not much change to going forecast thinking in
the long term. Of note is the continued hot temperatures
forecast for Sunday and Monday. Have included mention in the HWO
that heat indices will be at or near 95 for a portion of
southern NH and interior southern ME both/either day. NBM IQR
continues to tighten on both of these days, increasing
confidence. There remains uncertainty for precip timing and
coverage Monday as the main boundary fcst remains draped along
or just north of the US/CAN border.


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 Night-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 into the 60s on Sunday.

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 /12Z FRIDAY THROUGH TUESDAY/...
Short Term...Valley fog develops overnight, and retreats after
sunrise. MVFR ceilings may be present for a portion of the day
for terminals in the western ME mountains and northern NH. A
trend towards VFR is expected later this afternoon and
overnight. NW winds increase this morning, with gusts to 25 kt. VFR
Saturday, less gusty.

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...Conditions below SCA as NW winds increase during
the daytime. Winds slacken this evening, becoming SW for
Saturday. This will allow slow build of wave heights through
Sunday.


Long Term...Wave heights may build to 4 to 5 ft Sunday evening. 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...Tubbs
SHORT TERM...Cornwell
LONG TERM...Arnott/Cornwell