215
FXUS61 KGYX 302221
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
621 PM EDT Wed Jul 30 2025

.SYNOPSIS...
One more day with hot and humid conditions ahead of an advancing
cold front that will slowly push south across the region
this evening. The slow moving front will stall across southern
counties, continuing rain chances through Friday morning. Dry
weather with comfortable temperatures and humidity levels will
then follow this weekend, lasting into early next week.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
620 PM Update...Thunderstorms continue to remain few and far
between, probably the result of very poor lapse rates aloft and
limited forcing for ascent. We can`t rule out a strong to
locally severe storm for the next 2 hours or so but chances will
be waning.

Previously...

Modest destabilization is underway across the forecast area
with convection blossoming across southern Quebec and northern
Maine ahead of a cold front. As the front sags south through
this evening storms will start moving ESE across northern zones
over the next couple of hours and towards the coast of Maine by
around 7-8 PM. Overall forecast thinking remains unchanged as
modest dewpoints in the low to mid 60s and poor mid level lapse
rates will generally limit instability with ML CAPE in the 500
to 1000 J/kg range. Shear remains conducive for organized
updrafts with CAMs suggesting a few semi discrete cells tracking
from the mountains towards the coast that will have the
potential to reach severe thresholds. Storms will be capable of
both severe winds and hail with the highest likelihood for a
severe storm across central Maine zones. The 12Z CAM guidance is
in decent agreement that areas south of a line from KLEB to
KPWM will miss out on any storms or measurable rainfall.

Convection will wane through the first half of tonight with the
loss of heating while the front starts to stall across southern
NH. Drier air will work in from the north with limited chances
for additional showers overnight. Lows tonight will range
from the low 50s north to mid 60s south.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
The stalled front will provide a focus for clouds and showers
Thursday morning, mainly across southern zones. Low pressure
forming along the front will track across southern New England
through Thursday night. This low will bring more widespread
rainfall across the southern two thirds of the area Thursday
afternoon through Thursday night. Rainfall amounts will be
around 0.25 inches across central portions of the area and up
around 1 inch across southern NH through Thursday night. It
will be much cooler Thursday with highs in the 70s. PoPs will
decrease from north to south Thursday night with lows ranging
from the 40s north to upper 50s across the south.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Impacts and Key Messages
- Rain tapers off in the south Friday, followed by mostly dry
weather into next week

- Comfortable daytime highs and low humidity supporting cool
  nights

- Gradual warm-up into next week

Friday will be the coolest day of the forecast with broad troughing
aloft. At the surface, a weak shortwave will move off Delmarva
region, helping to drive the surface cold front well south of of our
area. This will allow any lingering precip across S NH to clear out,
leaving cool Canadian high pressure to dominate. With strong
radiational cooling and a crisp airmass, look for temperatures
to bottom out with lows in to 40s in the north, and 50s south
both Friday and Saturday nights. Can`t rule out some dense
valley fog each morning given the difference between water to
air temps. The expansive area of high pressure will serve to
keep mostly sunny skies, with a few cu in the mountains, and
fairly light N winds under 10 mph for Saturday. The high will
start to move east by Saturday night, allowing for some weak
return flow and gradual warming into early next week. Dry
weather will continue well into next week with the next chance
for rain possible midweek. Models are hinting at rain chances
midweek associated with a mid-level shortwave...but signals not
strong enough to pin point timing or extent of coverage.
Overall, the trend will favor seasonable temperatures and
mostly dry conditions Sunday through Tuesday.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
Short Term...There will be chances for scattered thunderstorms
through this evening mainly north of a line from KLEB to KPWM.
Confidence in coverage is not high enough to put into the TAF
except at KHIE. Otherwise mainly VFR will prevail through
tonight. Clouds thicken and lower Thursday into Thursday night
with MVFR cigs likely across southern NH Thursday afternoon.
MVFR cigs will likely spread north Thursday night.

Thursday Night through Sunday...Mainly VFR with localized valley
fog/attendant reductions in visibility possible each late night and
early morning.

&&

.MARINE...
Short Term...Winds and seas remain below SCA thresholds through
Thursday night. A front will slip through the waters this
evening bring the potential for a couple strong storms to track
into the waters. The front stalls south of the waters Thursday
will low pressure tracking along the boundary Thursday night.
This low will bring increasing northeast flow Thursday night.

Long Term...The period will start with northeast winds, but despite ample
mixing potential the strong high pressure centered over the waters
will keep winds 15kt or less. Winds will back on Saturday, with
return flow by Saturday night and Sunday. SW winds will again remain
under 15kt until Sunday night when a brief surge could mix in some
gusts around 20kt. Seas will generally be 1-3ft seas at the start of
the period will build to 2-4 ft by Sunday night with sw flow.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...Heat Advisory until 8 PM EDT this evening for NHZ012-013.
MARINE...None.

&&

$$

SYNOPSIS...
NEAR TERM...Ekster/Schroeter
SHORT TERM...Schroeter
LONG TERM...Jamison
AVIATION...
MARINE...