Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 182252
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
652 PM EDT Fri Jul 18 2025

.SYNOPSIS...
Post frontal breezy westerly wind gusts will weaken this
evening. Seasonable and dry weather continues Saturday, but
chances for rain and thunderstorms will increase on Sunday.
Storms may contain brief downpours. Early next week we return
to fair and seasonable weather.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
650 PM Update...Little change to the going forecast for the
evening and overnight. Winds will diminish and skies will remain
clear.

Previously...

Impacts and Key Messages:
* No significant weather impacts expected

High pressure continues to build in this afternoon which will
help to loosen the pressure gradient and keep gusts weakening
through the evening, and eventually go calm. This along with
clear skies looks like a favorable setup for radiational
cooling, dropping temperatures into the mid to upper 40s north
of the mountains, mid to low 50s in the foothills and valleys,
and mid to upper 50s on the coastal plain.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Impacts and Key Messages:
* No significant weather impacts expected

High pressure remains in place Saturday making for another
mostly clear day. Canadian wildfire smoke will pass to the north
of the region tomorrow with zonal flow keeping it more elevated
and out of our area. Some hazy skies may be evident in northern
zones and to those recreating in the higher terrain, but it
will be subtle enough to not include in the forecast.
Temperatures climb into the 80s south of the mountains, and into
the mid to upper 70s to the north.

Low pressure begins its approach from the Great Lakes Region
with broad 500 mb troughing developing as well. This will make
for a cloudier night and thusly warmer low temperatures.
Locations north of the mountains look to bottom out in the upper
50s with locations to the south more in the low to mid 60s. A
more southwesterly flow develops overnight as well which may
hold southeastern New Hampshire in the upper 60s for lows as the
more moist flow increases dewpoints there. Depending on the
timing of the front it is possible a few showers sneak into the
area overnight, mainly in the north, but the bulk of the showers
and potential thunderstorms look to hold off until after
sunrise.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Overview: Broad upper level trough will move unsettled weather
through the region into Sunday. After a cold front pushes
through, drier conditions take hold of New England through
Wednesday. Late week, low pressure passes to the north bringing
frontal systems through New England as well as the chance for
rain.

Potential Forecast Impacts:

* Thunderstorm intensity on Sunday hinges on the progression of
  a cold front swinging through New England. Stronger storms
  containing gusty winds will be possible where daytime heating
  can build ahead of the front.

Details: By Sunday morning, low pressure will be sliding east
toward New England. There remains differences in timing and
shape of this feature and associated fronts. Some solutions have
a more NE translation of the front, while others bring a more
easterly component. Showers remain likely for much of the area,
but better timing and coverage will need to come into focus
over the next few iterations of data.

Continue to see building instability in portions of SE NH and
coastal/interior southern ME through the daytime hours. This is
ahead of the front, so amount may vary on how quickly the front
is passing. Early breakdown of values show potential for a good
CAPE/shear balance for mini-supercell development ahead of the
front. This is based on resultant BRN numbers around 18-20 from
~2000 j/kg of CAPE and 35 kt of 0-6km shear. Would expect CAPE
and other instability parameters (such as lapse rates) to have
the greatest fluctuation and influence of severity here. Where
storms do develop in this environment all hazards will be
possible, but most probable at this time are gusty winds.

With the passage of the cold front in the evening, Monday
shapes up to be very pleasant (similar to today, Friday). NW
winds remain breezy through the day with some upslope clouds
keeping mtn daytime highs about 10 degrees cooler than interior
areas. Slackening winds and clear skies under high pressure may
bring a cool Monday night where lows dip into the mid 40s in the
mountains and lower 50s elsewhere.

From there, it is a slow warming trend into late week with the
next chance of rain Thursday with another passing low and cold
front.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
Short Term...VFR will prevail through Saturday. Some lowering
of ceilings toward MVFR is expected Saturday night as low
pressure approaches the region. Some showers and possibly
thunderstorms may near HIE in the early hours of Sunday morning.
No low level wind shear is expected at this time.

Long Term...MVFR with some areas of IFR on Sunday with SHRA and
later in the afternoon TS for at least SE NH terminals. Coastal
fog may develop along the ME midcoast for much of Sunday. A cold
front passing will improve conditions with wind shifting NW
Monday. Gusts to 25 kt will be possible before slackening Monday
night. VFR continues into Tues and Wed.

&&

.MARINE...
Short Term...Wind gusts and seas remain below SCA criteria
through Saturday night as high pressure builds over the region.
Winds shift from northwesterly to southerly by Saturday morning.

Long Term...Below SCA conditions Sun - Wed. A cold front will
approach the waters Sunday evening, passing into Monday morning.
Showers/storms may accompany the frontal passage, with a NW wind
shift.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Beach Hazards Statement from Saturday morning through Saturday
     evening for MEZ027-028.
NH...None.
MARINE...None.

&&

$$

SYNOPSIS...
NEAR TERM...Baron/Ekster
SHORT TERM...Baron
LONG TERM...Cornwell
AVIATION...
MARINE...