Port Clyde, Maine Weather Forecast Discussion

515
FXUS61 KGYX 301814
AFDGYX
Area Forecast Discussion
National Weather Service Gray ME
214 PM EDT Tue Sep 30 2025
.SYNOPSIS...
Cooler air will filter in behind a cold front as high pressure
settles in at the surface. Temperatures on Wednesday and
Thursday will stay in the 60s during the day, and overnight
widespread 20s and 30s are forecast. Frost will be possible for
many locations, even near the coast. Starting Friday warmer
conditions will return to the area and winds become
southwesterly once more. But much like most of our discussions
over the last few months, little rain is in sight.
&&
.NEAR TERM /THROUGH TONIGHT/...
Current radar and satellite imagery shows mostly clear skies
over the area, with some very dry air present and light high-
level clouds in southern New England. Tranquil weather is
expected through the remainder of the afternoon.
Tonight, low-level CAA and radiational cooling should allow for
temperatures to bottom out substantially, especially across the
north. Low temperatures will range quite a bit, from near 40F
in the Midcoast, to upper 20s in many low-lying areas and
valleys north of the mountains and along the CT river valley.
Widespread frost is likely across the north. A Frost Advisory
has been issued for this area. In addition, some patchy fog may
form overnight in this area as well, though fog should mix out
by tomorrow morning.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
An upper-level trough in the Canadian Maritimes will dig and
deepen tomorrow, allowing for persistent northerly winds aloft
and low-level CAA through the day. Temperatures will be
noticeably colder, with highs in the lower 60s along the coast
and in southern NH. Highs may struggle to even get to 60F north
of the mountains and in the Maine foothills. Otherwise, clear
skies and a light breeze is expected.
Another frosty and chilly night is expected Wednesday night. Clear
skies and calm winds should allow for radiational cooling in most
places. Low temperatures are expected to be in the upper 30s in
the south, with upper 20s in the north.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Key Message: High pressure continues to dominate the weather pattern
as dry conditions persist. Expect a warmup through the weekend with
high temperatures returning to well above average values for this
time of year.
Impacts: Lack of rain will contribute to worsening drought
conditions. Frost is likely across much of the forecast area
Thursday night into Friday morning.
Forecast Details: The long term starts with an upper level ridge
axis approaching New England and expansive high pressure settling in
at the surface. The ridge axis will slowly move overhead through the
day on Thursday as it deamplifies. With northerly flow making it`s
way around the high pressure through the first part of the day, we
will see seasonable highs (maybe slightly below average in some
locations) on Thursday, mainly in the mid 50s to the mid 60s. A dry
airmass will also lead to widespread dewpoints in the 30s through
the day on Thursday with afternoon relative humidity dipping into
the 30 to 40 percent range over most of the forecast area. While the
dry conditions could lead to some elevated fire weather concerns,
winds will be fairly light with high pressure in the vicinity.
The center of high pressure will slide south Thursday night into
Friday morning, shifting light winds to out of the west southwest.
With light winds in place, we could see radiational cooling but some
guidance suggests at least some mid to high clouds over the region.
Will still go a bit cooler than straight NBM guidance with
uncertainty about how dense these clouds will be. Lows should mainly
being in the 30s with a few upper 20s in the usual cold spots and
some lower 40s along the coast. Widespread frost will be possible
overnight and the usual valley fog.
A shortwave will move over the top of the flattened ridge Friday
night into Saturday, but it should remain well to the north of our
area keeping the forecast dry. A new ridge then pops up to our west
and the axis approaches through the rest of the weekend. Model
consensus has the ridge axis moving across our area sometime in the
Sunday/Monday time frame, which should transition our area into
southwest flow aloft. This potential pattern shift could lead to a
return of precipitation chances early to mid week but considerable
uncertainty remains regarding details this far out. Dry weather
through the long term forecast period does signal the potential for
worsening drought conditions.
Regarding temperatures, we start to warm on Friday with highs mainly
in the lower 60s to lower 70s. The warmup then continues through the
weekend with some lower 80s back in the forecast across southern New
Hampshire and western Maine on Saturday and even more readings in
the lower 80s on Sunday. Above average temperatures persist into the
beginning of next week.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Short Term...Mostly VFR expected through Thursday morning. Some
patchy fog may lower restrictions tomorrow and Thursday morning
in LEB and HIE.
Long Term...With high pressure in control, VFR conditions are
likely through most of the long term with generally light winds.
However, the typical valley fog (LIFR/IFR visibilities) will be
possible each night, most likely impacting KHIE and KLEB.
&&
.MARINE...
Short Term...SCA Conditions will continue through Thursday
morning, as 2 tropical cyclones to the southeast of New England
continue to move to the east. Seas of 4-6ft will increase to
5-8ft on Wednesday, before returning to 4-6ft for Thursday.
Light and variable winds are expected over the waters this
afternoon, with winds becoming northeasterly at 23-29kts by
Wednesday morning. These winds will continue through the day,
but slowly shift from northeasterly to northerly by the end of
the day. Winds slacken Wednesday night, becoming 18-23kts by
Thursday morning.
Long Term...Seas will continue to relax through the day on
Thursday but SCA conditions will likely linger through much of
the day outside of the bays.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Frost Advisory from 1 AM to 8 AM EDT Wednesday for MEZ007>009-
     012-013-018-033.
     High Risk for Rip Currents until 8 PM EDT this evening for
     MEZ024>027.
NH...Frost Advisory from 1 AM to 8 AM EDT Wednesday for NHZ003>006.
     Freeze Warning from 1 AM to 8 AM EDT Wednesday for NHZ001-002.
MARINE...Small Craft Advisory until 8 AM EDT Thursday for ANZ150-152-
     154.
     Small Craft Advisory from 8 AM Wednesday to 8 AM EDT Thursday
     for ANZ151-153.
&&
$$
NEAR TERM...Palmer
SHORT TERM...Palmer
LONG TERM...Hargrove

NWS GYX Office Area Forecast Discussion