294
FXUS61 KGYX 030354
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1154 PM EDT Wed Jul 2 2025

.SYNOPSIS...
A cold front moves offshore tonight providing our area with
fair dry weather and lower humidity. Another front will
approach Thursday afternoon with showers and thunderstorms, a
few of which could be strong to severe. That front will usher in
a much drier air mass 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 /UNTIL 6 AM THURSDAY MORNING/...
1150pm Update...With the weakening of showers and storms to the
west, have removed these chances from the overnight hours.
Otherwise, temperatures trends remain on track with winds
becoming light. Will see interior locations cool well under mostly
clear skies.

7pm Update...Forecast remains on track this evening. Looking
upstream, do have a well developed thunderstorm crossing the
Ontario/Quebec border that has slowly moved east over the last
few hours. With sustained elevated instability along its track
through the evening and overnight hours, added mention of some
isolated thunder tonight across northern NH and the western ME
border. Its very possible that the storm succumbs to the loss of
daytime surface instability in a few hours, but would rather
include the mention than not at this time.

Previous Discussion...
A modest drop in humidity was observed across the region as a
cold front stalled near the coast. This boundary combined with a
sea breeze could support a few pop-up showers in the Midcoast
this afternoon. The front will slowly proceed further offshore
overnight before washing out. Clearing skies and calm winds
behind it will allow temperatures to cool into the upper 50s to
mid 60s from N to S. Can`t rule out some pockets of valley fog,
but coverage will be patchy at best. The only exception will be
concerns for sea fog development from the midcoast eastward,
likely to impact coastal communities in that area late tonight
into the early morning.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Key Messages

 - Approaching front will bring rain and thunderstorms Thursday,
with gusty winds possible.

An upper-level trough dipping southeastward out of Quebec tomorrow
will pivot its attendant cold front through the local area early
in the late afternoon/evening. The height falls aloft combined
with modest instability support expanding widely scattered
shower and thunderstorms. Overall moisture is expected to be
quite a bit lower than the last few days, with PWATs only
around 1.25" for the majority of the event, limiting the heavy
rain potential. Although tomorrow`s moisture content is not
expected to be as high, surface heating promoted by mostly sunny
skies will allow for temperatures to rise swiftly into the upper
70s and low 80s. These warm temperatures may allow for MUCAPE
values of 1000+ J/kg for a few hours in the afternoon. This,
coupled with moderate 0-6km bulk shear values of 30-40 kts could
allow for severe weather in the afternoon and evening. As a
result, the SPC has our area in a Marginal (level 2/5) Risk for
severe weather, with damaging winds and hail as the main
threats. Storms are currently expected to initiate in the
mountains in northwestern Maine and northern New Hampshire before
moving 43towards the coast throughout the evening. The most likely
time for storms is 1-7 pm, possibly impacting any early 4th of July
celebrations. Any severe threat would most likely be during the
afternoon and early evening hours. There are still some disparities
between hi-res guidance, with some models placing the front back in
northwestern ME by peak heating hours whereas others already have
the front nearing the coastal areas.
Additionally, while low level lapse rates appear favorable,
relatively weak mid level lapse rates could limit the amount of
instability as well as the threat for hail. As a result, gusty
winds look like the most likely threat with DCAPE values of
600-700+ likely. Drier air will filter in behind the frontal
passage, with lowering dewpoints and clearing skies. This will
support a cool night with lows in the 50s.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Long Term Update: Made minor adjustments to the extended
heading into early next week. A return to hot temperatures
appears likely Sunday and Monday ahead of a cold front that
passes later Monday. There remains uncertainty on timing of this
front, but there should be sufficient time ahead for
temperatures to rise into the lower 90s. Removed mention of
thunder Sunday evening as for now, frontal passage into Monday
still encompasses a wide envelop. With the arrival of the front
later Monday, this is when thunder chances increase. There is
also variance in orientation of the front as it nears the
region. A less progressive solution has been hinted at, and this
could keep the region in warm, moist air for longer into Monday
evening. Lingering IVT depicts this well, albeit with weakening
values as source moisture is stretched over continetial
airmass.

Previously:
A more comfortable airmass settles in Friday featuring
highs mainly in the mid 70s to lower 80s with lower
dewpoints/humidity. As the upper low crosses into the eastern
part of Maine, it may set off a few showers and a storm or two
across northern areas, but the vast majority of the area will
stay mostly to partly sunny and dry. Friday night temps will be
mostly in the 50s, but northern valleys may see the upper 40s.

Mostly dry conditions are expected over the weekend as a 500mb ridge
steadily builds in, although models are hinting at a weak wave
moving in on the northwest flow aloft, which may bring a few showers
across the north Saturday night. Otherwise, the building ridge will
bring a warming trend with highs in the low to mid 80s Saturday, and
by Sunday, lower 90s are possible across portions the area as 850mb
temps are progged to get to around +19C with humidity also creeping
back upward as a front approaches from the north.

Speaking of the front, there`s been a slowing trend in its approach,
so chances for precip have continued to decline for Sunday with most
expected to stay dry at this point, except maybe far northern
areas where PoPs remain at 20-30%. The front begins pushing
southward early next week with the higher chances for showers
and thunderstorms coming Monday into Tuesday. It looks to remain
hot Monday, and then temperatures may come down Tuesday into
Wednesday depending on how far south the front progresses.

&&

.AVIATION /04Z THURSDAY THROUGH MONDAY/...
Short Term...VFR conditions in place with only high clouds (20k
ft) draped over southern terminals from a stalled frontal
boundary. High humidity and nearly-calm conditions over the
waters could produce some marine fog over the midcoast, with
some IFR conditions possible at RKD late tonight/early Thursday.
Otherwise VFR conditions likely. Widespread MVFR cigs and vis
expected to start by 17-19z and linger through 00Z with hit/miss
convection. Some stronger storms may also pose a risk of gusty
winds up to 35-40 kt at times, but confidence too low to include
Prob30 at this time.

Long Term...Mainly VFR Friday with a couple of showers
possible, mainly north of an AUG-HIE line. Over the weekend,
prevailing VFR during the day, but there may be valley fog at
night. A front approaching from the north may bring a chance of
showers and storms as early as Sunday, but it`s more likely
showers and storm hold off until Monday.

&&

.MARINE...
Short Term...Washed out frontal boundary will stall just of the
coastal waters tonight. SW flow will continue with speeds
generally less than 15KT, enhanced by an afternoon thermal
gradient. Tonight winds will ease further and turn to the north
or variable as the front weakens and drifts further offshore.
Winds will back to the SW ahead of another weak front Thursday,
but again winds will remain 10- 15kt or less generally. Seas
will generally be 1-3 ft with weak winds and <1ft swells of 9
seconds.

Long Term...SCA conditions not expected Friday with offshore
flow behind a frontal boundary...but may become more variable in
the afternoon as a seabreeze tries to develop. High pressure
becomes centered southeast of the waters over the weekend into
early next week as a frontal boundary approaches. The pressure
gradient may become tight enough to bring SCA conditions as
south to southwest winds increase in the late Saturday through
Monday timeframe.

&&

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

&&

$$


NEAR TERM...Cornwell/Jamison
SHORT TERM...Venarsky
LONG TERM...Combs/Cornwell