001
FXUS61 KGYX 260326
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1126 PM EDT Fri Apr 25 2025

.SYNOPSIS...
Low pressure approaches from the Ohio Valley this evening
bringing a soaking rain through Saturday. Low pressure is slow
to exit Sunday with continued chances for showers. High
pressure builds in Monday for fair weather and a warming trend
into Tuesday. The next frontal system will cross Tuesday night
into Wednesday.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
1130 PM Update... The first batch of light rain is now located
over the north and towards the Penobscot Valley with the next
round of showers moving into southern NH. This activity will
continue to lift northward overnight with perhaps some patchy
fog developing late.

Previously...
700 PM Update... An area of light rain persists at this hour
from southern Coos county in NH and extending southeastward
towards Lewiston/Auburn and central Cumberland county. This rain
is slowly advancing east-northeastward and is associated with a
stationary front. Have increased PoPs across these locations as
measurable rainfall of a few hundreds of an inch are likely but
also lowered PoPs in most other locations. Otherwise, just
blended in the latest surface observations at this time.

Previously...
Showers focused along a stationary front have been slowly moving
across central NH this afternoon. So far these have been fairly
light, and will tend to pull north ahead of the larger batch of
rain arriving after midnight into early Saturday. Temperatures
remain mild tonight, retreating to the 40s to around 50.

Low pressure will continue to deepen over the Great Lakes this
evening and into early Saturday morning as upper trough
amplifies into southern Ontario. Rapidly strengthening LLJ off
the New England coast increases IVT and PWATs. Steadier rain
looks to make its way into SW NH around daybreak and then
ME around 8am.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Much of Saturday looks to be a washout, but rain rates and
amounts keep flooding chances very low. The soaking rain will
be beneficial for an otherwise dry April. As of Friday
afternoon, Portland currently runs 0.7" below normal for
rainfall this month, with Gray (0.93") and Augusta (0.89") also
standing to benefit.

All in all, the system is fairly progressive, likely driven by
the upper trough not developing a negative tilt until the Gulf
of Maine. Precip efficiency may be held back due to a thinner
warm cloud layer, but moderate to heavy rain is forecast to be
falling through the morning. PWATs into the late morning may
near GYX`s daily max 12z RAOB value of 1.35". Coastal
enhancement has been shown in today`s CAMs, with increased
values around Casco Bay up the Midcoast. Elevated instability
could also aid in some rumbles of thunder over the coastal
waters and along the coast Saturday.

The main period of rain pushes north through Saturday afternoon,
with showers wrapping up the daytime. These become more isolated
into the evening as dry air wraps around the low. Temps remain
nearly steady until after midnight when NW winds arrive to bring
cooler temps. Additional shower development is likely across
central ME as some instability develops below the low.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
04Z Long Term Update... Little change from the previous forecast
in the latest NBM guidance. Other than a few showers possible
Tuesday night, it looks relatively dry through the middle of
next week before rain chances increase late week.

Previously...
Low pressure will be deepening over Downeast Maine Sunday before
exiting into the Atlantic Sunday night. High pressure builds in
Monday and Tuesday for dry weather and an upward trend in
temperatures. A frontal system will cross Tuesday night and
Wednesday with high pressure returning Thursday.

Sunday will be cool and cloudy with a surface low over Downeast
Maine and an upper low crossing overhead. The 12Z model suite is in
good agreement that precipitation will continue over the
northern half of the CWA with colder air aloft allowing rain to
change to snow in the mountains. Some dry air will wrap into the
system Sunday morning leading to lower chances for rain showers
south of the mountains. Highs will range from the mid 40s north
to mid 50s south. As the low deepens to our east, north to
northwest winds will increase Sunday afternoon with gusts 25-30
mph. Chances for precipitation diminish Sunday night with breezy
NW winds continuing into Monday.

Monday will be dry will mostly sunny skies as high pressure builds
in from the west. A NW gradient will persist into the afternoon with
winds gusting 20-25 mph until high pressure moves closer to overhead
Monday evening. Highs will range from the low 60s north to low 70s
south. Heights build over New England Tuesday with high
pressure shifting to the south. This will allow for warmer air
to advect into the region bringing highs well into the 70s
across NH and interior western Maine. Southerly winds will
advect cooler marine air into the coast where highs will mainly
be in the 60s.

Clouds increase late Tuesday into Tuesday night as a cold front
starts to shift southeast out of Canada. This front will slowly
cross overnight and Wednesday bringing mainly chances for showers.
Chances for showers will diminish through the day Wednesday as the
front pushes offshore. High pressure and cooler air arrive for
Thursday with the next system poised to approach Friday.

&&

.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
Short Term...VFR this afternoon and evening. Coastal terminals
may see ceilings fall quicker this evening. A bank of low
stratus or fog may move onshore mid to late evening. This will
bring the possibility of quick onset IFR to LIFR ceilings.
Visibility restrictions are more uncertain, but may fall to
IFR/LIFR after midnight in fog.

Elsewhere, ceilings will tend to lower to MVFR/IFR after
midnight. SHRA becomes more widespread across all terminals after
midnight, with RA more continuous through Saturday morning and
early afternoon.

Strengthening winds off the surface will create LLWS Saturday
morning with increasing rainfall rates.

IFR continues Saturday, with improvement towards VFR Saturday
night for most southern NH and far southern ME terminals.

Long Term...Low pressure over Downeast Maine Sunday will
maintain steady NW winds gusting to around 20 kts. Low cigs and
showers will bring the threat of at least MVFR, especially at
KAUG, KRKD, and KHIE. Mainly VFR Monday and Tuesday before a
front crosses Tuesday night into Wednesday that will bring the
chance for brief restrictions in showers.

&&

.MARINE...
Short Term...A stationary front remains over the waters this
afternoon as low pressure strengthens over the Great Lakes
tonight. This low will dive into New England Saturday. SCA
winds and building waves are forecast, with heavy rain and the
chance of a rumble of thunder. Fog will also likely reduce
visibility. The stacked low moves over the coastal waters
Saturday night, bringing lighter wind gusts but wave heights
slow to slacken.

Long Term...NW winds and elevated seas will likely continue SCA
conditions Sunday into Monday morning. High pressure crosses the
waters Monday and Tuesday with winds and seas below SCA
thresholds. South to southwest winds increase late Tuesday ahead
of a cold front with SCA conditions possible by Tuesday night.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory from 6 AM Saturday to 8 PM EDT Sunday for
     ANZ150-152-154.
     Small Craft Advisory from 10 AM Saturday to 2 PM EDT Sunday
     for ANZ151-153.

&&

$$

NEAR TERM...Tubbs
SHORT TERM...Cornwell
LONG TERM...Schroeter/Tubbs