Area Forecast Discussion
Issued by NWS Portland, ME

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094
FXUS61 KGYX 170630
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
230 AM EDT Tue Jun 17 2025

.SYNOPSIS...
Today will be a much cooler and cloudier day with a few showers
and drizzle at times. Conditions improve some Wednesday as the
onshore flow turns more southerly. Warmer temperatures are
expected along with a chance of late afternoon showers and
thunderstorms. A cold front approaches on Thursday with higher
chances for showers and thunderstorms. Friday and the weekend
will be drier but a few showers or thunderstorms cannot be ruled
out.

&&

.NEAR TERM /THROUGH TODAY/...
Nighttime microphysics satellite imagery and ASOS/AWOS
observations indicate that low-level stratus has moved onshore
and pushed inland across much of western ME south of the
foothills as well as portions of southeastern NH. Despite these
low ceilings, surface visibility has yet to be impacted in most
locations so far this morning but at least some patchy fog
remains possible. Northeast radar mosaic is beginning to show
some weak returns moving into southwestern NH with a few reports
of light rain in association with this activity. Latest hi-res
guidance suggests these light showers/drizzle will continue to
slowly progress northeastward through this morning. Temperatures
are primarily into the 50s and these readings will remain
nearly steady through sunrise.

Surface high pressure will remain northeast of the region today
with anticyclonic low-level southerly flow prevailing over the
local area. This combined with some increasing moisture from
broad WAA aloft will result in a partly to mostly cloudy day
with a few widely scattered light showers possible. The added
cloud cover combined with the onshore flow off the cool Gulf of
Maine will limit high temperatures to the 60s in most locations,
although parts of northern NH and towards the Moosehead Lake
region could reach the lower to middle 70s.

&&

.SHORT TERM /TONIGHT THROUGH 6 PM WEDNESDAY/...
A subtle H5 s/wv trof and associated vort max will cross this
evening, which will provide some added forcing for ascent and
thus and increased chance for scattered showers. Rainfall
amounts of between 0.10-0.20" are possible with perhaps a few
spots nearing 1/3rd of an inch. Patchy fog will once again be
possible with low temperatures generally within a few degrees
either side of 60.

A weak triple point will cross southern Quebec on Wednesday,
sending a sfc warm front northward across NH and portions of
southwestern ME. This will place much of the region into the
warm sector with high temperatures rebounding back into the 70s
to near 80 degrees (warmest inland). Skies will be partly to
mostly cloudy and a few diurnally driven showers/storms will be
possible during the afternoon and early evening.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Evening Update...No major changes to the long term portion of
the forecast with the implementation of the latest long range
NBM. Thursday remains the day to watch with a potent cold front
progged to sweep through the area with very warm daytime
temperatures. Depending on timing, a few strong to severe
storms are possible.

Previous Discussion...
Showers will mostly fizzle out Wednesday evening, and then
based on the light southerly flow continuing, will probably see
a return of fog and low stratus overnight that lingers into
Thursday morning.

A more potent cold front approaches on Thursday, and once the low
clouds and fog lift in the morning, it looks to be a hot day with
temperatures away from the coast reaching the mid 80s to low 90s
based on sounding profiles, perhaps mid 90s in NH. This front
will bring a chance of showers and storms to the area, with the
highest chances being across western and northern locations at
this time, and some storms have the potential to be strong to
severe depending on the timing of the front. There are lesser
chances of storms to the south and east of the I-95 corridor
where the seabreeze is more likely to bring in the more stable
marine layer.

The cold front quickly passes Thursday night with it becoming breezy
either late Thursday night or Friday morning and then continuing
during the day Friday. At this point in time, I have trended the
forecast higher than the NBM on wind gusts, but these may need to be
bumped up more in the future. Forecast soundings suggest 30-40 mph,
but there may be a window where gusts could top out in the 40-50 mph
range, per the top of the mixed layer. High temperatures will come
down from those of Thursday, but still expecting it to be warm with
highs in the 70s to lower 80s.

A 500mb high becomes centered over the southeast US with the ridge
axis extending northward across the Great Lakes on Saturday and
then across much of the eastern US by Sunday. While this will
bring generally dry weather here, it doesn`t mean that the
weekend will be completely dry as being on the eastern periphery
of an upper ridge can sometimes bring waves in on the northwest
flow. The operational GFS/ECMWF are latching onto a shortwave
in what almost would resemble an MCS sometime over the weekend,
but there is much disagreement on the timing and location of the
wave this far out other than the possibility is there.

Going into early next week, there is a growing signal in the global
models for a strong ridge of high pressure to further expand over
the eastern CONUS. Whether or not it extends far enough north
into New England to keep any waves in the west to northwest flow
and precip chances north of the area remains to be seen, but
there is more confidence in bringing in very warm to hot
conditions. With the 850mb temperatures being advertised, highs
could get into the 80s to low 90s Monday and then possibly
hotter just beyond the end of the forecast period.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Short Term...Low ceilings combined with patchy FG will continue
to result in IFR to LIFR restrictions through much of today.
Some improvements are possible briefly this afternoon across
some inland TAF sites before conditions deteriorate once again
this evening. Scattered -SHRA/-DZ is also possible at times. Low
ceilings and FG are then likely once again tonight with IFR/LIFR
restrictions. At least some improvement is then expected on
Wednesday but some restrictions could linger, especially at
coastal sites. Scattered showers and perhaps -tsra will also be
possible. Southerly flow of 5-15 kts will prevail through the
period. No LLWS is currently anticipated.

Long Term...A similar story is expected Wednesday night into
Thursday morning with LIFR to IFR conditions with low stratus
and fog possible with improvement during the day. A cold front
does approach and brings another chance of showers and storms
during the day Thursday evening and then diminishing in the
evening. Behind the front, sites with any restrictions will
return to VFR with west winds picking up Thursday night into
Friday with some potential for gusts 30-35 kt. Mainly VFR Friday
through Saturday with a few showers possible Friday afternoon.

&&

.MARINE...
Short Term...Southerly flow will prevail through the period
along with marine fog/stratus at times but winds and seas will
remain below SCA thresholds.

Long Term...A cold front approaches Thursday and crosses later
in the day or Thursday night and may reach SCA criteria that
last through portions of Friday. Another weak front may cross on
Friday before high pressure builds in south of the waters to
start the weekend, offering improving conditions. Another weak
low may approach the waters around Sunday. Also expect fog to
continue at times over the waters through Thursday or Thursday
night until the front passes.

&&

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

&&

$$

NEAR TERM...Tubbs
SHORT TERM...Tubbs
LONG TERM...Baron/Combs