Area Forecast Discussion
Issued by NWS Portland, ME

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449
FXUS61 KGYX 241911
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
311 PM EDT Sat May 24 2025

.SYNOPSIS...
Scattered showers will persist into early this evening as low
pressure moves towards New Brunswick, Canada. It will take until
Sunday before we get some slow improvement to the weather and
temperatures with drier and warmer temperatures going into
Monday. A warming and drying trend will continue into the
middle of next week, but another period of unsettled weather is
then likely once again by the end of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Satellite imagery and latest RAP depicts the center of the upper low
now over New Brunswick with the surface low nearly over the same
area, per latest observations. Vort maxes associated with a couple
of shortwave troughs stemming from the upper low will cross the area
through early this evening and capitalize on the low-level
instability generated from the steepening lapse rates to provide
fairly high coverage of showers. For the next couple of hours,
I have 50-60% PoPs across much of western ME and then 30-40%
farther to the south and west across central and southern NH.
These showers are capable of producing brief heavy downpours and
maybe even graupel in a couple of them. Once this initial wave
passes, we should start seeing a downward trend in showers
toward early evening and then even moreso toward and after sunset
with the loss of the diurnal instability. For tonight, the
upper low continues to slowly move eastward and expect lingering
showers to stay mostly in the mountains (and snow showers in
the highest elevations) with partly to mostly cloudy skies to
the south. Winds will again be light, and given the recent
rains, patchy fog will again be possible. Lows will be mostly in
the 40s.

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
The stacked low pressure will be centered in the Nova Scotia
vicinity on Sunday, setting up a northwest flow across New England.
Upsloping will keep skies mostly cloudy from the mountains northward
along with scattered showers, possibly still mixed with snow in the
highest elevations. For areas to the south, forecast soundings
depict steep low-level lapse rates resulting in a small amount of
instability during the day. So even if there is some clearing
tonight or early in the morning, sufficient moisture and the LL
instability will probably bring periods of mostly cloudy skies
during the day and perhaps a few showers, but chances are much
lower than today with PoPs limited to about 20%. Temperatures
will tack on a few degrees from today`s highs with most expected
to reach the upper 50s to lower 60s, except a bit cooler still
in the mountains.

Shower chances mostly end around sunset, except could last a little
longer in the mountains. Otherwise, expect partly cloudy skies
overnight with low mostly in the 40s. MOS guidance is suggesting mid
30s possible across the north and may result in patchy frost.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Overview: High pressure expected for the first half of next week,
though a diurnal shower or two can`t be ruled out across western NH.
Towards the end of the week, two upper-level lows merge over New
England. The upper-level lows could bring more unsettled and cooler
weather next weekend.

Details: The work week starts off mostly clear, as high pressure
moves in from the Great Lakes. Diurnal heating should allow for
warmer high temperatures approaching 70F most places, and a little
instability could develop through the day as well. Northerly
flow over the mountains may provide enough forcing for a couple
pop-up showers to form Monday afternoon. Showers will be weak,
and shouldn`t produce much rainfall. Any showers will fizzle out
quickly after sunset.

A mid-level ridge starts to build in Tuesday, with a warming trend
expected in the first half of the week. High temperatures look to be
in the mid-70s across most of the area, with cooler temperatures in
the mountains and along the immediate coast. Ridging and warmer
temperatures continue through Wednesday, with Wednesday looking like
the warmest day of the week, but not much warmer than Tuesday.

Towards the end of the week, two upper-level lows could barrel
down on the northeast - one from the west and one from the
north. The combination of these UL lows likely suggests that
unsettled weather and showery conditions are likely starting
Thursday and possibly continuing through the weekend.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
Short Term...Currently expecting a mix of MVFR and VFR ceilings
through tonight and early Sunday. Sites mostly likely to see
periods of MVFR through Sunday will be LEB and HIE, but AUG and
RKD could see some too. Otherwise scattered showers persist this
afternoon/early evening then gradually fade beyond 00Z through
tonight. These showers may produce brief MVFR vsby, but then
will have to watch for fog development tonight. Mostly VFR
Sunday into Sunday night with a few showers developing Sunday
afternoon, but HIE may continue to see MVFR ceilings.

Long Term...A few showers may lower restrictions briefly on
Monday, with VFR expected otherwise. High pressure and clear
skies should allow for fair weather through the first half of
next week, with no other opportunities for restrictions
expected.

&&

.MARINE...
Short Term...Conditions are expected to remain below SCA levels
through Sunday night. Low pressure to the northeast of the
waters will keep winds out of the northwest, but these may
become more west to southwesterly Sunday afternoon as a
seabreeze tries to develop.

Long Term...Fair marine conditions are expected through the
first half of next week, with variable winds at 4-10kts and
1-2ft seas expected Monday through Wednesday.

&&

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

&&

$$


NEAR TERM...Combs
SHORT TERM...Combs
LONG TERM...Palmer