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FXUS61 KGYX 150621
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
221 AM EDT Sat Aug 15 2026

.WHAT HAS CHANGED...
No significant changes since the previous forecast cycle.

&&

.KEY MESSAGES...
1. High pressure will bring dry weather to start the weekend
with seasonably cool nights.

2. Rain accompanies a passing system Sunday night into Monday
morning. A period of heavy rainfall will be possible which may
result in nuisance flooding or ponding in poor drainage areas
for the morning commute.

&&

.DISCUSSION...
KEY MESSAGE 1 DESCRIPTION...

Canadian high pressure will continue to provide tranquil weather
conditions today. Mainly sunny skies this morning will becoming
partly cloudy this afternoon as some weak daytime instability
develops, resulting in a fair weather cu field. High
temperatures will be near seasonable averages, with readings
ranging from the lower 70s across the north to the upper 70s and
lower 80s south.

Mainly clear skies are expected tonight, which combined with
light winds and relatively low dew points will allow for
radiational cooling. Forecast lows range from the lower to
middle 40s across some interior valleys with upper 40s and lower
50s elsewhere. Valley fog is likely to develop overnight and
persist into early Sunday morning.

Sunday begins with high pressure overhead, quickly exiting east
into the open Atlantic. Surface return flow combined with a WSW
low level flow will begin to saturate the low levels while high
clouds overrun from the west. Right now, mid level saturation
isn`t likely until the late afternoon or evening, and this keeps
rain chances lower through the day until the evening and
overnight hours.

KEY MESSAGE 2 DESCRIPTION...

Forecast ensemble IVT plumes differ in magnitude and
trajectory, with a more northeastward segment from the ECMWF ENS
than the GEFS (a northward suppression, more progressive
through the Mid Atlantic). In line with this vapor transport in
the ENS, EFI QPF fields have also jumped comparing guidance from
Wednesday evening to Thursday evening`s runs indicating some
potential for an above average precipitation event. Shift of
tails however remains muted, with an extreme precipitation event
unlikely.

Warm cloud depth in deterministic models is impressive, with
runs of the GFS, ECMWF, NAM, and Canadian all depicting depths
greater than 12kft for a period late Sunday night and early
Monday morning. Coinciding with above normal PWATs around 2
inches, a period of heavy rain is becoming more likely, but
exact location and radar presentation will need to be resolved
with time.

One of the larger differences in guidance, and therefore an
important distinction between outcomes, is how far south the
trough or low cuts into southern New England. A track further
into southern New England could kink vapor transport, limiting
moisture depth and duration, while a flatter path across
northern New England keeps this SW moisture flux open, resulting
in more efficient rain processes.

Remaining rain tapers off through the day Monday, with drier
weather and a bit of a warmup through midweek as highs climb
into the lower to mid 80s. The next chance for rain then looks
to be Wednesday into Thursday as an elongated cold front
approaches from Quebec. It is yet to be determined if a wave
develops out of this front, but could offer some rain
enhancement depending on location through northern New England.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
Through 06Z Sunday: VFR conditions through Saturday night,
except at LEB and HIE where valley FG is likely both this
morning and tonight... mainly between roughly 06Z-12Z each day.
This will bring IFR-LIFR restrictions. Light and variable winds
early this morning become NW later today at 5-15 kts before
becoming light and variable again tonight. No enhanced LLWS is
anticipated through the period.

Outlook:

Sunday: VFR expected through the afternoon.

Sunday night: MVFR/IFR cigs in RA, RA may be heavy at times
limiting vis.

Monday: Decreasing RA coverage, improvement towards VFR likely
for points outside of the mountains.

Monday night and Tuesday: VFR. No sig wx.

Wednesday - Wednesday night: VFR. SHRA possible late ahead of
an incoming cold front.

&&

.MARINE...
High pressure will continue to result in winds and seas
remaining below SCA criteria through at least tonight.
Southerly winds increase Sunday, with gusts 25 to 30 kt
overnight into Monday morning. A low will cross northern New
England and then the coastal waters Monday. It is possible a low
level inversion keeps these gusts below SCA criteria. High
pressure passes through the Mid Atlantic into midweek, before
another cold front approaches from the west.

&&

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

&&

$$

DISCUSSION...Tubbs/Clair/Cornwell
AVIATION...Tubbs