255
FXUS61 KGYX 050232
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1032 PM EDT Fri Oct 4 2024

.SYNOPSIS...
High pressure centered offshore will provide dry weather this
evening before a cold front crosses the region overnight into
Saturday morning. This front will bring scattered showers to the
region. High pressure builds back into the area for the second
half of the weekend. The next frontal system crosses Sunday
night into Monday.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
1030 PM Update...Little change to the going forecast. Continuing
to track fog and low clouds. Showers will be arriving in western
zones, especially in the mountains in a few hours.

7 PM Update...Not many changes to the going forecast this
evening. Backed off on the starting time for Likely PoPs a
smidge as the shower activity is still well off to our west.
Otherwise, low stratus and fog continue to move onto the coastal
and central zones.

Previous...

A weak upper level trough and cold front will approach the
region tonight. Ahead of this system, a southerly gradient will
allow for stratus and a fog bank in the Gulf of Maine to come
onshore tonight. This is reflected well in the latest HREF
scenario bringing low visibilities initially to the coastline.

Showers will cross the forecast area overnight in association
with our latest weak system. The greatest chance for
precipitation will be over northern and eastern portions. The
cloud cover will keep the overnight temperatures relatively
uniform across the region with upper 40s in the north to mostly
lower 50s in the south.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY/...
Any scattered showers Saturday morning into the midday hours
over northern and eastern areas will shift east of the region as
high pressure slowly builds in from the west. Increasing
sunshine can be expected especially over downslope regions with
a northwest gradient.

Very little in the way of cold air advection will accompany the
passage of this system and with nearly full sunshine downwind of
the mountains, temperatures will climb into the lower 70s over
southern areas with 60s in central zones and 50s in the
mountains.

The ridge will crest over New England Saturday night. With clear
skies, light winds and lowered surface dew points, radiational
cooling will result. Expect a chilly night with lows falling
into the 30s across the north and some of the interior valleys
and 40s elsewhere. Patchy fog will result.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Overview: High pressure starts the forecast period on Sunday.
High clouds encroach in the afternoon as an elongated cold front
nears the region. Showers arrive overnight into Monday morning
as this front passes overhead. Much cooler conditions arrive
behind this front for the middle of next week, with temperatures
running a few degrees below normal.

Details: High pressure overhead should keep much of the region
in mostly sunny conditions through the afternoon. Residual
moisture towards central Maine will tend to keep some clouds
around, and daytime highs may be held in the lower 60s because
of this. Elsewhere, mid to upper 60s are forecast.

Stacked low pressure near James Bay swings an elongated cold
front through the region Sunday night into Monday. This will
bring a ribbon of rain passing through New England during this
timeframe. Deterministic guidance is still varied with its
timing, and ensemble guidance is showing this as a fairly wide
plume of precip. Looking at isentropic analysis, the ribbon of
deeper moisture is actually not too wide as it passes overhead.
Thus there may only be a period of wetting rain crossing the CWA
with lighter showers or drizzle on either side. Tried to
accentuate the likeliest window of showers, late Sun night
early Monday morning, but uncertainty with timing and coverage
should keep this window a bit wider.

Once the front has passed off the coast, low level moisture
lingers, especially in the upslope regions. There is a chance
higher summits of the Whites see some flakes falling towards
the end of the event. Temperatures aloft will continue to cool
into Monday evening, and summit conditions fall below freezing.
However, deeper moisture may be out of the area by that time.
With enough low level moisture lingering, would expect riming to
take place Monday night in cloud, but flakes could be hard to
come by.

Monday night really kicks off the cooler trend with combined CAA
and some radiational cooling if cloud cover cooperates.
Widespread lows fall into the lower 40s with upper 30s to the
north. For Tuesday, highs only reach into the lower 60s and
upper 50s, with higher elevations above 2500 ft falling below
freezing or around this mark. Upslope flurries will be possible
during the afternoon given the moisture and low level lapse
rates. Winds will also be increasing for the higher terrain,
with wind chills falling to the teens and single digits.

Into midweek, the bulk of the CWA trends dry, but will see
continued chances of showers in the mountains. Guidance does
bring some precip into central ME and the coast, but this may be
more a function of cooler air moving over the `steamy` Gulf of
Maine waters generating low cloud decks than actual precip. Thus
not much confidence is this coming to fruition as measurable
precip.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Short Term...IFR and LIFR conditions developing this evening.
Lowest ceilings and visibilities will be along and near the
coastline. Conditions improve Saturday with downslope winds with
localized MVFR and IFR conditions outside the mountains.

Long Term...Periods of MVFR ceilings linger in central Maine
Sunday, expanding to include the remainder of NH and ME
terminals Sunday night. IFR conditions will also be possible.
These continue during the day Monday as SHRA passes and a NW
wind shift late. Conditions may not improve until Tuesday when
categories trend towards VFR in the morning.

&&

.MARINE...
Short Term...South winds will increase tonight but remain below
SCA thresholds. There will be patchy to areas of fog which
reduce visibilities throughout the night with scattered showers.
Winds switch to the west and then the north bringing drier
conditions over the waters.

Long Term...An SCA may be needed for the waters Monday as a cold
front and embedded low pressure pass over the waters. Wave
heights build 5 to 7 ft amid the consistent onshore flow
through Mon. Winds shift offshore Mon evening into Tuesday
behind the front.

&&

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

&&

$$