Area Forecast Discussion
Issued by NWS Portland, ME

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399
FXUS61 KGYX 060639
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
239 AM EDT Mon Oct 6 2025

.SYNOPSIS...
Near record warmth remains in the forecast through Tuesday
afternoon. Widespread 80s are expected of a cold front that will
cross the region late Tuesday into Wednesday. This front will
bring us the best chance of rain for the remainder of the week
as well. For many areas it will be one of a handful of the
rainiest days in the last three months, but that is not saying
much. Behind the front cooler air will arrive but that will come
with continued dry weather into the weekend.

&&

.NEAR TERM /THROUGH TODAY/...
Any valley fog will scatter out quickly after sunrise. Surface
temps are expected to rise fast with a dry air mass in place and
very warm temps aloft. Deep southwest flow will transport 925 mb
temps of 20 or 21C across most of the forecast area. The dry
surface and wind direction for some favored downslope warming
will push surface temps even warmer than the 925 mb values would
suggest. So with widespread readings pushing the mid 80s and
good mixing leading to dewpoints remaining in the 40s in
places...minimum RH values in the afternoon will bottom out at
or below 30 percent. With the elevated fire weather conditions I
will issue a special weather statement for all zones in ME.

&&

.SHORT TERM /TONIGHT THROUGH 6 PM TUESDAY/...
It will be another mild night for this time of year...with
southwest winds likely stirring thru much of the night. As such
I do not expect as much in the way of valley fog...so I have
reduced the length of time it is in the grids compared to
previous nights.

That deep southwest flow remain in place Tue...and temps will
once again soar ahead of the approaching cold front. Even if
there is a little more in the way of cloud cover later in the
day...some compressional warming ahead of the front should help
to offset that. Increased moisture advection should help RH
values remain in the 40 to 50 percent range during the day. Late
in the afternoon showers may begin to push into the forecast
area from the northwest...but the bulk of the rainfall will hold
off until after sunset.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Long Term Update....A strong cold front and trough of low
pressure will cross from north to south Tuesday night into
Wednesday morning, bringing our best chance for widespread
measurable rainfall. Rainfall amounts currently look to be
generally between 0.50-0.75", with perhaps a few spots
approaching an inch. Rain looks to end quickly on Wednesday
morning but some lingering showers will be possible until early
afternoon. Sharply colder temperatures can be expected with
daytime highs around 15-20 degrees cooler than those of Tuesday.
Lows Wednesday night will be into the 30s in most locations
with sub- freezing values across the north and in some valleys.
Even colder air arrives for Thursday with highs only into the
50s to lower 60s from north to south. Widespread frost/freeze
conditions are then likely Thursday night with lows near or
below freezing in many locations, especially away from the
immediate coastline and urban centers. A slight moderating trend
is then likely through the remainder of the week and weekend
but daytime highs will only warm to around seasonal averages.
Another dry spell looks likely as well.

Previous discussion...The 12Z model suite and available CAM
guidance suggest an axis of rain and perhaps some embedded
thunder will press into the area from the northwest Tuesday
evening. Rain will spread southeast Tuesday night with much of
the area likely to receive some beneficial rainfall through
Wednesday morning as an axis of PWATs up to 1.5 inches moves in
ahead of the front. As the the frontal passage will occur at
night, any instability will be waning reducing the probability
of heavier rainfall rates from convective processes. Ensembles
show a large spread in QPF ranging from less than a tenth of an
inch to greater than 1.25 inches. Have trimmed down the NBM QPF
based on this large spread with going forecast calling for most
areas to see around 0.75 to 1.0 inch of rain.

Rain showers will linger along the coast into Wednesday morning
with drier air arriving Wednesday afternoon. Cold air advection
and deep mixing will bring gusty NW winds with gusts around 25
to 30 mph. Downsloping will help bring highs Wednesday close to
70 degrees along coast while northwest zones will see highs only
in the 50s. High pressure builds in Wednesday night through
Friday for dry conditions. High pressure overhead Thursday
night will promote radiational cooling with lows in the 20s to
low 30s and may be the coldest night of the season for areas
south of the mountains. Temperatures moderate into the weekend
with high pressure likely keeping the area mostly dry.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
Short Term...Valley fog expected thru sunrise this
morning...likely only affecting LEB. Then widespread VFR into
Tue. Southwest breeze tonight may preclude fog at any TAF sites.
Late Tue as the cold front approaches and SHRA become more
likely some areas of MVFR will be possible...especially across
northern portions of the forecast area.

Long Term...A cold front will bring RA to all sites Tuesday
night- Wednesday morning along with lower ceilings and
restrictions. Conditions improve later Wednesday with NW flow,
although MVFR restrictions may linger at KHIE with upslope flow.
Mainly VFR conditions are then likely through the remainder of
the week, although nighttime valley FG will be possible most
nights.

&&

.MARINE...
Short Term...High pressure largely in control thru the period
Tue. Southwest winds should keep marine fog mostly over Georges
Basin vs closer to the coast. As the cold front approaches Tue
and the pressure gradient increases locally...winds will begin
to get gusty. Outside of the bays 25 kt will become more
frequent and seas will begin to build. SCA will primarily be
after sunset...but will most likely start during Tue afternoon.

Long Term...Southwesterly wind gusts may approach 30 kts on
Tuesday night ahead of a cold front before becoming
northwesterly on Wednesday behind the front with gusts remaining
around 25-30 kts through Wednesday night. Seas of 1-3 ft can be
expected in the bays with 4-6 ft across the outer waters. Winds
and seas then will likely lower through the remainder of the
week as high pressure builds over the waters.

&&

.CLIMATE...
Temperatures will be high enough to possibly challenge records
the next few days as an anomalously strong 580+dam ridge builds
over the area today. Here are some of the records to watch.

                 Oct 6       Oct 7
Concord         84(1990)    90(1963)
Manchester      82(2007)    82(2005)
Portland        84(1947)    84(1947)
Augusta         78(1963)    83(1990)

&&

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

&&

$$

NEAR TERM...Legro
SHORT TERM...Legro
LONG TERM...Tubbs
AVIATION...Legro/Tubbs
MARINE...Legro/Tubbs