Topsham, Maine 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

494
FXUS61 KGYX 180734
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
234 AM EST Sat Jan 18 2025

.SYNOPSIS...
A cold front will cross the area late afternoon into tonight.
Rain and snow will move through ahead of the front, with snow
accumulating a few inches in the mountains. Another wave forms
along the front and will track northeastward towards the Gulf of
Maine Sunday night. Snow will spread into the area to the
northwest of the track. Moderate accumulations are possible.
Then Arctic air pours into the country and lingers through
midweek.

&&

.NEAR TERM /THROUGH TONIGHT/...
A cold front will approach from the west with a weak area of low
pressure forcing along a weak warm front over New England today.
This setup should allow on of the warmer day we`ve had in
awhile, with highs around 40s on the coast and across the south.
20s remain in the mountains. Forcing for ascent increase this
afternoon with showers or light rain moving in southern zones
around or not long after midday. These will spread northeastward
during the afternoon hours. The precipitation type is expected
to be light snow in the mountains (mix in the mountain valleys).
The precipitation quickly comes to an end this evening.
Anywhere between 1 and 4 inches of snow will be possible in the
mountains depending on elevation. If the skies clear out quick
enough in the wake of the snow and rain, slippery spots will be
possible area-wide tonight as temperatures fall into the 20s.

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
Low pressure is expected to form well to our south along the
cold front that passes through here Saturday evening. The low
will quickly move northeastward Sunday. This system will be
different than today`s because the column will be colder and
precipitation type should be all snow. The question is how much
for such a quick overrunning system?

Isentropic lift will be quite strong for several hours Sunday
evening probably allowing for a period of moderate to locally
heavy snow with decent ratios with possible . However, there
are still plenty of guidance differences about where the best
forcing will set up and how much QPF there will really be.

The synoptic setup (pattern recognition) calls for a mid to
high end advisory event to perhaps a low end warning event in
some areas. Basically a 3 to 7 inch storm. Farther inland, in
the mountains the winter storm warning criteria is 8" and that
may be too hard to yeshiva on a widespread basis. With that
said, and with collab from surrounding offices and WPC, will go
with a marginal winter storm watch for southern NH and portions
of central NH as well as the coastal plain of ME. This can be
adjusted farther inland if need be, or conversely, be dropped to
advisories if it looks like a weaker event is forthcoming. This
will mainly be for Sunday night when the heaviest snow is
expected to occur. The vast majority of the precipitation
should be gone by 12z Monday.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Monday will see the colder air begin to work in but the coldest
air will shift in for Tue-Wed.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
Short Term...Clouds will thicken and lower thru today...and
eventually low-end MVFR to IFR conditions are expected as
precip moves into the area. A period of LLWS is also
possible. IFR conditions are expected to continue into Sat
evening when winds shift westerly and VFR returns south of the
mtns.

Long Term...IFR or lowers expected late Sunday and Sunday night
in SN, but should improve to VFR Mon morning. Then mainly VFR
though Wed, although KHIE may see some restrictions in upslope
conds.

&&

.MARINE...
Short Term...SCA conditions will develop this AM...but gale
force gusts outside of the bays likely thru this evening. Winds
and seas will gradually diminish after midnight.

Long Term...SCA conditions likely Sun night through Tue with
light freezing spray increasing on Monday and continuing into
mid-week.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Winter Storm Watch from Sunday afternoon through Monday
     morning for MEZ014-018>028.
NH...Winter Storm Watch from Sunday afternoon through Monday
     morning for NHZ005>015.
MARINE...Gale Warning from 10 AM this morning to 10 PM EST this evening
     for ANZ150-152-154.
     Small Craft Advisory from 7 AM this morning to 1 AM EST Sunday
     for ANZ151-153.

&&

$$


NEAR TERM...Ekster
SHORT TERM...Ekster
LONG TERM...Cempa