South Portland, Maine 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

755
FXUS61 KGYX 041638
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1138 AM EST Tue Mar 4 2025

.SYNOPSIS...
Southwesterly winds will bring in much warmer air today and
allow high temperatures to climb into the 40s for most areas. It
looks to remain mild right through Thursday although that will
come with the cost of some rain and gusty winds late Wednesday
into Thursday. Rainfall amounts will generally be around one
half to one and a half inches but it will take more than that to
really hurt the snow pack across the region. Cooler conditions
will return to the Northeast late in the week and into the
weekend as it remains breezy and unsettled.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

11:35am Update... Refreshed temps based on trends so far this
morning. Temps are quickly warming into the upper 30s to low 40s
where sun is break out, but holding in the low 30s where the
clouds remain thicker. Expecting this trend to continue through
the day, with southeast New Hampshire likely to be the warm
spot as temps warm into the upper 40s. Otherwise, the forecast
remain on track at this point.

Update...Minor changes to reflect latest observational trends.

Previous discussion...Warm front is trying to lift thru the
forecast area this morning. Mid level cloud cover is forming
along and north of the boundary. Much of the radar returns are
virga currently with dry near surface layer still present...but
a couple of snow showers are possible on the highest peaks. The
cloud cover will determine just how warm it gets today...as any
breaks in overcast will allow temps to climb well into the 40s.

Late in the day another surge of WAA will lead to an increase in
shower activity...especially near the front. By this time it
should have pushed farther into the mtns...and the highest PoP
is currently in that area. As daytime heating wanes it may be
possible to squeeze out some light snow accumulations across the
northern zones.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
Precip will taper off at some point overnight...but with plenty
of clouds and mild temps aloft...it should stay well above
normal for low temps.

Wed will see another strong push of WAA on the nose of a
developing southerly LLJ. Again the concentration of precip will
be focused in the mtns. The heaviest precip rates likely hold
off until Thu...but steady light to moderate rain is probable
in the mtns and foothills. There may be a narrow zone of
potential freezing rain...mainly around 1500 ft...where a thin
layer of colder and drier air hangs on for a time. Given the
positioning of high pressure...this should be short lived. I
have also opted for blending in hi-res temp guidance to show
colder air hanging on longer. While it will still be above
freezing...I am hesitant to go into the 50s just knowing how
difficult it can be to scour out low level cold around these
parts.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
05Z Long Term Forecast Update... Latest ensemble and
deterministic based guidance continues to be in good agreement
for an area of low pressure within a negatively tilted H5 trof
axis to bring a widespread moderate rainfall to the region
Wednesday night into Thursday. Rainfall amounts of generally up
to 1" is currently expected with locally higher amounts in the
southeastern slopes of the White Mountains. Behind this system,
cooler weather will return with showers of rain and snow at
times.

Previously...
Overview...

Low pressure moves through the Great Lakes and Saint Lawrence
Valley Wednesday through Thursday. A trough then lingers across
the Northeast through the weekend as high pressure gradually
noses in from the west at the surface through early next week.

Details...
The steadiest rain moves through during the overnight hours on
Wednesday, with more scattered showers and shorter periods of
rain likely through the day on Thursday. Overall rainfall
amounts generally look to be in the 0.75-1.25 inch range, with
some locally higher amounts across the higher terrain.

The low tracks through the Saint Lawrence on Thursday, with a
cold front passing through late in the day. Much of Thursday
will be spent in the warm sector of the system, with highs
ranging from the low 40s across the north where the cold front
moves through earlier, to the mid 50s across southeast New
Hampshire where a few breaks of sunshine are possible through
the day.

With the cold deep snow pack across most of the region, the
majority of the snowpack is expected to survive the event.
Southern and coastal locations are likely to the most snowpack
loss, but also see less rainfall. The higher terrain is likely
see more rainfall, but less snowpack loss. So areal flooding is
still not expected, but river rises, ice break up, and ice jams
remain possible. With the warm temperatures on Thursday, the
possible ice movement and ice jams would most likely occur on
Thursday if they were to come to fruition.

The low continues to deepen across the Canadian Maritimes on
Friday, bringing a deepening trough across the Northeast. Gusty
winds are likely to follow the system during the day on Friday.
Weak disturbances transit through the trough through the
weekend, bringing occasional rain and snow showers, mainly to
northern locations. Relatively cooler air returns during this
timeframe, but a cool airmass is not expected as temps mostly
return to near normal into early next week.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Short Term...Widespread VFR conditions this morning with local
MVFR CIGs in the mtns as a warm front slowly lifts thru the
region. Pockets of MVFR conditions in snow and rain showers will
remain possible this afternoon and evening. Late tonight and
thru Wed the cloud cover will gradually lower and thicken. Areas
of IFR or lower CIGs will develop over much of the area...though
the best chances for precip will largely be confined to the
mtns. Late in the period increasing southerly winds may lead to
LLWS...especially near the coast.

Long Term...IFR to LIFR conditions are likely at all terminals
Wednesday through Wednesday night with low ceilings, fog, and
periods of rain. Gradual improvement is expected on Thursday
with scattered showers, with southern terminals most likely to
return to MVFR and VFR conditions. VFR then returns Thursday
night, with MVFR ceilings more likely at HIE with upslope
conditions. Northwesterly wind gusts of around 30- 35kt are
likely on Friday, with VFR likely at most terminals, and MVFR
more likely at HIE. Mainly VFR with brief periods of MVFR
prevail through the weekend, with westerly wind gusts around
25kt on Saturday

&&

.MARINE...
Short Term...As high pressure slides east southwesterly winds
will increase across the waters today behind a warm front.
Outside of the bays SCA conditions are likely today. Winds and
seas will diminish as the strongest winds aloft move east...but
southerly winds will start to increase ahead of an approaching
cold front late Wed into Thu. Gale force wind gusts likely hold
off until Thu...but strong SCA conditions are expected later in
the day Wed.

Long Term...A deepening low pressure system tracks west of the
waters Wednesday through Thursday. Southerly gales are possible
with this system Wednesday night through Thursday morning.
Westerly gales are then possible on Friday as the low deepens
across Atlantic Canada. The low then only slowly moves away
through the weekend.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 4 AM EST Wednesday for ANZ150-152-
     154.
     Gale Watch from Wednesday evening through Thursday morning for
     ANZ150>154.

&&

$$


NEAR TERM...Clair/Legro
SHORT TERM...Legro
LONG TERM...Clair/Tubbs