South Portland, Maine 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

205
FXUS61 KGYX 032007
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
407 PM EDT Thu Apr 3 2025

.SYNOPSIS...
Fair weather returns tomorrow as high pressure builds into the
region. Yet another chance of a wintry mix arrives this weekend
as a storm heads through the St. Lawrence River Valley. The
pattern will remain unsettled into early next week.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
With the front passed, most precipitation moves out of the region.
Winds will gradually shift from southwesterlies to northwesterlies
tonight. Residual moisture in the mountains will allow for a few
more showers to develop there this evening. Fog is likely to develop
over the Gulf of Maine, as warm air moves over cold open waters.
Dense, overcast skies overnight will allow for warmer low
temperatures tonight, with temperatures in the 40s.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Tomorrow morning, high pressure arrives and will allow
for clearing skies through the day. Clearing skies will allow
southern New Hampshire and coastal Maine to break into the 50s
tomorrow, with some 60s possible in southern New Hampshire.
Northwesterly flow should allow for cooler high temperatures in the
mountains, with high temperatures in the lower 40s. A system will
arrive from the west, bringing increasing cloudiness over the area
tomorrow night.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Overview: A wave of low pressure will follow exiting high pres
into the Northeast this weekend, bringing another round of rain
and wintry precipitation to the area. This lingers through
Sunday night before high pressure quickly moves through northern
New England into Monday. Another disturbance will move through
the region through early to mid week.

Details: Main focus is on this weekend`s event which appears
likely to include another round of mixed precipitation. Low
pressure will initially glide along a stationary front well to
the south, with overunning precipitation spreading throughout
the forecast area Saturday afternoon.

Surface temps and profile temps will play a role in precip types
for the area. CAD appears to be weak as onshore flow moves over
the coast and interior for a couple hours ahead of precip onset.
This will at least allow surface temps to rise above freezing
for all but the mountains of northern NH and western ME.

Warm layer above the surface will bring the chance for wintry
mix across northern areas. NBM probs are high for both a period
of sleet but also freezing rain where sfc temps stay cooler in
the mountains. Confidence in values and area should improve here
on out, but a lot of current uncertainty revolves around how
far north warm front gets this weekend. With warm sfc temps
leading into the event, would need greater CAA to make ice
accretion greater. Will need to watch QPF Saturday evening and
overnight as accretion rates may be greater then vs. Saturday
evening. Should the warm front successfully push north Sunday,
remaining precip falls as rain.

This exiting system will flush the region as a cold front
arrives. Guidance keeps its movement slow, and this could result
in additional precip w/ another wave traveling northeast. EPS
has been fairly locked on positioning for a number of runs, with
GEFS wavering a bit more. The passage is close enough to
include some inland mention of showers lingering into Monday,
perhaps as light snow.

The active pattern continues as a compact low exits the eastern
Great Lakes into Tuesday. This has slowed somewhat, and phasing
with the complex pushing off the East Coast isn`t as complete.
Precip may be snow on the heels of the exiting cold front, and
may need to watch for the chance of snow squalls Tues afternoon
should lapse rates increase.

&&

.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
Short Term...IFR is expected this afternoon as low stratus and
fog lingers over most of the region. Conditions should improve
tonight, as fog and low level clouds mix out. Mostly cloudy
skies are expected tomorrow morning, though VFR is expected
through the day, as skies gradually clear. Clouds increase
tomorrow night as a storm system arrives from the west.

Long Term...Waves of low pressure brings a period of a wintry
mix late Saturday into Saturday night with rain continuing
through Sunday. Periods of IFR to LIFR will be possible late
Saturday through Sunday. Some improvement is possible Sunday
afternoon before the next system crosses New England Sunday
night into Monday.

&&

.MARINE...
Short Term...SCA winds and seas will continue this afternoon.
Winds will be out of the southwest at 15-30kts, slowly shifting
to westerlies tomorrow morning. Winds will slacken to 8-14kts
tomorrow, with seas around 3-6ft. Tomorrow night, winds shift to
southerlies, with seas lowering to 2-4ft by Saturday morning.

Long Term...Waves of low pressure will track across New England
this weekend with winds and seas approaching SCA thresholds
Saturday night into Sunday. Winds will drop below 25 kts Sunday
night while seas remain elevated into Monday. A cold front will
pass the waters Monday, with a compact area of low pressure
advancing towards the waters from the west Tuesday.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 8 AM EDT Friday for ANZ150>154.

&&

$$


NEAR TERM...Palmer
SHORT TERM...Palmer
LONG TERM...Cornwell