South Portland, Maine 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

516
FXUS61 KGYX 030340
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1140 PM EDT Wed Apr 2 2025

.SYNOPSIS...
A warm front will lift into New England tonight bringing a
period of snow to a wintry mix that will change to rain
Thursday. High pressure builds in Friday for fair weather. Low
pressure tracking into the St Lawrence Valley will bring another
round of wintry precipitation changing to rain late Saturday
into Sunday. Additional waves of low pressure will track along
a frontal boundary that will be near southern New England early
next week.

&&

.NEAR TERM /THROUGH THURSDAY/...
1130 PM Update... Minor changes to reflect latest observational
trends. Mixed wintry precipitation is being reported at this
hour across southern NH with some light snow now beginning
further to the north and east. The theme for the overnight will
be for a transition to a wintry mix with slippery travel
conditions possible before a changeover to plain rain for most
locations south of the foothills by early Thursday morning.

Previously...
615 PM Update... Surface observations early this evening
continue to show that the lower to mid-levels remain quite dry
with dew point depressions in some cases of 30+ degrees.
ASOS/AWOS reports indicate that precipitation is just now
reaching the ground over portions of central NY state with the
remaining radar echoes closer to our area simply being virga.
Based on these observational trends and latest hi-res guidance
went ahead and pushed back the start time of the winter weather
advisory to 11PM this evening, except south of Coos county in NH
where it will begin at the original start time of 8PM.

PoPs were also delayed some, particularly across ME where column
saturation and strong forcing for ascent does not look to arrive
until late evening. Otherwise, just made some minor adjustments
to temperatures and sky cover.

Previously...
Tonight, a low moves eastward, bringing some
precipitation into the region. An isothermic environment tonight
will allow for most precipitation to start as snow. Overnight,
southerly winds at low levels will break the isothermic layer
allowing for a gradual changeover to sleet and freezing rain
overnight.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH 6 PM THURSDAY/...
Tomorrow morning, interior locations are the most likely to see
mixed precipitation into the morning commute, but mixed
precipitation will transition to rain from south to north. Once
transitioned to rain, temperatures will likely rise, as warm
air works its way down to the surface tomorrow afternoon. High
temperatures are likely to be in the upper 50s and 60s in the
Connecticut River Valley and southern New Hampshire, with
mid-40s in Maine and elsewhere.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
04Z Long Term Update... Latest guidance continues to be in good
agreement for a period of precipitation from a wave of low
pressure to impact the area Saturday afternoon through part of
Sunday. Temperature profiles look to support a period of mixed
wintry precipitation initially across the foothills and points
north with primarily rain likely further to the south and east.
Did continue to incorporate this mixed precipitation in the
weather grids. After this system mainly dry and cool
temperatures look to prevail.

Previously...
Overview: High pressure will build in Friday for
fair weather. A period of active weather follows as wave of low
pressure track along a frontal zone that slowly shifts south of
the area early next week. The first wave will bring widespread
wintry precipitation late Saturday into Sunday. Thermal profiles
with this system will support snow/wintry mix across the
interior early Saturday night with a transition to rain from SW
to NE Sunday morning. There may be a lull in precipitation
Sunday afternoon before the next wave of low pressure tracks
across southern New England Sunday night. Chances for
precipitation drop off Monday while global models suggest
additional systems will be possible towards the middle of next
week with a trough approaching the Northeast.

Impacts: Snow to a wintry mix could bring slick travel across
northern areas late Saturday through Saturday night.

Details: Drier air will work into the area Thursday night into
Friday on NW flow. A NW gradient will remain over area Friday as
high pressure builds in from west with wind gusts approaching 25
mph. Skies will turn mostly sunny by Friday afternoon with highs
ranging from the mid 40s north to mid 60s across southern NH. High
pressure will crest over the area Friday night allowing for lows to
drop into the low 20s to low 30s from north to south.

A wave of low pressure will track from the Ohio Valley towards the
St Lawrence Valley late Saturday into Sunday with precipitation
likely overspreading the area by Saturday afternoon. A dry airmass
in place will allow for some wet bulbing leading precipitation
starting as snow across the north and a mix of rain and snow
south of the mountains. Warm air advection will continue through
Saturday night with precipitation changing to a wintry mix
across the north and rain across the south by Sunday morning.
Temperatures will eventually rise above freezing across all
areas after day break Sunday with rain becoming the dominant
precipitation type. Precipitation will taper off Sunday
afternoon before the next wave of low pressure approaches Sunday
night.

The next wave of low pressure will bring chances for rain south
of the mountains and a mix of rain and snow across the north
Sunday night into Monday. Colder air attempts to work into the
region Monday night that may allow for snow showers south of the
mountains.

&&

.AVIATION /04Z THURSDAY THROUGH MONDAY/...
Short Term...VFR expected this evening, with increasing
cloudiness. IFR expected overnight and LIFR expected through
most of the day tomorrow as a system brings snow, sleet,
freezing rain and rain to the region. Conditions start to
recover tomorrow evening, though low stratus may linger on the
coast. VFR returns to the region Friday morning.

Long Term...Lingering MVFR cigs Thursday night will transition
to VFR Friday into Saturday morning. Waves of low pressure
brings a brief period of a wintry mix late Saturday changing to
rain 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...Southerly winds of 7-12kts expected this afternoon with 2-4ft
seas. Winds and seas increase overnight as a low arrives from
the west. Winds and seas pick up to SCA Thresholds tomorrow
morning, with winds gradually shifting from southerly to
southwesterly by the end of the day tomorrow.

Long Term...Winds shift out of the west Thursday night with gusts to 25
kts until Friday morning. High pressure builds over the waters
Friday with winds and seas likely dropping below SCA thresholds by
Friday afternoon. 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.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Winter Weather Advisory until noon EDT Thursday for MEZ007>009-
     012>014.
     Winter Weather Advisory until 10 AM EDT Thursday for
     MEZ018>022-033.
NH...Winter Weather Advisory until noon EDT Thursday for NHZ001-002-
     004.
     Winter Weather Advisory until 10 AM EDT Thursday for NHZ003-
     005>011-015.
MARINE...Small Craft Advisory from 5 AM to 8 PM EDT Thursday for
     ANZ150>152-154.
     Small Craft Advisory from 5 AM to noon EDT Thursday for ANZ153.

&&

$$

NEAR TERM...Tubbs
SHORT TERM...Palmer
LONG TERM...Schroeter/Tubbs