Portland, Maine 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

763
FXUS61 KGYX 051027
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
627 AM EDT Sun Apr 5 2026

.WHAT HAS CHANGED...
Have canceled the Winter Weather Advisory for New Hampshire as
temperatures have risen above freezing and the threat for
freezing rain has ended.

&&

.KEY MESSAGES...
1. A cold front will cross the region today and bring rounds of
showers to much of the area, but a wintry mix in the mountains
of New Hampshire and western Maine.

2. This upcoming week is going to be bookended by chances for
precipitation, with warmer temperatures and drier weather in
between

&&

.DISCUSSION...
KEY MESSAGE 1 DESCRIPTION...

Forecast is largely on track as a surface warm front tries to
lift into New England. Still not expecting that to make much
progress into the forecast area. Based on current temps and
dewpoints out there, the Winter Weather Advisories look to be in
the right areas. The arrival of showers and steady moistening
from the marine layer should allow temps to settle near the
current wet bulbs. That may leave some areas south of the mtns
33 and rain, but I do not see too much of a freezing rain threat
outside of the areas already under a headline. Even some of
those locations in the downslope of the White Mtns may see
locally warmer and drier conditions. Thru the morning I
anticipate periods of showers, some of which may be pretty good
downpours, but not really a steady rain. There may also be areas
of fog that develop towards sunrise, especially near the coast.
The best chance for steady rain will be along the advancing
cold front. Ensemble guidance still showing that the majority of
the forecast area is likely to see between 0.25 to 0.5 inches
of liquid, with the higher amounts most likely over northern and
eastern zones. The front will sweep out any remaining low level
fog/clouds, but some upslope snow showers may linger in the
mtns into Mon. Models do not have a great handle on that, so I
have bumped PoP up to reflect that chance.

KEY MESSAGE 2 DESCRIPTION...

Tuesday is going to be the first widespread chances for
precipitation next week as we get low pressure moving through
the region on a cold frontal boundary, along with a 500 mb
trough overhead. The timing of precipitation looks to follow the
cold air filtering into the region so light snow is expected to
be the dominant precipitation type. Hi-res guidance suggests
more in the way of showers with little in the way of
accumulation for the areas that see them. The higher peaks could
see an inch or two, but outside of that a dusting to maybe a
half inch at most looks like all we will get out of these. They
move through in the afternoon, and move out before the evening
is through. Temperatures behind the front will bottom out in the
teens pretty much areawide Tuesday night.

High pressure follows with ridging aloft, so we will see
temperatures steadily climb, with drier weather, into the first
part of Saturday with nighttime temperatures generally staying
above freezing as well. The 500 mb pattern switches to mean
troughing on Friday, but high pressure still locked in at the
surface should keep us dry. The next widespread chance for
precipitation then looks to be Saturday as another frontal
boundary moves through. This will be one of the warmer days of
the week with temperatures nearing 60F in most locations, so
this should be rain. As always this time of year we will have to
keep a close eye on how this pattern evolves, particularly
where high pressure sets up, for any potential for mixed
precipitation in northern zones.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
MVFR conditions continue to work into the forecast area from
the south and east. Conditions will continue to gradually
deteriorate over the next few hours. CIGs are expected to lower
across southern NH first, and expand northeastward into western
Maine thru the early morning hours. Some areas of fog may also
develop around sunrise and continue into midday. Periods of
showers are expected thru the day until the cold front crosses
the region. The only real threat of a wintry mix is around HIE,
but gusty, downsloping winds are keeping precip light and temps
warmer locally. By afternoon front/wind shift will be east of
the forecast area and VFR conditions will return to the majority
of the area. The exception will be in the mtns, where MVFR CIGs
hang on and a few upslope rain or snow showers are possible.

Outlook...

Monday: VFR conditions expected.

Monday night: VFR conditions expected

Tuesday: Generally VFR with MVFR or lower conditions expected
in light snow showers during the day.

Tuesday night-Thursday: VFR conditions are expected through
much of next week as we see a period of quiet weather.

&&

.MARINE...
Onshore winds will continue to build seas and gust to marginal
SCA criteria thru morning. There may be a brief lull in which
winds become light, but seas will generally remain at or above 5
ft outside of the bays. This will be the time period when areas
of fog will be most likely. A cold front will cross the waters
during the afternoon and winds will shift sharply to westerly.
These winds may also gust to at or above 25 kt and additional
SCA conditions are anticipated into Mon.

A period of sub-SCA conditions looks likely Monday night
through the day Tuesday, but a period of wind gusts 25-30kts
with bring that to an end Tuesday night as a front crosses the
waters. Wednesday may also feature sub-SCA conditions as high
pressure begins to build over the waters, but the pressure
gradient tightening ramps wind gusts and waves up above SCA
criteria Wednesday night through Thursday night. Waves might be
a little slower to settle than winds, but conditions should
improve on Friday with high pressure still in place. Another
front crosses the waters Saturday with brief SCA conditions
possible.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Winter Weather Advisory until 10 AM EDT this morning for
     MEZ007>009.
NH...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ150-
     152-154.
     Small Craft Advisory until 11 AM EDT this morning for ANZ151-
     153.

&&

$$

DISCUSSION...Baron/Legro/Schroeter