Area Forecast Discussion
Issued by NWS Portland, ME
Issued by NWS Portland, ME
571
FXUS61 KGYX 101816
AFDGYX
Area Forecast Discussion
National Weather Service Gray ME
116 PM EST Mon Nov 10 2025
.SYNOPSIS...
A cold front crosses the area tonight ushering in a much colder
air mass. Tuesday will feature gusty west winds and chances for
snow showers, some may be briefly heavy. A persistent northwest
flow regime will bring chances for snow showers in the
mountains most days while southern areas remain mostly dry into
the end of the week.
&&
.NEAR TERM /THROUGH TONIGHT/...
While temps have slowly rotted their way up into the 40s and
50s...we still remain fairly dammed in today. That is leading to
plenty of low clouds and fog/drizzle at times. But rain is
moving back in from the south as the upper low approaches.
Visible satellite is showing the forecast instability well in
the dry slot...with lots of cumuliform clouds developing. Based
on lightning observations near Cape Cod...I anticipate that some
thunder will be possible around the Midcoast/Penobscot Bay this
afternoon and evening.
Late this evening and overnight the cold front/occlusion will
start mixing thru the forecast area with southwest winds. This
will help to clear out the low clouds and fog and bring an end
to most of the precip. I say most because then we will
transition to a more upslope regime. West southwest winds are
less favorable for this and any significant accumulation of
precip...but I suspect some showers will develop in the terrain.
Temps will also steadily drop in CAA...and rain should change to
snow thru the night.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
By Tue the forecast area will really be under the CAA and winds
will turn more west northwest. Forecast soundings show mixing to
around 25 to 30 prior to noon...so I stayed close to the NBM
forecast for this time period. After noon winds increase aloft
even as the mixing height decreases...so I bumped up gusts in
this window thru sunset. After sunset I am always wary of
increasing winds too much...as we tend to be able to decouple
just enough to avoid the worst of it. That being
said...inversion heights lower to around summit level in the
mtns. This will help to accelerate the winds over the peaks and
model guidance is already hinting at this. I blended in some
hi-res guidance to show the increasing downslope winds
overnight.
As for the precip Tue...the wind direction will be more
favorable for upslope snow showers...so I did adjust PoP up to
likely/categorical in the mtns zones most favorable. However
south of the mtns will be interesting too. Low level lapse rates
become steep during the day. Models even forecast a bit of low
level instability...with 0-3 km CAPE between 50 and 100 J/kg.
The snow growth zone will drop to a favorable
height...overlapping with lift as the upper trof swings thru. So
I am anticipating that some convective snow showers may develop
in the afternoon. It does not look like a solid/broken line kind
of set up...but at least one where scattered cells develop and
sweep east. I have had to blend in some hi-res convective
allowing guidance to get PoP across western Maine south of the
mtns to highlight this threat. But it does look like brief heavy
snow and the accompanying low visibility could be a hazard for
parts of I-95 and I-295 Tue afternoon before sunset.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Pattern Overview: Broad troughing overhead mid-week transitions
to an upper low that gets blocked over the Gulf of St. Lawrence
by an Atlantic ridge in the late week time frame. Several waves
rotate around this upper low and through our area, but a lack
of forcing at the surface may lead to no more than light showers
at times. Models are coming into better agreement on the
blocking ridge breaking down over the weekend.
Impacts and Key Messages:
* No significant weather impacts expected at this time
Details: Wednesday: Warm air advection may allow for some light
snow showers in western New Hampshire early Wednesday morning.
Otherwise the cyclonic flow is going to lead to a cloudy, but
mostly dry day. High temperatures look to end up in the mid- to
upper 30s to the north, and in the low to mid-40s south of the
mountains. A fairly tight gradient to low pressure just off to
our north makes for a breezy southwest wind, around 15-25 mph.
Some clearing south of the mountains, and the return of upslope
showers in the mountains, should be realized as flow aloft turns
northwesterly once again Wednesday night. Low temperatures drop
into the mid- to upper 20s in the north, and into the low to
mid-30s to the south.
Thursday and Friday: Northwest flow continues Thursday as the
area remains under the influence of cyclonic flow due to a ridge
in the central Atlantic beginning to block up the pattern.
Upslope snow showers will continue with GFS Froude numbers
suggesting a period of critical flow in the afternoon. This
would allow for a few flakes to make it into the foothills and
maybe even down to the coast, but high temperatures in the mid-
to upper 40s and a deep warm layer evident on Bufkit soundings,
mean these probably melt and end up as sprinkles. Low to mid-40s
and a shallower warm layer in the foothills make that the
better location to see some flakes. High temperatures in the
north look to top out in the mid-to upper 30s. Low temperatures
Thursday night end up in the 20s areawide. An upper low forms
Friday over the Gulf of St. Lawrence as the the pattern remains
blocked. This leaves us in northwesterly flow with shortwaves
rotating around the low helping to sustain showers in the
mountains, and Froude numbers suggest they will stay there.
Continued cold air advection starts a cooling trend with high
temperatures in the low to mid-40s south of the mountains, and
in the low to mid-30s to the north. Low temperatures bottom out
in the low to mid-20s areawide Friday night.
Saturday-Monday: Global models are in reasonably good agreement
that the Atlantic ridge begins to break down Saturday allowing
the upper low to begin its departure and get the pattern moving
again. Upslope snow showers likely start to taper off as the
trough finally departs and by Sunday models start to suggest
some ridging moving in. How long this ridging lasts is the
current sticking point here at the end of the extended forecast
period, but there is agreement in some sort of a system early
next week so we will be keeping an eye on the trends.
&&
.AVIATION /17Z MONDAY THROUGH FRIDAY/...
Short Term...Widespread IFR or lower conditions continue today
in stratus. This will be the case until later this evening when
southwest winds mix things out behind the cold front. Conditions
should rapidly improve to VFR behind this boundary. The
exception will be the mtns where MVFR upslope CIGs will develop.
On Tue gusty westerly winds are anticipated...with surface gusts
of 25 kt or more at all TAF sites except for HIE where cloud
cover may limit mixing. In addition scattered SHSN are possible
in the afternoon...especially across western Maine. Confidence
is pretty low on occurrence at any individual TAF site however.
Long Term...Widespread MVFR looks likely Wednesday as a weak
disturbance moves through the region, but after that VFR should
prevail, outside of a brief shower, outside of the mountains
through Saturday. Terminals nestled in the mountains like LEB
and HIE, will have higher probabilities of restrictions through
this period as snow showers will be prevalent.
&&
.MARINE...
Short Term...Winds have diminished but as expected seas remain
above 5 ft. That is generally expected to continue thru tonight
and then winds increase again from the southwest turning west on
Tue. Seas will build again and gale force gusts are expected
outside of the bays. I have upgraded the gale watch to a warning
and issued a SCA for the bays starting tonight with the
southwest winds behind the cold front. It will likely be until
that southwest winds kick in that areas of fog remain on the
coastal waters.
Long Term...Westerly gales come to an end early Wednesday
morning, but remain in excess of 25kts through the day, before
falling below Wednesday night. Seas won`t fall below 5ft until
early Thursday morning. Conditions than look to stay below SCA
criteria through the weekend. SCA conditions are then possible
again early next week as a system approaches the region.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Gale Warning from 1 PM Tuesday to 7 AM EST Wednesday for
ANZ150-152-154.
Small Craft Advisory from 2 AM Tuesday to 7 AM EST Wednesday
for ANZ151-153.
&&
$$
NEAR/SHORT TERM...Legro
LONG TERM...Baron