NWS Gray, Maine Area Forecast Discussion
501
FXUS61 KGYX 150546
AFDGYX
Area Forecast Discussion
National Weather Service Gray ME
146 AM EDT Sun Mar 15 2026
.WHAT HAS CHANGED...
Have issued winter weather advisories for tonight into Monday
morning for western NH northward through the western ME
mountains for light freezing rain, mainly at high elevations.
Have also issued storm watches for the outer waters and Pen Bay
with a gale watch for Casco Bay, mainly for later Monday and
Monday night.
&&
.KEY MESSAGES...
1. A potent low pressure system will bring some locally heavy
rain and gusty winds to most of the forecast area early Monday
morning through Tuesday morning. Some localized flooding is
possible as ice jams loosen and the remaining snow melts.
2. Slippery conditions possible late tonight and Monday morning
in the winter weather advisory area as light freezing rain is
expected, mainly at higher elevations.
3. Gusty winds remain behind the departing system Tuesday, with
otherwise little to no impactful weather through mid-week. Some
guidance suggests the next chance for widespread precipitation
around the Saturday timeframe, but there remains a wide envelop
of outcomes.
&&
.DISCUSSION...
KEY MESSAGE 1 DESCRIPTION...
As 00Z data continues to be received models remain in
reasonably good agreement on most aspects of Monday`s storm.
Rain looks to just be beginning in southwestern New Hampshire
around or after midnight and overspreading the area through the
rest of the night and Monday morning. At this point ensembles
suggest PWATS are around 0.75 to 1" which suggests some locally
heavy rain is possible, particularly in southern New Hampshire
where the higher values are present and also eastern slopes of
the White Mountains. The CAMs also agree there could be some
instability here as well leading to convectively enhanced
precipitation and maybe a period of thunder.
Activity looks to become more showery and drizzly Monday
afternoon so some locations may see a lull (or a few lulls).
However, a strong low level jet continues to transport deep
moisture into the area so showers are going to be able to put
down some water with PWATs rising into the 1.25 to 1.40" range.
The afternoon is also when winds gusts may ramp up, but this is
probably the most uncertain aspect of this storm. There is going
to be a very strong low level jet moving overhead (around 90
kts at its peak Monday night), but forecast soundings show a
stout inversion forming and persisting during this time as
well. Models like the NAM and Euro are on the conservative side
keeping gusts generally in the 30-40 mph range which is
reasonable with just the tight pressure gradient that will be
present alone. Models like the HRRR and the GFS are a little
more bullish with 50-60 mph gusts. I feel like the solution is
more of a hybrid, 30-40 mph gusts a good ballpark for what will
likely be frequently observed with the inversion keeping us from
the higher values. However, convective mixing would briefly
negate the effect of the inversion meaning those values of 50-60
mph may be a good estimate for what could be observed briefly.
I could see wind headlines eventually being needed, but
confidence is still too low with the looming inversion
potentially keeping the frequent gusts just below advisory
level. Best chance at wind headlines would likely be the
Midcoast of Maine.
The second slug of rain comes Monday evening as the cold front
approaches. PWATS remain elevated and the NAMNest continues to
suggest enough instability for continued convective enhancement,
so heavy rain remains a factor until the early hours of Tuesday
morning when it begins to taper off. When all is said and done
1-2" still looks like a good estimate for total rainfall with
much of the area expected to fall right in the middle. Ensemble
probabilities are now 90 to near 100% for the majority of the
forecast area to receive over 1". Areas north and west of the
mountains may fall just short as they are less likely to see the
enhanced rainfall. The areas that ensembles continue to target
for greater than 2" are the Midcoast and the White Mountains,
with probabilities still in the 60-70% range. It should be noted
CAMs are targeting the Midcoast as well. Fortunately the
Midcoast should make out just fine. The more concerning area for
2" of rain to fall is the mountains and with the upslope
component, enhancement there is not uncommon. Runoff from this
could bring some of the more sensitive river forecast points
into action or near minor flood stage. The ice jam flooding risk
has decreased a bit with observations showing most rivers have
flushed out their ice, but some is still present especially in
he north so this risk is non-zero and rivers are going to have
to be monitored closely. Confidence is not there yet for any
flood headlines, but as we are able to determine how rivers are
going to react to this runoff those may be needed eventually as
well.
KEY MESSAGE 2 DESCRIPTION...
The antecedent SFC air mass later tonight and early Monday
morning should be cold enough to support light freezing rain
across western and northern NH as well as the western ME
mountains along with portions of the foothills. Have therefore
issued a winter weather advisory for potentially slippery
conditions in these areas later tonight into Monday morning. But
Monday afternoon it will likely warm up enough to allow just
plain rain.
KEY MESSAGE 3 DESCRIPTION...
As the aforementioned system exits the region Tuesday, gusty
northwesterly winds will pick up as a pressure gradient sets up
in between the departing system and incoming high pressure from
the west. In addition, a mid-level trough will engulf the
northeast, allowing for a quick return to winter. Wind chills
look to be in the single digits or colder Wednesday morning as a
light northwesterly breeze presides over air temperatures
ranging from single digits up north to teens along the coast and
south.
High pressure continues through the rest of the week, with
temperatures gradually warming as the mid-level trough makes a
slight realignment to the west. The next chance for
precipitation looks to be next weekend.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
Through 12Z Monday...Westerly winds relax into this morning
with VFR conditions. VFR should prevail through this evening.
Conditions deteriorate overnight tonight as ceilings lower to
MVFR ahead of our next weather system. IFR conditions are
possible as early as 08Z Monday as precipitation begins to enter
the area.
Outlook...
Monday-Monday night: High confidence in widespread IFR cigs as a
storm arrives with RA and FG. LLWS is likely, with strong SE to S
surface gusts along at least coastal terminals.
Tuesday: Cigs should be improving to VFR from MVFR through the
morning. W gusts 30-35 kts through the day.
Wednesday-Thursday: VFR expected, no sig wx.
&&
.MARINE...
Conditions turn fair on the waters today as high pressure
crosses the area. Overnight tonight conditions will quickly
deteriorate as a strong weather system approaches. Easterly
gales are possible by Monday morning, with near storm force
winds possible by Monday night. This will also build wave
heights to 15-18ft at their peak Monday night.
Gale force westerly winds Tuesday morning continue as low
pressure departs from the Gulf of Maine. Abnormally high surf is
expected, with seas of 10-16ft. Seas drop to 8-12ft by the end
of the day. Conditions start to improve by Wednesday morning,
with SCA level westerlies and 6-10ft seas expected by then. SCA
conditions continue through the day Wednesday. Sub-SCA
conditions return for the end of the week as high pressure moves
overhead.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Winter Weather Advisory from 3 AM to noon EDT Monday for
MEZ007>009-012-013.
NH...Winter Weather Advisory from 3 AM to noon EDT Monday for
NHZ001>005-007.
MARINE...Small Craft Advisory until 10 AM EDT this morning for ANZ150-
152-154.
Storm Watch from Monday evening through Tuesday morning for
ANZ150>152-154.
Gale Watch from Monday morning through Tuesday morning for
ANZ153.
&&
$$
DISCUSSION...Ekster/Baron/Palmer
NWS GYX Office Area Forecast Discussion
