NWS Gray, Maine Area Forecast Discussion
847
FXUS61 KGYX 161418
AFDGYX
Area Forecast Discussion
National Weather Service Gray ME
1018 AM EDT Mon Mar 16 2026
.WHAT HAS CHANGED...
Quick update to cancel the Winter Weather Advisory a little bit
early. While some of the highest peaks could still see some
patchy freezing rain, road temperatures have generally warmed
above freezing.
&&
.KEY MESSAGES...
1. A brief bout of light freezing rain early this morning may
bring about slippery travel across the north and down into the
Monadnock region through the morning commute. Impacts are mainly
expected at higher elevations.
2. A potent low pressure system will bring heavy rain and
gusty winds to most of the forecast area today through Tuesday
morning. Have expanded the wind advisory to some zones primarily
for this evening. Some localized flooding is possible as a
result of significant runoff and snowmelt. The risk of flooding
as a result of ice jams remains low, but non- zero as some ice
does remain in the mountains and northern basins.
3. Colder air briefly returns midweek with quieter weather
before temperatures trend back toward normal for the second half
of the week.
&&
.DISCUSSION...
KEY MESSAGE 1 DESCRIPTION...
Temperatures are expected to bottom out below freezing
in the north, and in the higher elevations of the white mountains
and Monadnock region. Weak cold air damming likely allows a period
of light freezing rain to occur this morning, before the warm front
sweeps through and changes it over to plain rain by the afternoon.
Amounts look light, a tenth of an inch or less, and should be mainly
confined to the higher elevations. A Winter Weather Advisory is in
effect from 3 AM to noon for potentially slick travel.
KEY MESSAGE 2 DESCRIPTION...
Not much has changed with regards to timing as precipitation is
expected to start moving into the area around 3 to 4 am. As
mentioned above it may start as a brief period of freezing rain
for the higher elevations, but for most it will be plain rain.
It starts light, but with anomalous PWATs, and CAMs continuing
to suggest a couple hundred joules of MUCAPE present, it won`t
take long for heavier rain to develop. Impacts with this first
round likely come in the form of ponding on roadways and low
visibilities as models continue to target the I-95 corridor and
the Midcoast with higher rainfall totals. There remains good
agreement on a lull of sorts for a good part of the afternoon as
activity becomes more showery, but forecast soundings suggest
any break in rain will be filled with fog and/or drizzle as
moisture transport into the region increases. The second round
of rain arrives Monday evening and crosses through the overnight
period as a cold front swings through. As with the first round,
instability and anomalous PWATs (that will be even higher at
this point) will allow for it to be heavy at times. WPC has put
us in a Marginal ERO, meaning the flash flood risk is non-zero,
however the progressive nature of these rounds of rains should
help to keep this risk very low. That being said don`t be
surprised if you see some nuisance flooding in urban and low
lying areas. Runoff from excessive rainfall in the mountains
poses a minor riverine flooding risk along with warm
temperatures allowing for any remaining ice to shift and move as
well. For more details on these risks see the hydrology section
below. Confidence in rainfall totals around 1-2 inches remains
high, with confidence increasing in locally higher totals as
high as 3" on the Midcoast and in the White Mountains.
Another concerning aspect of this system is the winds, mainly
because of how much uncertainty still surrounds them. During the
morning hours 850 mb winds increase to 50-60 knots with
forecast soundings continuing to suggest a strong inversion
preventing efficient mixing. However, the pressure gradient
alone should be good enough for us to see gusts 20-25 mph during
the day. The more concerning period is the evening as the low
level jet increases. Some solutions are now suggesting winds as
high as 100 knots just off the deck over the coastal plain.
Again, forecast soundings hold on to the inversion but the
concern comes in those times where enhanced precipitation may
allow for higher gusts to mix down, with the question being how
much momentum will be behind them. The Wind Advisory highlights
the areas of highest confidence for frequent 40-50 mph gusts,
but the Midcoast could see gusts 55-60+ with the push Monday
evening. Confidence isn`t high enough to upgrade to a High Wind
Warning anywhere at the moment, and if it is going to occur with
convective activity we could handle it with short fuse warnings
as well. The other area to watch will be on the north sides of
the mountains as downslope enhancement of the already strong
winds is possible. The power outage threat is limited across
most of the area but is locally elevated within the Wind
Advisory.
Lastly, a quick note on coastal flooding as I am sure the
strong onshore flow has brought this to some folks minds. This
is not a primary concern with this system. The astronomical tide
is only around 9 feet at both of Monday`s high tide cycles and
it looks like the peak of the winds is only going to be occuring
at the lower of the two which is Monday night. Surge models are
currently forecasting around a foot and change of surge which
would not even bring us to action, and therefore no products
seem necessary at this time. As always, we will keep an eye on
it just in case.
Precipitation begins tapering off Tuesday morning with cooler
air quickly filling in behind the front. High temperatures top
out in the mid to upper 30s north of the mountains and in the
40s to the south. A tight pressure gradient and efficient mixing
is going to allow for west/southwesterly gusts 30-35 mph to
continue through the day which will make it feel a bit colder.
KEY MESSAGE 3 DESCRIPTION...
A period of more tranquil but cold weather is expected after
the departure of the aforementioned system. Northwesterly winds
and very cold temperatures will allow for a bitterly cold
morning on Wednesday. Wind chills are expected to be in the
single digits below zero in the mountains, with single-digits
above elsewhere.
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, though models remain very uncertain on
timing and storm track.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
Through 12Z Tuesday...IFR conditions will continue through much
of the day under low ceilings and periodic heavy rain. Scattered
LIFR conditions will be possible through the day as well but
there could be some breaks in precipitation this afternoon.
Enhanced low- level wind shear around 35-40 kts will also be
likely at almost all sites starting late this evening. High
confidence in widespread IFR/LIFR cigs continuing as a second
round of rain arrives after 00Z Tuesday. LLWS continues with
many terminals seeing an increase to 45-50kts, with strong SE to
S surface gusts, 30-40 kts, along at least coastal terminals.
Outlook...
Overnight Monday-Tuesday: Precipitation will begin to taper off
early Tuesday morning with conditions slowly improving to VFR
at most terminals by Tuesday afternoon. Gusty winds 30-35 kts
will persist through the day.
Wedenesday-Friday: VFR expected, with a slight chance of lower CIGs
at HIE due to a stray snow shower on Friday.
Saturday: VFR expected, though restrictions can not be ruled out for
light rain and snow.
&&
.MARINE...
Onshore flow will increase through the day with frequent gales
likely by early this morning and frequent storm force gusts
likely by tonight. Storm force gusts taper off early Tuesday
morning with gales tapering off by Tuesday afternoon. Winds
gusts 25-30 kts continue through Tuesday evening. This wind will
build wave heights to a peak of 12-15ft early Tuesday morning,
and then they will very slowly start to fall through the day
Tuesday. This strong system will bring heavy rain an possibly
thunder to the waters through tonight.
Seas of 8-12ft and westerly gales are expected Tuesday night.
Conditions start to improve by Wednesday morning, with sub-SCA level
westerlies and 6-10ft seas expected by then. Sub-SCA winds and seas
of 3-7ft are expected through the remainder of the week.
&&
.HYDROLOGY...
A Flood Watch has been issued for today into Tuesday as an
anomalously moist airmass interacts with the ripe snowpack
across the area. The main focus is on excessive runoff when the
heaviest rainfall tonight coincides with rapid melt, leading to
dramatic rises in area streams and rivers. There is high
confidence that we will see 1 to 2 inches of rain, with some
ensembles targeting the White Mountains and the Midcoast of
Maine with over 3 inches. Snowmelt will be limited initially due
to cold air damming in the mountains, but this will erode late
this morning as moisture surges north under a powerful 70 to
90+ knot low- level jet. Given the anamolous moisture, expected
PWATs should be in the 1.2 to 1.4 inch range (near the 99th
percentile for mid- March). Thus, the environment should be
primed for heavy rainfall. The late moisture surge tonight will
be the real nudge needed to push water out of the already
ripened snowpack. The expected snowmelt water loss of 1 to 1.5
inches will mostly occur between this evening and early Tuesday
morning, about 6 to 12 hours. The coinciding of heaviest
rainfall with rapid snowmelt will lead to swift rises on small
streams and rivers. The mainstream rivers have a lot of channel
capacity due to lingering drought, but more confined channels
in the mountains or small streams could easily be overwhelmed
resulting in localized minor flooding. Deep frost will limit
infiltration, so for some areas the sheer volume of water could
overwhelm culverts, low-lying areas, and low-water crossings.
Expect urban street flooding and drainage issues. While many
southern rivers are ice-free, some ice remains in the mountains
and northern basins. There remains a non-zero risk for
mechanical break-up and unpredictable jams as flows increase.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Flood Watch from 2 PM EDT this afternoon through Tuesday
afternoon for MEZ007>009-012>014-018>028-033.
Wind Advisory from 8 PM this evening to 8 AM EDT Tuesday for
MEZ014-021>028.
Wind Advisory from 8 PM this evening to 5 AM EDT Tuesday for
MEZ018>020.
NH...Flood Watch from 2 PM EDT this afternoon through Tuesday
afternoon for NHZ001>015.
Wind Advisory from 8 PM this evening to 8 AM EDT Tuesday for
NHZ014.
Wind Advisory from 8 PM this evening to 5 AM EDT Tuesday for
NHZ007>013-015.
MARINE...Storm Warning from 8 PM this evening to 8 AM EDT Tuesday for
ANZ150>152-154.
Gale Warning until 8 AM EDT Tuesday for ANZ153.
&&
$$
DISCUSSION...Hargrove/Ekster/Baron/Palmer
NWS GYX Office Area Forecast Discussion
