Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 142257

Area Forecast Discussion
National Weather Service Gray ME
657 PM EDT Wed Mar 14 2018

Despite the worst of the storm being well to our northeast, the
region remains under the influence of upper level low pressure.
This is continuing on and off light snow over much of the area.
That will pass this evening and overnight, and light
accumulations are possible across New Hampshire and western
Maine, and moderate accumulations possible in the mountains. This
will gradually dry out overnight, and transition to snow
showers in the mountains that linger into Friday. High pressure
takes control for the weekend and fair but cool weather is


Have updated the forecast based on latest conditions. Still
seeing a decent coverage of snow showers this afternoon, though
the intensity and coverage should wane this evening outside of
the mountains where upslope conditions favor continued showers.
Changed weather type from snow to snow showers to reflect the
spotty and brief nature of most of this activity. Since most
areas will not see more than an inch from this activity tonight,
have decided to drop the Winter Weather Advisories. Most of the
Winter Storm Warnings remain in place over the northern part of
the area where more persistent showers could bring several more
inches of snow mainly in the higher elevations. Have also
lowered forecast lows tonight for some areas. Clouds will keep
things from radiating well, but the deep snow pack should be
enough to bring surface temperatures below freezing area wide,
likely into the 20s. Any areas that break out of the clouds
could drop further.

Tonight will feature a transfer from a synoptically driven
snowfall event to more of an upslope event. Plenty of low level
moisture, increasing west to northwest winds and the positioning
of an upper level low overhead will allow for accumulating
snows to continue. Winter storm warnings will remain in effect
over the northern mountains. Elevation will play a role with the
highest snowfall totals along areas above 1500 feet.

Advisories will border the mountains where the foothills will
receive accumulating snow as well. Further to the east, winter
weather advisories will remain in effect over portions of
interior southern Maine until 8 pm.

Elsewhere, expect at least scattered snow showers overnight.
There is also a possibility of a snow squall or two, mainly
over northern areas.

Ptype: There could be some rain mixing in over the Midcoast
region through early this evening. Temperatures do not cool off
much tonight with overnight lows mainly in the 20s.


Have updated Thursday high temperatures to lower the forecast a
few degrees. MOS forecasts seem too high given the expected
presence of cold core upper low affecting the region and
continued deep snow pack. This was the case for much of last
week as well when MOS forecasts were frequently 2-5 degrees too
warm. 925MB temperatures indicate that sea level temps would
reach about 42 degrees in full mixing. Given expected cloud
cover, showers, and heat loss due to melting of the fresh snow
pack, it should be pretty tough to reach 40 degrees.

A brief period of ridging aloft is expected over southern areas
on Thursday, possibly bringing some sunshine to the downslope
areas of southern New Hampshire and Maine. This will allow
portions of the region to warm to 40 degrees or higher during
the afternoon.

Otherwise, expect snow showers to continue in the mountains.
An upper level trough will allow for accumulating snow to
continue in the mountains right through Thursday night.


Outside the flowers are blooming and birds are chirping.
Somewhere. But not meteorological spring has yet to
evict winter from the area.

Upper low will be E of the area by Fri...leaving the region
under Wly...moist low level flow. Upslope snow showers will
continue thru the day...gradually scattering out into the

Surface ridging begins to nose into the region to start the
weekend...gradually exerting more influence into early next
week. It will be seasonably H8 temps pushing -20 C
spill into Nrn zones. Temps should stay mainly in the 30s...with
teens and colder overnight.

Attention then turns to model guidance is in pretty
good agreement at this long range for more precip. Trofing off
the West Coast is forecast to eject into the central CONUS and
initiate cyclogenesis. Though there are some differences in
evolution...there is broad consensus for likely PoP Tue into
Wed. There is significant spread in ensemble this
is still 7 days this is a low confidence
forecast...especially with any details. At this time
deterministic and ensemble guidance is cold enough for
snow...but at this time it could just as easily trend warm and
W...or out to sea.


Short Term /through Thursday/...Areas of MVFR and locally IFR
conditions over northern areas right through Thursday. Mainly
VFR conditions over the southern downslope regions.

Long Term...Generally VFR conditions expected thru the weekend.
The exception will be Fri...and Wly upslope flow continues under
upper low pressure. HIE may see SHSN and local IFR conditions in
the vicinity...though by Fri more of the TEMPO variety.


Short Term...Have issued gales for the outer waters for tonight
as winds continue to gust to 35 kt+. SCAs have been posted for
the bays. Seas to gradually subside with time.

Long Term...Wly flow lingering into Fri will likely keep SCA
conditions going outside the bays. High pressure will slowly
build in for early next week...allowing winds and seas to
gradually diminish.


ME...Winter Storm Warning until 6 AM EDT Thursday for MEZ007>009.
NH...Winter Storm Warning until 6 AM EDT Thursday for NHZ001>003.
     Winter Weather Advisory until 6 AM EDT Thursday for NHZ004.
MARINE...Small Craft Advisory until 6 AM EDT Thursday for ANZ151-153.
     Gale Warning until 6 AM EDT Thursday for ANZ150-152-154.



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