Area Forecast Discussion
Issued by NWS Portland, ME

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS61 KGYX 221329

Area Forecast Discussion
National Weather Service Gray ME
929 AM EDT Thu Mar 22 2018

Low pressure will track east of the Gulf of Maine today, before
moving through the Canadian Maritimes tonight. An upper level
trough of low pressure will cross over northern New England on
Friday and early Saturday. Yet another upper level trough will
cross the region late Saturday and Saturday night. High
pressure will build in from the north Sunday and Monday and will
hold over the area on Tuesday. A warm front will approach the
region from the west Wednesday.


9am update... Have updated the PoPs to try to better reflect the
sharp back edge of the snow. Heavier snow will continue another
few hours few the midcoast, with light snow through the
southwest coast of Maine and southern New Hampshire. The low
center and snow will continue to move east and pull out of the
area this morning.

Have issued SPSs for the morning commute for the coastline and
portions of southern New Hampshire. Expect the snow to continue
through the mid morning hours with 1 to 3 inch accumulations.
The snow will then begin to diminish during the late morning
hours. The snow may hold on an hour or two longer in the
Penobscot bay region.

Prev Disc...
Have updated the forecast based on current conditions and
latest Radar imagery. A band of snow moved onshore from the Gulf
of Maine during the early morning hours. However, dry air in
place has diminished this feature. New bands of snow continue to
rotate around the periphery of our offshore system, so we
expect some snow to survive the trip to the coastline. Will
leave 1 to 3 inches of snow in the forecast, but drop the
remaining winter weather advisories for the coast of Maine.

Otherwise, some tweaks were made for pops today.

Prev Disc...
Plenty of dry air remains in placed over Maine and
New Hampshire, especially over the interior. Dew point
depressions are also inhibiting the potential for snow across
much of the region. Having said that, a band of snow has moved
onshore during the early morning hours with visibilities as low
as one mile reported within it. Will monitor this band as it
continues to move gradually to the northwest.

Most large scale operational models suggest very little in the
way of precipitation this morning. However, will continue to
monitor this mesoscale band and will hold onto the winter
weather advisories for a few more hours along the coast. Will
drop the advisories over much, if not all of New Hampshire. This
band may deposit some light snow over the interior as well.

Either way, the snow should rapidly melt today with forecast
high temperatures in the upper 30s to lower 40s over southern


Cyclonic flow aloft and northwesterly low level winds will allow
for some upslope conditions in the mountains tonight and Friday.
Therefore, expect some scattered snow showers across the higher
terrain. More melting will occur during the day Friday despite
temperatures below normal for this time of the year. Expect
reading to reach 40 degrees in southern and central areas.


Models in fairly good agreement for the end of the week and the
first half of the weekend as an upper trough remains parked over
the area, Looking for variable clouds Friday night with just a
slight chance of snow showers in the mountains. Lows will range
through the 20s.

Any morning sunny breaks Saturday will quickly give way to mostly
cloudy skies as low level moisture and surface trough rotates in
from the northeast, Will see snow showers during the afternoon in
eastern zones. Highs Saturday will range through the 30s to near 40.
Trough will work its way toward the southwest Saturday evening
pushing the chance of snow showers into southwest zones before
ending after midnight. May see some light accumulations during the
late afternoon and evening but should only amount to an inch or less
in most areas. Lows Saturday night will range from the mid teens
north to the mid 20s south.

Clouds will gradually diminish from north to south during the day on
Sunday as high pressure builds in from the north. Highs will top out
below normal ranging from the upper 20s north to the mid 30s south.
Any lingering clouds will gradually clear Sunday evening as high
pressure continues to build in from the north. Clearing skies and
light winds will allow for good radiational cooling with lws ranging
through the teens north and lower to mid 20s south.

Sprawling high pressure will park over the region on Monday and will
hold through Tuesday bringing moderating temps and abundant sunshine.
Highs on Monday will range through the 30s toi near 40 and generally
range through the 40s on Tuesday.

Mid level shortwave will approach from the west Tuesday night
bringing increasing clouds and the chance for a little light mixed
precip after midnight. Associated surface low will gradually fill over
southern Quebec on Wednesday and will drive a weak cold front through
the region Wednesday evening. Will likely include some chance pops for
showers during the day but expect these to be light and spotty.


Short Term...Areas of LIFR and IFR conditions this morning over
southern areas in snow. VFR conditions further to the north. Conditions
improving during the late morning and midday hours. VFR
conditions expected tonight and Friday.

Long Term...
VFR with areas of MVFR ceilings Friday night. MVFR/IFR
ceilings/vsby developing Saturday into Saturday night. Becoming
VFR on Sunday. VFR Monday and Tuesday.


Short Term...Winds will continue to gust into gale force today.
The gradient relaxes tonight with SCA conditions and large
swells continuing.

Long Term...
SCA`s likely Friday night through Sunday.


NWS, USGS and GMRI wave runup output continues to indicate some
minor impact with high tide this afternoon. Expect some minor
splash-over and/or beach erosion in York and Rockingham
counties for this afternoon`s tide. We may be issuing a
statement to cover this very minor event. Wave periods will
increase today, allowing for wave action to ride up the beach
and to the dune systems.

A storm may form well off the coast out in the Atlantic early
next week, before retrograding well off the southern New England
and Mid Atlantic coastlines. This may allow for building, long
period swells to reach the Maine and New Hampshire coastline
during the early to mid week period next week, potentially
leading to some beach erosion splash-over.


MARINE...Gale Warning until 5 PM EDT this afternoon for ANZ150>154.


NEAR TERM...Curtis
TIDES/COASTAL FLOODING... is the U.S. government's official web portal to all federal, state and local government web resources and services.