Area Forecast Discussion
Issued by NWS Portland, ME-- Remove Highlighting --
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FXUS61 KGYX 221543
Area Forecast Discussion
National Weather Service Gray ME
1143 AM EDT Wed Mar 22 2017
An Arctic cold front crossing the area early this morning will
bring much colder temperatures and strong northwest winds today
and tonight. Very cold temperatures will continue through
Thursday. A warm front will move in from the west on Friday with
some light snow and rain ahead of it. Warmer temperatures will
not last long, though, as another cold front drops down from the
north on Saturday with more cold air expected for Sunday and
Monday. Low pressure tracking south of New England on Monday
could bring some light snow or a wintry mix of precipitation
Monday into Monday night. Another low pressure system will track
through New England on Wednesday with another chance of wintry
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --1130 AM UPDATE...
Last of the snow showers associated with this mornings fropa
currently diminishing in mid coast Maine and expect this
activity to push east of the forecast area early this afternoon
with clearing by mid afternoon. Clouds and snow showers will
hang tough in the moutains through this afternoon. Have updated
temp/td/rh/sky/pop and wx grids based on current trends and
surface obs. No other changes planned attm.
Snow squalls along the leading edge of the cold
front have managed to sneak out of the mountains. Have updated
the forecast to include a chance of snow primarily north of
Portland as this moves through. Winds behind the front have been
gusting to around 30 MPH and have been tracking the squall with
a Special Weather Statement.
An Arctic cold front is moving into the area this morning,
with some light snow spreading in behind it in the mountains.
Expect strong cold advection through the day today with 850 MB
temperatures dropping about 12C from 12Z to 00Z today. This
strong cold advection will promote excellent mixing of the low
levels today, especially to the southeast (downwind) of the
mountains. Winds aloft are about 40 to 45 KT and although this
is a little lower than what we would typically like to see for a
solid Wind Advisory type of day, the strong cold advection and
downsloping winds should maximize the mixing potential to the
southeast of the mountains, allowing the strongest winds aloft
to mix down. As a result, we have issued a Wind Advisory for the
areas that have the potential to see 45 to 50 MPH wind gusts
today. Winds aloft strengthen a bit this evening, and it is
possible that the strongest wind gusts may well occur in the
late afternoon or early evening. Thus the Wind Advisory will be
in effect until midnight when the gusts should begin to diminish
just a bit. Temperatures today will be falling from their early
morning levels, generally through the 20s as the day goes on.
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.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
Winds will diminish somewhat as the night goes on, but we should
still see a fairly windy night. Although we will not see good
radiational cooling conditions, temperatures will still drop
from cold advection alone. By morning most of the area will be
in the single digits, with some below zero readings possible to
the northwest of the mountains where the best low level cold air
gets banked up against the terrain. Wind Chill values will be
below zero area wide and near 20 below in the Maine mountains.
We may have to consider a Wind Chill Advisory if current
Record low temperature for Portland on Thursday, March 23 is 11
degrees set in 1959. The current forecast calls for this record
to be broken. At Concord the record low is -10 set in 1875 and
is not under threat of being broken.
High pressure slowly moves toward the area on Thursday with
lighter winds expected and slightly warmer temperatures. Most
areas will only see the temperature top out in the low 30s (20s
north of the mountains).
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
As the high pressure shifts offshore Thursday night...low temps
will still be below normal for this time of year in the single
digits to upper teens. The series of frontal systems on Friday
and into Saturday will allow for weak over-running precipitation
across the region.
Due to the cold morning lows temps on Friday...all precipitation
will start as snow and southern and coastal areas will
transition to rain in the afternoon. Models are still showing
difference in areal extent of the warming with ECMWF remaining
colder. As noted in previous discussions...the QPF amounts are
low and this should have minimal impacts. But...we should be
mindful of the chance of precipitation during commuting times on
Looking for lingering rain or snow showers to gradually end around
midnight as the cold frontal boundary moves through the region.
Saturday will have near normal to above normal temperatures and
isolated rain and snow showers. Temperatures will drop back
below normal on Sunday into Monday.
Models are in better agreement for the system affecting the
area Sunday night into Monday that will have the potential for
wintry mix to include a chance of freezing rain from the foot
hills to the coastal plain. There is a tight temperature
gradient just offshore and the location of this will be part of
the deciding factor on precipitation type.
All models continue to show a series of systems going through the
area early next week with potential for a mixed bag of
precipitation. Confidence is low for this time frame on
precipitation type and will mainly trend toward SB with minimal
Climate outlooks in Week 2 tend to show chance of warmer than
normal temperatures and above normal precipitation. After
looking at climate teleconnection...we will see a swing back
and fourth in temperatures above and below normal temperatures
as most remain in the positive phase but trend towards negative
for a bit. At this point...there is a series of weather system
with small amounts of QPF through day 7 which is below the 0.75
to 1 inch a week normal values this time a year. So we will need
an increase in weather systems to have above normal
precipitation and this should not be ruled out.
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
Short Term...Expect VFR conditions through the period outside of
some MVFR ceilings and light snow at Whitefield mainly this
morning. Northwest winds will gust to 30 to 40 KT today, mainly
to the southeast of the mountains. These wind gusts will
diminish a bit late tonight, but still expect 15 to 25 KT
Long Term...Expect a mixture of VFR and MVFR/IFR ceilings and
visibility through Sunday because of the serious of frontal
systems and lingering moisture from the showers.
Short Term...Strong cold advection behind an Arctic cold front
is expected to bring gale force northwest winds to the waters
today with winds eventually falling below gale force later
tonight. As the cold air arrives, the winds will promote
freezing spray, and a Freezing Spray Advisory continues into
Long Term...Expect a transition to small craft as the winds
diminish on Thursday morning through Friday.
-- Changed Discussion --ME...Wind Advisory until midnight EDT tonight for MEZ012>014-
NH...Wind Advisory until midnight EDT tonight for NHZ004-006-
MARINE...Freezing Spray Advisory from 7 PM this evening to 10 AM EDT
Thursday for ANZ150>154.
Gale Warning until midnight EDT tonight for ANZ153.
Gale Warning until 8 AM EDT Thursday for ANZ150>152-154.
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